Deuterium Exchange Measurement
Deuterium
Botany
Hydrogen
Deuterium Oxide
Plant Transpiration
Mass Spectrometry
Pulmonary Gas Exchange
Carbon Dioxide
Magnetic Resonance Spectroscopy
Photosynthesis
Plant Leaves
Group IA Phospholipases A2
Spectrometry, Mass, Electrospray Ionization
Models, Molecular
Amides
Protein Conformation
Spectroscopy, Fourier Transform Infrared
Protein Structure, Secondary
Pepsin A
Amino Acid Sequence
Molecular Sequence Data
Gases
Protein Structure, Tertiary
Peptides
Solvents
Protein Binding
Protons
Fourier Analysis
Nuclear Magnetic Resonance, Biomolecular
Water
Thermodynamics
Cyclotrons
Hydrogen-Ion Concentration
Hydrogen Bonding
Peptide Fragments
Spectrophotometry, Infrared
Binding Sites
Ligands
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Circular Dichroism
Protein Structure, Quaternary
Models, Chemical
Chromatography, Reverse-Phase
Myoglobin
Peptide Mapping
Molecular Structure
Protein Stability
Proteins
Deuterium solid-state NMR investigations of exchange labeled oriented purple membranes at different hydration levels. (1/418)
Oriented purple membranes were equilibrated under controlled (2)H(2)O relative humidity ranging from 15% to 93% and introduced into the magnetic field of an NMR spectrometer with the membrane normal parallel to the magnetic field direction. Deuterium solid-state NMR spectra of these samples resolved four deuteron populations. Deuterons that have exchanged with amide protons of the protein exhibited a broad spectral line shape (<150 kHz). Furthermore, a broadened signal of deuterons tightly associated with protein and lipid is detected at low hydration, as well as two additional water populations that were present when the samples were equilibrated at >/=75% relative humidity. These latter ones are characterized by narrow quadrupolar splittings (<2.5 kHz) and orientation-dependent chemical shifts. Their deuterium relaxation times, measured as a function of temperature, indicate correlation times in the fast regime (10(-10) s) and activation energies of 13 kJ/mol (at 86% relative humidity). Differences in T(1) and T(2) relaxation together with small residual quadrupole splittings show that the mobility of the deuterons is anisotropic. The occurrence of these mobile water populations at high levels of purple membrane hydration (>/=75% relative humidity) correlate with proton pumping activity of bacteriorhodopsin, the fast kinetics of M-decay in the bacteriorhodopsin photocycle, and structural alterations of the protein during the M-state, which have been described previously. (+info)Structurally homologous all beta-barrel proteins adopt different mechanisms of folding. (2/418)
Acidic fibroblast growth factors from human (hFGF-1) and newt (nFGF-1) (Notopthalamus viridescens) are 16-kDa, all beta-sheet proteins with nearly identical three-dimensional structures. Guanidine hydrochloride (GdnHCl)-induced unfolding of hFGF-1 and nFGF-1 monitored by fluorescence and far-UV circular dichroism (CD) shows that the FGF-1 isoforms differ significantly in their thermodynamic stabilities. GdnHCl-induced unfolding of nFGF-1 follows a two-state (Native state to Denatured state(s)) mechanism without detectable intermediate(s). By contrast, unfolding of hFGF-1 monitored by fluorescence, far-UV circular dichroism, size-exclusion chromatography, and NMR spectroscopy shows that the unfolding process is noncooperative and proceeds with the accumulation of stable intermediate(s) at 0.96 M GdnHCl. The intermediate (in hFGF-1) populated maximally at 0.96 M GdnHCl has molten globule-like properties and shows strong binding affinity to the hydrophobic dye, 1-Anilino-8-naphthalene sulfonate (ANS). Refolding kinetics of hFGF-1 and nFGF-1 monitored by stopped-flow fluorescence reveal that hFGF-1 and nFGF-1 adopts different folding mechanisms. The observed differences in the folding/unfolding mechanisms of nFGF-1 and hFGF-1 are proposed to be either due to differential stabilizing effects of the charged denaturant (Gdn(+) Cl(-)) on the intermediate state(s) and/or due to differences in the structural interactions stabilizing the native conformation(s) of the FGF-1 isoforms. (+info)Folding subdomains of thioredoxin characterized by native-state hydrogen exchange. (3/418)
Native-state hydrogen exchange (HX) studies, used in conjunction with NMR spectroscopy, have been carried out on Escherichia coli thioredoxin (Trx) for characterizing two folding subdomains of the protein. The backbone amide protons of only the slowest-exchanging 24 amino acid residues, of a total of 108 amino acid residues, could be followed at pH 7. The free energy of the opening event that results in an amide hydrogen exchanging with solvent (DeltaG(op)) was determined at each of the 24 amide hydrogen sites. The values of DeltaG(op) for the amide hydrogens belonging to residues in the helices alpha(1), alpha(2), and alpha(4) are consistent with them exchanging with the solvent only when the fully unfolded state is sampled transiently under native conditions. The denaturant-dependences of the values of DeltaG(op) provide very little evidence that the protein samples partially unfolded forms, lower in energy than the unfolded state. The amide hydrogens belonging to the residues in the beta strands, which form the core of the protein, appear to have higher values of DeltaG(op) than amide hydrogens belonging to residues in the helices, suggesting that they might be more stable to exchange. This apparently higher stability to HX of the beta strands might be either because they exchange out their amide hydrogens in a high energy intermediate preceding the globally unfolded state, or, more likely, because they form residual structure in the globally unfolded state. In either case, the central beta strands-beta(3,) beta(2), and beta(4)-would appear to form a cooperatively folding subunit of the protein. The native-state HX methodology has made it possible to characterize the free energy landscape that Trx can sample under equilibrium native conditions. (+info)Rapid analysis of protein structure and dynamics by hydrogen/deuterium exchange mass spectrometry. (4/418)
An automated approach for the rapid analysis of protein structure has been developed and used to study acid-induced conformational changes in human growth hormone. The labeling approach involves hydrogen/deuterium exchange (H/D-Ex) of protein backbone amide hydrogens with rapid and sensitive detection by mass spectrometry (MS). Briefly, the protein is incubated for defined intervals in a deuterated environment. After rapid quenching of the exchange reaction, the partially deuterated protein is enzymatically digested and the resulting peptide fragments are analyzed by liquid chromatography mass spectrometry (LC-MS). The deuterium buildup curve measured for each fragment yields an average amide exchange rate that reflects the environment of the peptide in the intact protein. Additional analyses allow mapping of the free energy of folding on localized segments along the protein sequence affording unique dynamic and structural information. While amide H/D-Ex coupled with MS is recognized as a powerful technique for studying protein structure and protein-ligand interactions, it has remained a labor-intensive task. The improvements in the amide H/D-Ex methodology described here include solid phase proteolysis, automated liquid handling and sample preparation, and integrated data reduction software that together improve sequence coverage and resolution, while achieving a sample throughput nearly 10-fold higher than the commonly used manual methods. (+info)Mapping temperature-induced conformational changes in the Escherichia coli heat shock transcription factor sigma 32 by amide hydrogen exchange. (5/418)
Stress conditions such as heat shock alter the transcriptional profile in all organisms. In Escherichia coli the heat shock transcription factor, sigma 32, out-competes upon temperature up-shift the housekeeping sigma-factor, sigma 70, for binding to core RNA polymerase and initiates heat shock gene transcription. To investigate possible heat-induced conformational changes in sigma 32 we performed amide hydrogen (H/D) exchange experiments under optimal growth and heat shock conditions combined with mass spectrometry. We found a rapid exchange of around 220 of the 294 amide hydrogens at 37 degrees C, indicating that sigma 32 adopts a highly flexible structure. At 42 degrees C we observed a slow correlated exchange of 30 additional amide hydrogens and localized it to a helix-loop-helix motif within domain sigma 2 that is responsible for the recognition of the -10 region in heat shock promoters. The correlated exchange is shown to constitute a reversible unfolding with a half-life of about 30 min due to a temperature-dependent decrease in stabilization energy. We propose that this gradual decrease in stabilization energy of domain sigma 2 with increasing temperatures facilitates the unfolding of sigma 32 by the AAA+ protease FtsH thereby decreasing its half-life. Taken together our data show that the sigma 2 domain of sigma 32 can act as a thermosensor, which might be important for the heat shock regulation. (+info)Protein stabilization by compatible solutes. Effect of diglycerol phosphate on the dynamics of Desulfovibrio gigas rubredoxin studied by NMR. (6/418)
Heteronuclear NMR relaxation measurements and hydrogen exchange data have been used to characterize protein dynamics in the presence or absence of stabilizing solutes from hyperthermophiles. Rubredoxin from Desulfovibrio gigas was selected as a model protein and the effect of diglycerol phosphate on its dynamic behaviour was studied. The presence of 100 mM diglycerol phosphate induces a fourfold increase in the half-life for thermal denaturation of D. gigas rubredoxin. A model-free analysis of the protein backbone relaxation parameters shows an average increase of generalized order parameters of 0.015 reflecting a small overall reduction in mobility of fast-scale motions. Hydrogen exchange data acquired over a temperature span of 20 degrees C yielded thermodynamic parameters for the structural opening reactions that allow for the exchange. This shows that the closed form of the protein is stabilized by an additional 1.6 kJ x mol(-1) in the presence of the solute. The results seem to indicate that the stabilizing effect is due mainly to a reduction in mobility of the slower, larger-scale motions within the protein structure with an associated increase in the enthalpy of interactions. (+info)Solvent and primary deuterium isotope effects show that lactate CH and OH bond cleavages are concerted in Y254F flavocytochrome b2, consistent with a hydride transfer mechanism. (7/418)
Yeast flavocytochrome b(2) catalyzes the oxidation of lactate to pyruvate; because of the wealth of structural and mechanistic information available, this enzyme has served as the model for the family of flavoproteins catalyzing oxidation of alpha-hydroxy acids. Primary deuterium and solvent isotope effects have now been used to analyze the effects of mutating the active site residue Tyr254 to phenylalanine. Both the V(max) and the V/K(lactate) values decrease about 40-fold in the mutant enzyme. The primary deuterium isotope effects on the V(max) and the V/K(lactate) values increase to 5.0, equivalent to the intrinsic isotope effect for the wild-type enzyme. In addition, both the V(max) and the V/K(lactate) values exhibit solvent isotope effects of 1.5. Measurement of the solvent isotope effect with deuterated lactate establishes that the primary and solvent isotope effects arise from the same chemical step, consistent with concerted cleavage of the lactate OH and CH bonds. The pH dependence of the mutant enzyme is not significantly different from that of the wild-type enzyme; this is most consistent with a requirement that the side chain of Tyr254 be uncharged for catalysis. The results support a hydride transfer mechanism for the mutant protein and, by extension, wild-type flavocytochrome b(2) and the other flavoproteins catalyzing oxidation of alpha-hydroxy acids. (+info)Uncoupled forms of tyrosine hydroxylase unmask kinetic isotope effects on chemical steps. (8/418)
Tyrosine hydroxylase (TyrH) catalyzes the hydroxylation of tyrosine to dihydroxyphenylalanine. In the proposed mechanism, a ferryl-oxo species attacks the aromatic ring of tyrosine, forming a cationic intermediate. However, no significant isotope effect is found for wild-type TyrH when 3,5-2H2-tyrosine is used as a substrate. The isotope effect has now been determined with 3,5-2H2-tyrosine using mutant forms of TyrH in which the oxidation of the pterin is uncoupled from hydroxylation of the amino acid. Three mutant enzymes exhibit significant inverse deuterium isotope effects and inverse solvent isotope effects. A proton inventory for the E326A enzyme is consistent with a normal solvent isotope effect of 2.4 on an unproductive step. The results support the proposed mechanism and demonstrate the utility of using mutant proteins with branched pathways to reveal isotope effects which are masked in the wild-type enzyme. (+info)Deuterium exchange measurement is a technique used in physical chemistry and biochemistry to study the structure, dynamics, and interactions of proteins, peptides, and other biological macromolecules. This method involves the exchange of deuterium (a heavy isotope of hydrogen) for hydrogen atoms in the molecule of interest.
The process typically begins with the preparation of a sample containing the macromolecule, which is then exposed to an environment with a high concentration of deuterated solvent, such as heavy water (D2O). Over time, some or all of the exchangeable hydrogen atoms in the molecule will be replaced by deuterium atoms through a series of chemical reactions.
The rate and extent of this deuterium exchange can provide valuable information about various aspects of the macromolecule's structure and behavior, including:
1. Solvent accessibility: Regions of the molecule that are exposed to solvent will typically undergo faster deuterium exchange than those that are buried within the protein's core or shielded by other structures. This allows researchers to identify which parts of the molecule are accessible to the solvent and infer information about its overall shape and conformation.
2. Dynamics: The rate of deuterium exchange can also be used to study the flexibility and dynamics of different regions of the macromolecule. Flexible or disordered regions will typically exhibit faster exchange rates than more rigid or structured ones, providing insights into the molecule's internal motions and conformational changes.
3. Interactions: Deuterium exchange measurements can also be used to study how the macromolecule interacts with other molecules, such as ligands, drugs, or other proteins. By comparing the deuterium exchange patterns in the presence and absence of these interaction partners, researchers can identify which regions of the molecule are involved in binding and learn more about the nature of these interactions.
There are several experimental methods for measuring deuterium exchange, including nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), and infrared spectroscopy (IR). Each method has its advantages and limitations, but all provide valuable information that can help researchers better understand the structure, dynamics, and function of biological macromolecules.
Deuterium is a stable and non-radioactive isotope of hydrogen. The atomic nucleus of deuterium, called a deuteron, contains one proton and one neutron, giving it an atomic weight of approximately 2.014 atomic mass units (amu). It is also known as heavy hydrogen or heavy water because its hydrogen atoms contain one neutron in addition to the usual one proton found in common hydrogen atoms.
Deuterium occurs naturally in trace amounts in water and other organic compounds, typically making up about 0.015% to 0.018% of all hydrogen atoms. It can be separated from regular hydrogen through various methods such as electrolysis or distillation, and it has many applications in scientific research, particularly in the fields of chemistry and physics.
In medical contexts, deuterium is sometimes used as a tracer to study metabolic processes in the body. By replacing hydrogen atoms in specific molecules with deuterium atoms, researchers can track the movement and transformation of those molecules within living organisms. This technique has been used to investigate various physiological processes, including drug metabolism, energy production, and lipid synthesis.
Botany is the scientific study of plants, encompassing various disciplines such as plant structure, function, evolution, diversity, distribution, ecology, and application. It involves examining different aspects like plant anatomy, physiology, genetics, molecular biology, systematics, and ethnobotany. The field of botany has contributed significantly to our understanding of the natural world, agriculture, medicine, and environmental conservation.
I'm sorry for any confusion, but "Hydrogen" is not a medical term. It is a chemical element with the symbol H and atomic number 1. It is the lightest and most abundant chemical element in the universe, making up about 75% of its elemental mass.
In a medical context, hydrogen can be discussed in terms of molecular hydrogen (H2) which has been studied for potential therapeutic benefits. Some research explores its use as an antioxidant and anti-inflammatory agent, but more studies are needed to confirm these effects and understand the mechanisms behind them.
Deuterium oxide, also known as heavy water, is a compound consisting of two atoms of deuterium (a heavy isotope of hydrogen) and one atom of oxygen. Its chemical formula is D2O. Deuterium oxide has physical and chemical properties similar to those of regular water (H2O), but its density and boiling point are slightly higher due to the increased atomic weight. It is used in various scientific research applications, including as a tracer in biochemical and medical studies.
Plant transpiration is the process by which water vapor escapes from leaves and other aerial parts of plants to the atmosphere. It is a type of evapotranspiration, which refers to both evaporation from land surfaces and transpiration from plants. Water molecules are absorbed by plant roots from the soil, move up through the xylem tissue to the leaves, and then evaporate from the leaf surface through stomatal pores. This process helps in the transportation of nutrients from the soil to various parts of the plant, regulates the temperature of the plant, and maintains the turgor pressure within the cells. Plant transpiration is influenced by environmental factors such as light intensity, temperature, humidity, and wind speed.
Mass spectrometry (MS) is an analytical technique used to identify and quantify the chemical components of a mixture or compound. It works by ionizing the sample, generating charged molecules or fragments, and then measuring their mass-to-charge ratio in a vacuum. The resulting mass spectrum provides information about the molecular weight and structure of the analytes, allowing for identification and characterization.
In simpler terms, mass spectrometry is a method used to determine what chemicals are present in a sample and in what quantities, by converting the chemicals into ions, measuring their masses, and generating a spectrum that shows the relative abundances of each ion type.
Pulmonary gas exchange is the process by which oxygen (O2) from inhaled air is transferred to the blood, and carbon dioxide (CO2), a waste product of metabolism, is removed from the blood and exhaled. This process occurs in the lungs, primarily in the alveoli, where the thin walls of the alveoli and capillaries allow for the rapid diffusion of gases between them. The partial pressure gradient between the alveolar air and the blood in the pulmonary capillaries drives this diffusion process. Oxygen-rich blood is then transported to the body's tissues, while CO2-rich blood returns to the lungs to be exhaled.
Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in the Earth's atmosphere. It is a normal byproduct of cellular respiration in humans, animals, and plants, and is also produced through the combustion of fossil fuels such as coal, oil, and natural gas.
In medical terms, carbon dioxide is often used as a respiratory stimulant and to maintain the pH balance of blood. It is also used during certain medical procedures, such as laparoscopic surgery, to insufflate (inflate) the abdominal cavity and create a working space for the surgeon.
Elevated levels of carbon dioxide in the body can lead to respiratory acidosis, a condition characterized by an increased concentration of carbon dioxide in the blood and a decrease in pH. This can occur in conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other lung diseases that impair breathing and gas exchange. Symptoms of respiratory acidosis may include shortness of breath, confusion, headache, and in severe cases, coma or death.
Magnetic Resonance Spectroscopy (MRS) is a non-invasive diagnostic technique that provides information about the biochemical composition of tissues, including their metabolic state. It is often used in conjunction with Magnetic Resonance Imaging (MRI) to analyze various metabolites within body tissues, such as the brain, heart, liver, and muscles.
During MRS, a strong magnetic field, radio waves, and a computer are used to produce detailed images and data about the concentration of specific metabolites in the targeted tissue or organ. This technique can help detect abnormalities related to energy metabolism, neurotransmitter levels, pH balance, and other biochemical processes, which can be useful for diagnosing and monitoring various medical conditions, including cancer, neurological disorders, and metabolic diseases.
There are different types of MRS, such as Proton (^1^H) MRS, Phosphorus-31 (^31^P) MRS, and Carbon-13 (^13^C) MRS, each focusing on specific elements or metabolites within the body. The choice of MRS technique depends on the clinical question being addressed and the type of information needed for diagnosis or monitoring purposes.
Photosynthesis is not strictly a medical term, but it is a fundamental biological process with significant implications for medicine, particularly in understanding energy production in cells and the role of oxygen in sustaining life. Here's a general biological definition:
Photosynthesis is a process by which plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy in the form of organic compounds, such as glucose (or sugar), using water and carbon dioxide. This process primarily takes place in the chloroplasts of plant cells, specifically in structures called thylakoids. The overall reaction can be summarized as:
6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
In this equation, carbon dioxide (CO2) and water (H2O) are the reactants, while glucose (C6H12O6) and oxygen (O2) are the products. Photosynthesis has two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions occur in the thylakoid membrane and involve the conversion of light energy into ATP and NADPH, which are used to power the Calvin cycle. The Calvin cycle takes place in the stroma of chloroplasts and involves the synthesis of glucose from CO2 and water using the ATP and NADPH generated during the light-dependent reactions.
Understanding photosynthesis is crucial for understanding various biological processes, including cellular respiration, plant metabolism, and the global carbon cycle. Additionally, research into artificial photosynthesis has potential applications in renewable energy production and environmental remediation.
I believe there may be a slight misunderstanding in your question. "Plant leaves" are not a medical term, but rather a general biological term referring to a specific organ found in plants.
Leaves are organs that are typically flat and broad, and they are the primary site of photosynthesis in most plants. They are usually green due to the presence of chlorophyll, which is essential for capturing sunlight and converting it into chemical energy through photosynthesis.
While leaves do not have a direct medical definition, understanding their structure and function can be important in various medical fields, such as pharmacognosy (the study of medicinal plants) or environmental health. For example, certain plant leaves may contain bioactive compounds that have therapeutic potential, while others may produce allergens or toxins that can impact human health.
Group IA Phospholipases A2 (PLA2s) are a subclass of phospholipases A2 that are characterized by their calcium-dependent enzymatic activity. They are a type of hydrolase enzyme that cleaves the sn-2 ester bond of glycerophospholipids, releasing free fatty acids and lysophospholipids.
In particular, Group IA PLA2s prefer to act on phosphatidylcholine (PC) substrates, and they play important roles in various biological processes, including inflammation, host defense, and lipid metabolism. These enzymes are secreted by various cells, such as pancreatic acinar cells, macrophages, and neutrophils, and can be activated by a variety of stimuli, including cytokines, bacterial products, and oxidative stress.
Group IA PLA2s are also known to contribute to the development and progression of several diseases, such as atherosclerosis, arthritis, and neurodegenerative disorders. Therefore, they have been considered as potential therapeutic targets for these conditions.
Mass spectrometry with electrospray ionization (ESI-MS) is an analytical technique used to identify and quantify chemical species in a sample based on the mass-to-charge ratio of charged particles. In ESI-MS, analytes are ionized through the use of an electrospray, where a liquid sample is introduced through a metal capillary needle at high voltage, creating an aerosol of charged droplets. As the solvent evaporates, the analyte molecules become charged and can be directed into a mass spectrometer for analysis.
ESI-MS is particularly useful for the analysis of large biomolecules such as proteins, peptides, and nucleic acids, due to its ability to gently ionize these species without fragmentation. The technique provides information about the molecular weight and charge state of the analytes, which can be used to infer their identity and structure. Additionally, ESI-MS can be interfaced with separation techniques such as liquid chromatography (LC) for further purification and characterization of complex samples.
Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.
Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.
Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.
An amide is a functional group or a compound that contains a carbonyl group (a double-bonded carbon atom) and a nitrogen atom. The nitrogen atom is connected to the carbonyl carbon atom by a single bond, and it also has a lone pair of electrons. Amides are commonly found in proteins and peptides, where they form amide bonds (also known as peptide bonds) between individual amino acids.
The general structure of an amide is R-CO-NHR', where R and R' can be alkyl or aryl groups. Amides can be classified into several types based on the nature of R and R' substituents:
* Primary amides: R-CO-NH2
* Secondary amides: R-CO-NHR'
* Tertiary amides: R-CO-NR''R'''
Amides have several important chemical properties. They are generally stable and resistant to hydrolysis under neutral or basic conditions, but they can be hydrolyzed under acidic conditions or with strong bases. Amides also exhibit a characteristic infrared absorption band around 1650 cm-1 due to the carbonyl stretching vibration.
In addition to their prevalence in proteins and peptides, amides are also found in many natural and synthetic compounds, including pharmaceuticals, dyes, and polymers. They have a wide range of applications in chemistry, biology, and materials science.
Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.
Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.
Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.
Fourier Transform Infrared (FTIR) spectroscopy is a type of infrared spectroscopy that uses the Fourier transform mathematical technique to convert the raw data obtained from an interferometer into a more interpretable spectrum. This technique allows for the simultaneous collection of a wide range of wavelengths, resulting in increased sensitivity and speed compared to traditional dispersive infrared spectroscopy.
FTIR spectroscopy measures the absorption or transmission of infrared radiation by a sample as a function of frequency, providing information about the vibrational modes of the molecules present in the sample. This can be used for identification and quantification of chemical compounds, analysis of molecular structure, and investigation of chemical interactions and reactions.
In summary, FTIR spectroscopy is a powerful analytical technique that uses infrared radiation to study the vibrational properties of molecules, with increased sensitivity and speed due to the use of Fourier transform mathematical techniques and an interferometer.
Secondary protein structure refers to the local spatial arrangement of amino acid chains in a protein, typically described as regular repeating patterns held together by hydrogen bonds. The two most common types of secondary structures are the alpha-helix (α-helix) and the beta-pleated sheet (β-sheet). In an α-helix, the polypeptide chain twists around itself in a helical shape, with each backbone atom forming a hydrogen bond with the fourth amino acid residue along the chain. This forms a rigid rod-like structure that is resistant to bending or twisting forces. In β-sheets, adjacent segments of the polypeptide chain run parallel or antiparallel to each other and are connected by hydrogen bonds, forming a pleated sheet-like arrangement. These secondary structures provide the foundation for the formation of tertiary and quaternary protein structures, which determine the overall three-dimensional shape and function of the protein.
Pepsin A is defined as a digestive enzyme that is primarily secreted by the chief cells in the stomach's fundic glands. It plays a crucial role in protein catabolism, helping to break down food proteins into smaller peptides during the digestive process. Pepsin A has an optimal pH range of 1.5-2.5 for its enzymatic activity and is activated from its inactive precursor, pepsinogen, upon exposure to acidic conditions in the stomach.
In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."
1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.
2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.
3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.
4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).
Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.
An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.
In medical terms, gases refer to the state of matter that has no fixed shape or volume and expands to fill any container it is placed in. Gases in the body can be normal, such as the oxygen, carbon dioxide, and nitrogen that are present in the lungs and blood, or abnormal, such as gas that accumulates in the digestive tract due to conditions like bloating or swallowing air.
Gases can also be used medically for therapeutic purposes, such as in the administration of anesthesia or in the treatment of certain respiratory conditions with oxygen therapy. Additionally, measuring the amount of gas in the body, such as through imaging studies like X-rays or CT scans, can help diagnose various medical conditions.
Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.
Protein unfolding, also known as protein denaturation, refers to the loss of a protein's native structure, leading to a random or disordered conformation. Proteins are complex molecules that fold into specific three-dimensional shapes, allowing them to perform their biological functions. Various factors, such as heat, changes in pH, chemical denaturants, or mechanical forces, can disrupt the delicate balance of interactions that maintain this folded structure, causing the protein to unfold. Unfolded proteins may lose their functionality and can aggregate, forming insoluble aggregates, which can be harmful to cells and contribute to various diseases, including neurodegenerative disorders.
Molecular conformation, also known as spatial arrangement or configuration, refers to the specific three-dimensional shape and orientation of atoms that make up a molecule. It describes the precise manner in which bonds between atoms are arranged around a molecular framework, taking into account factors such as bond lengths, bond angles, and torsional angles.
Conformational isomers, or conformers, are different spatial arrangements of the same molecule that can interconvert without breaking chemical bonds. These isomers may have varying energies, stability, and reactivity, which can significantly impact a molecule's biological activity and function. Understanding molecular conformation is crucial in fields such as drug design, where small changes in conformation can lead to substantial differences in how a drug interacts with its target.
Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.
Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.
Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.
Solvents, in a medical context, are substances that are capable of dissolving or dispersing other materials, often used in the preparation of medications and solutions. They are commonly organic chemicals that can liquefy various substances, making it possible to administer them in different forms, such as oral solutions, topical creams, or injectable drugs.
However, it is essential to recognize that solvents may pose health risks if mishandled or misused, particularly when they contain volatile organic compounds (VOCs). Prolonged exposure to these VOCs can lead to adverse health effects, including respiratory issues, neurological damage, and even cancer. Therefore, it is crucial to handle solvents with care and follow safety guidelines to minimize potential health hazards.
Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.
In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.
Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.
In the context of medicine, particularly in relation to cancer treatment, protons refer to positively charged subatomic particles found in the nucleus of an atom. Proton therapy, a type of radiation therapy, uses a beam of protons to target and destroy cancer cells with high precision, minimizing damage to surrounding healthy tissue. The concentrated dose of radiation is delivered directly to the tumor site, reducing side effects and improving quality of life during treatment.
I'm sorry for any confusion, but Fourier Analysis is not a medical term. It is a mathematical concept used in various scientific fields, including physics, engineering, and signal processing.
Fourier Analysis is a method to decompose functions into sinusoidal components (sines and cosines) of different frequencies. This allows for the representation of a function or a signal as a sum of these frequency components. It's particularly useful in analyzing periodic functions, understanding signals, and solving partial differential equations.
If you have any medical terms you would like me to define, please let me know!
Protein folding is the process by which a protein molecule naturally folds into its three-dimensional structure, following the synthesis of its amino acid chain. This complex process is determined by the sequence and properties of the amino acids, as well as various environmental factors such as temperature, pH, and the presence of molecular chaperones. The final folded conformation of a protein is crucial for its proper function, as it enables the formation of specific interactions between different parts of the molecule, which in turn define its biological activity. Protein misfolding can lead to various diseases, including neurodegenerative disorders such as Alzheimer's and Parkinson's disease.
Nuclear Magnetic Resonance (NMR) Biomolecular is a research technique that uses magnetic fields and radio waves to study the structure and dynamics of biological molecules, such as proteins and nucleic acids. This technique measures the magnetic properties of atomic nuclei within these molecules, specifically their spin, which can be influenced by the application of an external magnetic field.
When a sample is placed in a strong magnetic field, the nuclei absorb and emit electromagnetic radiation at specific frequencies, known as resonance frequencies, which are determined by the molecular structure and environment of the nuclei. By analyzing these resonance frequencies and their interactions, researchers can obtain detailed information about the three-dimensional structure, dynamics, and interactions of biomolecules.
NMR spectroscopy is a non-destructive technique that allows for the study of biological molecules in solution, which makes it an important tool for understanding the function and behavior of these molecules in their natural environment. Additionally, NMR can be used to study the effects of drugs, ligands, and other small molecules on biomolecular structure and dynamics, making it a valuable tool in drug discovery and development.
Medical definitions of water generally describe it as a colorless, odorless, tasteless liquid that is essential for all forms of life. It is a universal solvent, making it an excellent medium for transporting nutrients and waste products within the body. Water constitutes about 50-70% of an individual's body weight, depending on factors such as age, sex, and muscle mass.
In medical terms, water has several important functions in the human body:
1. Regulation of body temperature through perspiration and respiration.
2. Acting as a lubricant for joints and tissues.
3. Facilitating digestion by helping to break down food particles.
4. Transporting nutrients, oxygen, and waste products throughout the body.
5. Helping to maintain healthy skin and mucous membranes.
6. Assisting in the regulation of various bodily functions, such as blood pressure and heart rate.
Dehydration can occur when an individual does not consume enough water or loses too much fluid due to illness, exercise, or other factors. This can lead to a variety of symptoms, including dry mouth, fatigue, dizziness, and confusion. Severe dehydration can be life-threatening if left untreated.
I'm sorry for any confusion, but "thermodynamics" is not a term that has a specific medical definition. It is a branch of physics that deals with the relationships between heat and other forms of energy. However, the principles of thermodynamics can be applied to biological systems, including those in the human body, such as in the study of metabolism or muscle function. But in a medical context, "thermodynamics" would not be a term used independently as a diagnosis, treatment, or any medical condition.
A cyclotron is a type of particle accelerator that uses a magnetic field and electric field to increase the velocity of charged particles (such as protons or ions) up to high speeds. This device forms a spiral path, with the particles traveling in a circular motion within two flat, semi-circular electrodes called "dees" while being accelerated by an alternating voltage. As the particles reach the outer edge of the dees, they are deflected by a magnetic field and travel through a spiral path, gaining energy with each rotation until they reach the desired energy level.
Cyclotrons are commonly used in nuclear medicine to produce radioisotopes for medical imaging and cancer treatment. They can also be used for research purposes, such as studying the properties of subatomic particles or creating new isotopes for various applications.
Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.
In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.
Hydrogen bonding is not a medical term per se, but it is a fundamental concept in chemistry and biology that is relevant to the field of medicine. Here's a general definition:
Hydrogen bonding is a type of attractive force between molecules or within a molecule, which occurs when a hydrogen atom is bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and is then attracted to another electronegative atom. This attraction results in the formation of a partially covalent bond known as a "hydrogen bond."
In biological systems, hydrogen bonding plays a crucial role in the structure and function of many biomolecules, such as DNA, proteins, and carbohydrates. For example, the double helix structure of DNA is stabilized by hydrogen bonds between complementary base pairs (adenine-thymine and guanine-cytosine). Similarly, the three-dimensional structure of proteins is maintained by a network of hydrogen bonds that help to determine their function.
In medical contexts, hydrogen bonding can be relevant in understanding drug-receptor interactions, where hydrogen bonds between a drug molecule and its target protein can enhance the binding affinity and specificity of the interaction, leading to more effective therapeutic outcomes.
A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.
Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.
Spectrophotometry, Infrared is a scientific analytical technique used to measure the absorption or transmission of infrared light by a sample. It involves the use of an infrared spectrophotometer, which directs infrared radiation through a sample and measures the intensity of the radiation that is transmitted or absorbed by the sample at different wavelengths within the infrared region of the electromagnetic spectrum.
Infrared spectroscopy can be used to identify and quantify functional groups and chemical bonds present in a sample, as well as to study the molecular structure and composition of materials. The resulting infrared spectrum provides a unique "fingerprint" of the sample, which can be compared with reference spectra to aid in identification and characterization.
Infrared spectrophotometry is widely used in various fields such as chemistry, biology, pharmaceuticals, forensics, and materials science for qualitative and quantitative analysis of samples.
In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.
The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.
In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.
Body water refers to the total amount of water present in the human body. It is an essential component of life and makes up about 60-70% of an adult's body weight. Body water is distributed throughout various fluid compartments within the body, including intracellular fluid (water inside cells), extracellular fluid (water outside cells), and transcellular fluid (water found in specific bodily spaces such as the digestive tract, eyes, and joints). Maintaining proper hydration and balance of body water is crucial for various physiological processes, including temperature regulation, nutrient transportation, waste elimination, and overall health.
A ligand, in the context of biochemistry and medicine, is a molecule that binds to a specific site on a protein or a larger biomolecule, such as an enzyme or a receptor. This binding interaction can modify the function or activity of the target protein, either activating it or inhibiting it. Ligands can be small molecules, like hormones or neurotransmitters, or larger structures, like antibodies. The study of ligand-protein interactions is crucial for understanding cellular processes and developing drugs, as many therapeutic compounds function by binding to specific targets within the body.
Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a type of mass spectrometry that is used to analyze large biomolecules such as proteins and peptides. In this technique, the sample is mixed with a matrix compound, which absorbs laser energy and helps to vaporize and ionize the analyte molecules.
The matrix-analyte mixture is then placed on a target plate and hit with a laser beam, causing the matrix and analyte molecules to desorb from the plate and become ionized. The ions are then accelerated through an electric field and into a mass analyzer, which separates them based on their mass-to-charge ratio.
The separated ions are then detected and recorded as a mass spectrum, which can be used to identify and quantify the analyte molecules present in the sample. MALDI-MS is particularly useful for the analysis of complex biological samples, such as tissue extracts or biological fluids, because it allows for the detection and identification of individual components within those mixtures.
Circular dichroism (CD) is a technique used in physics and chemistry to study the structure of molecules, particularly large biological molecules such as proteins and nucleic acids. It measures the difference in absorption of left-handed and right-handed circularly polarized light by a sample. This difference in absorption can provide information about the three-dimensional structure of the molecule, including its chirality or "handedness."
In more technical terms, CD is a form of spectroscopy that measures the differential absorption of left and right circularly polarized light as a function of wavelength. The CD signal is measured in units of millidegrees (mdeg) and can be positive or negative, depending on the type of chromophore and its orientation within the molecule.
CD spectra can provide valuable information about the secondary and tertiary structure of proteins, as well as the conformation of nucleic acids. For example, alpha-helical proteins typically exhibit a strong positive band near 190 nm and two negative bands at around 208 nm and 222 nm, while beta-sheet proteins show a strong positive band near 195 nm and two negative bands at around 217 nm and 175 nm.
CD spectroscopy is a powerful tool for studying the structural changes that occur in biological molecules under different conditions, such as temperature, pH, or the presence of ligands or other molecules. It can also be used to monitor the folding and unfolding of proteins, as well as the binding of drugs or other small molecules to their targets.
Quaternary protein structure refers to the arrangement and interaction of multiple folded protein molecules in a multi-subunit complex. These subunits can be identical or different forms of the same protein or distinctly different proteins that associate to form a functional complex. The quaternary structure is held together by non-covalent interactions, such as hydrogen bonds, ionic bonds, and van der Waals forces. Understanding quaternary structure is crucial for comprehending the function, regulation, and assembly of many protein complexes involved in various cellular processes.
A chemical model is a simplified representation or description of a chemical system, based on the laws of chemistry and physics. It is used to explain and predict the behavior of chemicals and chemical reactions. Chemical models can take many forms, including mathematical equations, diagrams, and computer simulations. They are often used in research, education, and industry to understand complex chemical processes and develop new products and technologies.
For example, a chemical model might be used to describe the way that atoms and molecules interact in a particular reaction, or to predict the properties of a new material. Chemical models can also be used to study the behavior of chemicals at the molecular level, such as how they bind to each other or how they are affected by changes in temperature or pressure.
It is important to note that chemical models are simplifications of reality and may not always accurately represent every aspect of a chemical system. They should be used with caution and validated against experimental data whenever possible.
Reverse-phase chromatography is a type of liquid chromatography that is commonly used in analytical chemistry and biochemistry to separate, identify, and purify complex mixtures of chemicals or biological molecules. In this technique, the stationary phase is a nonpolar solid, such as octadecyl silica (ODS) or C18, which is coated with a polar solvent, while the mobile phase is a nonpolar solvent, such as methanol or acetonitrile.
The term "reverse-phase" refers to the fact that the polarity of the stationary and mobile phases is reversed compared to normal-phase chromatography. In normal-phase chromatography, the stationary phase is polar and the mobile phase is nonpolar, which results in the separation of analytes based on their polarity. However, in reverse-phase chromatography, the stationary phase is nonpolar and the mobile phase is polar, which means that the separation of analytes is based on their hydrophobicity or hydrophilicity.
In reverse-phase chromatography, hydrophobic molecules elute more slowly than hydrophilic molecules because they have a stronger affinity for the nonpolar stationary phase. The retention time of an analyte can be adjusted by changing the composition of the mobile phase or the pH of the solution. This technique is widely used in the analysis of drugs, metabolites, peptides, proteins, and other biological molecules.
Myoglobin is a protein found in the muscle tissue, particularly in red or skeletal muscles. It belongs to the globin family and has a similar structure to hemoglobin, another oxygen-binding protein found in red blood cells. Myoglobin's primary function is to store oxygen within the muscle cells, making it readily available for use during periods of increased oxygen demand, such as during physical exertion.
Myoglobin contains heme groups that bind to and release oxygen molecules. The protein has a higher affinity for oxygen than hemoglobin, allowing it to maintain its bound oxygen even in low-oxygen environments. When muscle cells are damaged or undergo necrosis (cell death), myoglobin is released into the bloodstream and can be detected in serum or urine samples. Elevated levels of myoglobin in the blood or urine may indicate muscle injury, trauma, or diseases affecting muscle integrity, such as rhabdomyolysis or muscular dystrophies.
Peptide mapping is a technique used in proteomics and analytical chemistry to analyze and identify the sequence and structure of peptides or proteins. This method involves breaking down a protein into smaller peptide fragments using enzymatic or chemical digestion, followed by separation and identification of these fragments through various analytical techniques such as liquid chromatography (LC) and mass spectrometry (MS).
The resulting peptide map serves as a "fingerprint" of the protein, providing information about its sequence, modifications, and structure. Peptide mapping can be used for a variety of applications, including protein identification, characterization of post-translational modifications, and monitoring of protein degradation or cleavage.
In summary, peptide mapping is a powerful tool in proteomics that enables the analysis and identification of proteins and their modifications at the peptide level.
Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.
Protein stability refers to the ability of a protein to maintain its native structure and function under various physiological conditions. It is determined by the balance between forces that promote a stable conformation, such as intramolecular interactions (hydrogen bonds, van der Waals forces, and hydrophobic effects), and those that destabilize it, such as thermal motion, chemical denaturation, and environmental factors like pH and salt concentration. A protein with high stability is more resistant to changes in its structure and function, even under harsh conditions, while a protein with low stability is more prone to unfolding or aggregation, which can lead to loss of function or disease states, such as protein misfolding diseases.
Proteins are complex, large molecules that play critical roles in the body's functions. They are made up of amino acids, which are organic compounds that are the building blocks of proteins. Proteins are required for the structure, function, and regulation of the body's tissues and organs. They are essential for the growth, repair, and maintenance of body tissues, and they play a crucial role in many biological processes, including metabolism, immune response, and cellular signaling. Proteins can be classified into different types based on their structure and function, such as enzymes, hormones, antibodies, and structural proteins. They are found in various foods, especially animal-derived products like meat, dairy, and eggs, as well as plant-based sources like beans, nuts, and grains.
Hydrogen-deuterium exchange
Hydrogen isotope biogeochemistry
Madison Symmetric Torus
Vienna Standard Mean Ocean Water
Orotidine 5'-phosphate decarboxylase
Michael L. Gross (chemist)
Plasma diagnostics
Deuterium
Nuclear force
Harmon Craig
Alpha helix
Charge exchange
Intrinsically disordered proteins
Deuterium-depleted water
Comet Hyakutake
Position-specific isotope analysis
Nuclear magnetic resonance spectroscopy of proteins
DD
Herbert H. Chen
D (disambiguation)
Lisa Jones (scientist)
Iodine
Proton
Sudbury Neutrino Observatory
Wilhelm Ostwald Institute
TAE Technologies
Neutron spin echo
CM chondrite
Electron affinity (data page)
Dye 3
Hydrogen-deuterium exchange - Wikipedia
Resources - Pelican
Publications | Max Planck Institute for Multidisciplinary Sciences
APS -52nd Annual Meeting of the APS Division of Plasma Physics - Event - Deuterium alpha line measurements and neutral density...
Flow Injection Analysis | Harvard Catalyst Profiles | Harvard Catalyst
Research Opportunities
Receptors, Transferrin | Profiles RNS
Glucose Clamp Technique | Profiles RNS
Oxygen and hydrogen isotope ratios in cherts and related rocks - CaltechTHESIS
Understanding nuclear mass defect - Physics Stack Exchange
Hydrogen interaction with polycyclic aromatic hydrocarbons - from interstellar catalysis to hydrogen storage | HPAH | Project |...
Prof. dr hab. Michał Dadlez - Instytut Biochemii i Biofizyki Polskiej Akademii Nauk
Pesquisa | Portal Regional da BVS
List of Articles
DeCS
HDExaminer in the Literature - Sierra Analytics
DeCS 2004 - Novos termos
DeCS 2004 - Nuevos términos
DeCS 2004 - Nuevos términos
DeCS 2004 - Nuevos términos
DeCS 2004 - New terms
DeCS 2004 - Novos termos
DeCS 2004 - Novos termos
DeCS 2004 - New terms
DeCS 2004 - Nuevos términos
DeCS 2004 - New terms
DeCS 2004 - Nuevos términos
Atoms9
- The use of acid, base or metal catalysts, coupled with conditions of increased temperature and pressure, can facilitate the exchange of non-exchangeable hydrogen atoms, so long as the substrate is robust to the conditions and reagents employed. (wikipedia.org)
- This often results in perdeuteration: hydrogen-deuterium exchange of all non-exchangeable hydrogen atoms in a molecule. (wikipedia.org)
- For the backbone amide hydrogen atoms of proteins, the minimum exchange rate occurs at approximately pH 2.6, on average. (wikipedia.org)
- By using the deuterium isotope of hydrogen it is possible to monitor the exchange between the initial H atoms on the PAH molecule and incoming D atoms from the atom beam. (europa.eu)
- Urey published numerous papers on the structure of atoms and molecules, the discovery of heavy hydrogen and its properties, isotope separation, paleotemperature measurement, and the genesis of planets. (thescandoreview.com)
- Our approach is based on the characterization of compounds by the number of labile hydrogen and oxygen atoms in the molecule, which can be measured using hydrogen/deuterium and 16O/18O-exchange approaches. (bgu.ac.il)
- Because of the facile enolization by zinc(II), the methylene hydrogen atoms (adjacent to the carbonyl) of ZnL were readily exchanged by deuterium under physiological conditions. (figshare.com)
- By selectively replacing hydrogen atoms with deuterium atoms, researchers can follow reaction steps, unraveling important details of a chemical transformation. (thalesnano.com)
- The dilution space is derived from the post-dose enrichment, and converted to total body water (TBW) after adjustment for the non-aqueous exchange of hydrogen atoms in the body (TBW=Dilution Space/1.04). (who.int)
Proton10
- Characterization of H/D exchange in type 1 pili by proton-detected solid-state NMR and molecular dynamics simulations. (mpg.de)
- Gas-phase ion molecule reaction kinetics such as hydrogen deuterium exchange (HDX) and proton affinity (PA) measurements? (baylor.edu)
- Measurements of the energy and angle of the protons arising in the interactions were sufficient to establish that photodisintegration without pion emission occurred and also to determine the energy of the photon which gave rise to the detected proton. (caltech.edu)
- The size of the proton is not yet fully understood, with a significant discrepancy between results obtained from Lamb shift measurements on electronic and muonic hydrogen. (manchester.ac.uk)
- An independent value for the proton radius may be obtained from measurements on deuterium, but for an accurate calculation a detailed understanding of the deuteronâ s structure is needed. (manchester.ac.uk)
- They used this technique to measure an important reaction where a neutron from a deuterium target is exchanged with a proton from a radioactive projectile, in this case oxygen-14. (techandsciencepost.com)
- 10. Z. Luz and S. Meiboom, Kinetics of proton exchange in aqueous solutions of acetate buffer. (weizmann.ac.il)
- 13. Z. Luz and S. Meiboom, Proton relaxation in dilute solution of cobalt(II) and nickel(II) ions in methanol and the rate of methanol exchange of the solvation sphere. (weizmann.ac.il)
- 16. Z. Luz and S. Meiboom, Rate and mechanism of proton exchange in aqueous solutions of phosphate buffer. (weizmann.ac.il)
- 17. Z. Luz and S. Meiboom, Rate and mechanism of proton exchange in aqueous solutions of phenol-sodium phenolate buffer. (weizmann.ac.il)
Isotope3
- The feasibility of making meaningful measurements of the deuterium content of water extracted from hydrous silica has been evaluated by a series of dehydration and isotope exchange experiments. (caltech.edu)
- At the National Superconducting Cyclotron Laboratory (now the Facility for Rare Isotope Beams or FRIB), researchers used the Active Target Time Projection Chamber coupled to the S800 magnetic spectrometer to measure a charge-exchange reaction between a radioactive oxygen-14 beam and a deuterium target. (techandsciencepost.com)
- The seals were offered daily amounts of capelin and kept under a seasonal photoperiod of 69°N. Large seasonal variations of deuterium and oxygen-18 in the pool water were measured, and the isotope abundance in the body water showed similar seasonal changes to the pool water. (biologists.com)
Spectroscopy7
- In modern times, H-D exchange has primarily been monitored by the methods: NMR spectroscopy, mass spectrometry and neutron crystallography. (wikipedia.org)
- Analysis via 13C NMR spectroscopy is also possible: the different spin values of hydrogen (1/2) and deuterium (1) gives rise to different splitting multiplicities. (wikipedia.org)
- Knowledge of the core neutral particle density is required to calculate fast ion confinement time and interpret charge exchange recombination spectroscopy data. (aps.org)
- In fact, mass spectroscopy of hydrogen and deuterium ions and diffraction-based measurements of the wavelength (and thence energy) of the $\rm npd\gamma$ photon are how we obtain the best estimate of the neutron's mass. (stackexchange.com)
- Ultraviolet photoemission spectroscopy measurements demonstrates that a bandgap of at least 450 meV is opened in graphene by the hydrogen nano-patterns. (europa.eu)
- Deuterium-labeled molecules are extensively used in Nuclear Magnetic Resonance spectroscopy, providing valuable information about molecular structures. (thalesnano.com)
- 14. Z. Luz, Nuclear magnetic resonance and optical spectroscopy of [Co(MeOH)5Cl]+ in methanol and the kinetics of methanol exchange of the solvation shell. (weizmann.ac.il)
Equilibrium5
- Since this exchange is an equilibrium reaction, the molar amount of deuterium should be high compared to the exchangeable protons of the substrate. (wikipedia.org)
- Non-equilibrium hydrogen exchange for determination of H-bond strength and water accessibility in solid proteins. (mpg.de)
- The fraction of the water or hydroxyl groups that is most resistant to exchange and most difficult to drive off is that water or hydroxyl group most likely to contain the hydrogen which was in equilibrium with the waters from which the silica formed. (caltech.edu)
- He researched their properties extensively, particularly the vapour pressure of hydrogen and deuterium and the equilibrium constants of exchange reactions. (thescandoreview.com)
- A saliva sample will be obtained prior to the dose and at 3 hours post-dose when the deuterium has reached equilibrium with the total body water, using a cotton swab. (who.int)
Ions2
- Predictions of the impact of charge-exchange (CX) reactions on beam ions in the MAST Upgrade spherical tokamak have been compared to measurements carried out with a fission chamber (neutron fluxes) and a Fast Ion Deuterium-Alpha (FIDA) diagnostic. (ukaea.uk)
- It was observed that when CX losses of beam ions are accounted for, predictions of neutron emission rates are more consistent with the measurements. (ukaea.uk)
Amide3
- By performing the exchange at neutral pH and then rapidly changing the pH, the exchange rates of the backbone amide hydrogens can be dramatically slowed, or quenched. (wikipedia.org)
- Application of amide hydrogen/deuterium exchange mass spectrometry for epitope mapping in human cystatin C . Amino acids 48, no. 12 (2016): 2809-2820. (massspec.com)
- All proteins have amide groups along their polypeptide backbone which routinely undergo a phenomenon of solvent exchange - where the hydrogen of the amide swaps with the hydrogen of the surrounding solvent, typically water. (ukri.org)
Protein14
- For instance, deuterium is added to a protein in H2O by diluting the H2O solution with D2O (e.g. tenfold). (wikipedia.org)
- Measurement of backbone hydrogen-deuterium exchange in the type III secretion system needle protein PrgI by solid-state NMR. (mpg.de)
- Mass spectrometric approaches to protein structure characterization are offered, including hydrogen-deuterium exchange, X-linking, native mass spectrometry, and ion mobility. (edu.pl)
- 74] V. Chevelkov, K. Giller, S. Becker, and A. Lange, Measurement of backbone hydrogen-deuterium exchange in the type III secretion system needle protein PrgI by solid-state NMR, Journal of Magnetic Resonance , 283 (2017), pp. 110-116. (leibniz-fmp.de)
- Hydrogen exchange (HX) mass spectrometry (MS) is dear for providing conformational details for protein/peptides that have become difficult to investigate with other strategies such as for example peripheral membrane protein and peptides that connect to membranes. (tech-strategy.org)
- Hydrogen Deuterium Exchange Mass Spectrometry (HDX-MS) is a structural biology technique which excels in the investigation of protein interactions. (ukri.org)
- Areas of protein which are rigid, densely packed and highly structured have a much slower solvent exchange rate than disordered, flexible and loosely packed parts of the protein. (ukri.org)
- Additionally, the creating of new bonds through the creation of new interaction interfaces, whether that be protein: protein interactions, or protein: drug, protein: membrane, or protein: nucleic acid, will all alter the solvent exchange rate. (ukri.org)
- The measurement solvent exchange is achieved through the exposure of a protein to a deuterated solvent. (ukri.org)
- Using mass spectrometry equipment, we can detect this increase in mass, and by incubating the protein with deuterium for multiple time points, we can measure the solvent exchange rate. (ukri.org)
- The solvent exchange rate can then be manipulated by e.g. adding a drug which interacts with the protein, and determine where on the protein the solvent exchange rate is altered, thus locate where on a protein a drug, binding partner, or lipid membrane is interacting. (ukri.org)
- In a second part, methods to study the surface accessibility of protein complexes by chemical modification in solution, either reversible (H/D exchange) or irreversible (specific modification of His and Lys by DEPC) were developed and implemented. (hal.science)
- Increase in deuterium incorporation in some regions of the oligomeric species (compared to the monomer) reflects partial unfolding of the protein, as indicated by the unfolding of an α helix. (hal.science)
- More- over, internal water exchange is believed to be governed by confor- mational ¯uctuations in the protein and can therefore provide information about the thermal accessibility of functionally important con- formational substates. (lu.se)
Nuclei2
- Hydrogen and deuterium nuclei are grossly different in their magnetic properties. (wikipedia.org)
- Consistent values of the masses of the light nuclei have been calculated from the best measurements of Q-values for several nuclear reactions, and from mass spectrographic measurements. (caltech.edu)
Mass11
- For detection by mass spectrometry, the pH is dropped to the minimum of the exchange curve, pH 2.6. (wikipedia.org)
- Flow injection tandem mass spectrometric measurement of ceramides of multiple chain lengths in biological samples. (harvard.edu)
- Soya, N., Roldan, A., & Lukacs, G. L. Differential Scanning Fluorimetry and Hydrogen Deuterium Exchange Mass Spectrometry to Monitor the Conformational Dynamics of NBD1 in Cystic Fibrosis . (massspec.com)
- Hydrogen Deuterium Exchange Mass Spectrometry of Oxygen Sensitive Proteins , Bio-protocol 8, no. 6 (2018). (massspec.com)
- Elucidation of tRNA-cytochrome c interactions through hydrogen/deuterium exchange mass spectrometry , Biochimica et Biophysica Acta (BBA)-Proteins and Proteomics 1865.5 (2017): 539-546. (massspec.com)
- Conformational dynamics and interactions of membrane proteins by hydrogen/deuterium mass spectrometry , Heterologous Expression of Membrane Proteins . (massspec.com)
- We have previously applied hydrogen exchange (HX) mass spectrometry (MS) to membrane proteins7-14 primarily using liposomes or nanodiscs as the membrane mimetic. (tech-strategy.org)
- Currently, identification of compounds is usually based on the measurement of the accurate mass and fragmentation spectrum, chromatographic elution time, and collisional cross section. (bgu.ac.il)
- In native MS mode 14 , mass measurements enable the separation of signals originating from oligomers of different order (i.e., of different molecular mass). (nature.com)
- When a solvent exchange event occurs, the protein's hydrogen atom is swapped for deuterium, and thus the mass of the amino acid is altered. (ukri.org)
- Hydrogen Deuterium Exchange Mass Spectrometry (HDX-MS) is a technique which now firmly embedded within the biosciences. (ukri.org)
Drawbacks1
- The conventional methods for the synthesis of deuterated compounds utilize D 2 gas as the deuterium source, however, they have drawbacks. (thalesnano.com)
Reaction5
- Hydrogen-deuterium exchange (also called H-D or H/D exchange) is a chemical reaction in which a covalently bonded hydrogen atom is replaced by a deuterium atom, or vice versa. (wikipedia.org)
- The exchange reaction can be followed using a variety of methods (see Detection). (wikipedia.org)
- The H/D exchange reaction can also be catalysed, by acid, base or metal catalysts such as platinum. (wikipedia.org)
- However, some methods of deuteration analysis for molecules such as proteins, are performed in aqueous solution, which means that exchange will continue at a slow rate even after the reaction is quenched. (wikipedia.org)
- Deuterium-labeled compounds provide a way to investigate reaction pathways and mechanisms. (thalesnano.com)
Hydrogens1
- HDX-MS, on the other hand, provides an extremely sensitive method for interrogating the conformational dynamics of proteins and their complexes via monitoring the exchange of hydrogens to deuterium [ 17-19 ]. (silverchair.com)
Physiological1
- Usually exchange is performed at physiological pH (7.0-8.0) where proteins are in their most native ensemble of conformational states. (wikipedia.org)
Backbone1
- The rate of this exchange is inextricably linked to the structural environment of that amino acid on the polypeptide backbone. (ukri.org)
Reproducibility1
- process was equal to deuterium recovery in conventional answer HX MS. The reproducibility of the measurements was high despite the requirement of generating a new Org 27569 monolayer for each deuterium labeling time. (tech-strategy.org)
Molecule1
- The deuteration pattern of a molecule that has undergone H/D exchange can be maintained in aprotic environments. (wikipedia.org)
Accurate2
- Accurate measurements of deuterium alpha line emissions play an important role in determining many plasma parameters, including neutral particle density, electron source rate, particle confinement time, diffusion rate, and thermal conductivity. (aps.org)
- The pH effect on the method of ruggedness testing determined that pre-PhMA is stable across the normal human urine pH range and that neutral conditions must be maintained throughout quantification for robust and accurate measurement of urinary pre-PhMA concentrations. (cdc.gov)
Membrane Proteins2
- Keywords: Arf-1 deuterium melittin dynamics membrane Membrane proteins are involved in many cellular processes ranging from regulation recognition metabolism transport and signaling1. (tech-strategy.org)
- The major obstacle to structural characterization of membrane proteins is usually often the membrane itself which is generally not compatible with structural studies and many biophysical measurements. (tech-strategy.org)
Isotopic3
- A new experimental technique, called Differential Isotopic Analysis (D.I.A.), has been developed which allows the isotopic exchange characteristics of water in different sites in hydrous silica to be determined. (caltech.edu)
- Calcitic Crinoid fragments in a chert nodule from the Mississippian Burlington limestone yielded an oxygen isotopic temperature of 25°C, indicating that fossil fragments encased within chert nodules may be protected from post-depositional exchange with ground waters and thus suitable for isotopic paleo-temperature analysis. (caltech.edu)
- Significant isotopic effects associated with deuterium labeling often causes the deuterated IS to elute at a different retention time from the target analyte, diminishing its capability to compensate for matrix effects. (cdc.gov)
Molecules3
- Hence, the observation of H-D exchange reactions provides the first indirect evidence of catalytic activity of PAH molecules in molecular hydrogen formation [Thrower et al. (europa.eu)
- Deuterium-labeled molecules enable researchers to trace the metabolism, absorption, distribution, and elimination of compounds accurately. (thalesnano.com)
- The relevance of water exchange kinetics is underscored by recent crystallographic ®ndings of substantial variations in the number and locations of internal water molecules during the photocycle. (lu.se)
Magnetic6
- Rapid measurements of curcumin from complex samples coupled with magnetic biocompatibility molecularly imprinted polymer using electrochemical detection. (uchicago.edu)
- 4. Z. Luz and B.L. Silver, The acid catalyzed exchange of phosphorus bonded hydrogen in aqueous solutions of dialkyl phosphonates studied by nuclear magnetic resonances. (weizmann.ac.il)
- 7. M. Sheinblatt and Z. Luz, Hydrogen exchange in benzylmercaptan studied by nuclear magnetic resonance. (weizmann.ac.il)
- 19. I. Pecht and Z. Luz, Oxygen exchange between periodate and water studied by 17O nuclear magnetic resonance. (weizmann.ac.il)
- 22. Z. Luz and B.L. Silver, The acid catalyzed oxygen exchange of acetyl-acetone in dioxane-water solution measured by oxygen-17 nuclear magnetic resonance. (weizmann.ac.il)
- 24. Z. Luz and I. Pecht, Oxygen-17 nuclear magnetic resonance and oxygen exchange in aqueous solutions of telluric acid. (weizmann.ac.il)
Dynamics1
- When coupled with hydrogen deuterium exchange (HDX), in solution or gas phase, MS provides insight into the structural dynamics of different oligomeric forms. (nature.com)
Reactions5
- Our measurements show evidence of such exchange reactions. (europa.eu)
- Furthermore, our study illustrates that measurements based on using the precipitation waters' inherent low electrical conductivity can be significantly biased by water-sediment reactions. (ufz.de)
- The batch study and reactive transport simulations confirmed this observation while revealing mineral reactions and, to a minor extent, also ion exchange as the underlying processes. (ufz.de)
- Other approaches have been employed to overcome the difficulties, such as catalytic H-D exchange reactions between H 2 and D 2 O. These methods are usually time consuming, they do not produce high purity D 2 and require high pressure, special catalyst or excess amount of a strong base or acid. (thalesnano.com)
- These instruments are capable of generating deuterium gas from the electrolysis of D 2 O with 99,98% purity, which can be used safely and easily in continuous flow reactions. (thalesnano.com)
Neutral3
- The measurements reported here provide the first direct observation of superhydrogenation of neutral PAHs by H atom addition [Thrower et al. (europa.eu)
- A simple model was developed to reconstruct the outer-midplane neutral density based on Thomson scattering data for the electron density and temperature, and on measurements of deuterium-alpha emission from edge neutrals. (ukaea.uk)
- The neutral density reconstructed using the simple model is found to qualitatively agree with SOLPS-ITER modelling and to yield a synthetic passive FIDA signal that is consistent with measurement. (ukaea.uk)
Catalyst1
- It can be applied most easily to exchangeable protons and deuterons, where such a transformation occurs in the presence of a suitable deuterium source, without any catalyst. (wikipedia.org)
Proteins1
- The theoretical framework for understanding hydrogen exchange in proteins was first described by Kaj Ulrik Linderstrøm-Lang and he was the first to apply H/D exchange to study proteins. (wikipedia.org)
Water2
- values of successively driven-off samples varies markedly, depending on the degree to which the water in silica has been exchanged with deuterium-rich water in controlled experiments. (caltech.edu)
- Seasonal changes in the background levels of deuterium and oxygen-18 in the body water of four captive harp seals and in the freshwater pool in which they were kept were measured over a time period of 1 year. (biologists.com)
Protons1
- In protic solution exchangeable protons such as those in hydroxyl or amine group exchange protons with the solvent. (wikipedia.org)
Chemical2
- He was also interested in paleotemperature measurements, inquiries into the genesis of planets, and the chemical difficulties of the earth's origin. (thescandoreview.com)
- For the discovery of deuterium, Urey received the Nobel Prize in Chemistry in 1934 and the Willard Gibbs Medal from the American Chemical Society's Chicago Section. (thescandoreview.com)
Signals2
- When coupled with ion mobility (IM-MS), the technique also allows the separation of signals from different structural variants of oligomers of the same order and measurement of their collisional cross section (Ω, Å 2 ). (nature.com)
- 2 Hz) and well-dispersed 13 C signals, the deuterium-induced shift difference of 0.11 ppm for the protonated and deprotonated ζ -amino groups, which corresponds to 16.5 Hz at a field strength of 14 T (150 MHz for 13 C), could be accurately measured. (copernicus.org)
Electron1
- Bremsstrahlung from the California Institute of Technology electron synchrotron was incident on a liquid deuterium target. (caltech.edu)
Flow1
- Pressure-driven laminar flow switching for rapid exchange of solution environment around surface adhered biological particles. (harvard.edu)
Reliability1
- By using deuterium-labeled compounds as internal standards, researchers can increase the accuracy and reliability of their measurements, providing precise identification and quantification of the target compounds. (thalesnano.com)
Density1
- H-D exchange was measured originally by the father of hydrogen exchange Kaj Ulrik Linderstrøm-Lang using density gradient tubes. (wikipedia.org)
Compounds1
- Deuterium-labeled compounds have an important role as valuable research tools in the field of chemistry. (thalesnano.com)
Rapid1
- Rapid and abrupt changes in the background levels of deuterium and oxygen-18 may complicate calculation of energy expenditure by use of the DLW method. (biologists.com)
Target1
- We are very grateful to Mr. Earl Emery for the maintenance of the liquid deuterium target and to Alfred Neubieser, Lawrence Loucks, Daniel Sell, and the crew of the Caltech synchrotron for the efficient operation of the machine. (caltech.edu)
Method2
- In 1931, he created a method for fractional distillation of liquid hydrogen to concentrate any probable heavy hydrogen isotopes, which led to the discovery of deuterium. (thescandoreview.com)
- This work describes a quantitative high-throughput analytical method for the simultaneous measurement of small aliphatic nitrogenous biomarkers, i.e., 1,6-hexamethylenediamine (HDA), isophoronediamine (IPDA), beta-methylamino-l-alanine (BMAA), and trimethylamine N-oxide (TMAO), in human urine. (cdc.gov)
Researchers1
- Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. (stackexchange.com)
Results2
- A forward peak is observed, which is estimated (from results of other experiments) to be considerably smaller than that for np charge exchange. (caltech.edu)
- Bias - a systematic distortion of measurements that makes the results inaccurate. (cdc.gov)
Technique4
- Dans une première partie, l'utilisation de cette technique pour la détection de complexes protéiques intacts a été développée sur le système constitué de la créatine kinase (CK) et de ses ligands ADP et ATP, conduisant à l'observation de ces complexes en phase gazeuse. (hal.science)
- 2. Examine the applicability and validity of the Bioelectrical Impendence Vector Analysis (BIVA) in estimating BF against the deuterium dilution technique among adolescents in the region. (who.int)
- 1. In brief, the deuterium dilution technique will be performed on the participants aged 15=18 years. (who.int)
- Body fat is determined using the deuterium dilution technique. (who.int)
Solution1
- Dans une seconde partie, des techniques pour l'étude de l'accessibilité de surface de complexes de protéines par modification chimique en solution, aussi bien réversibles (échanges H/D) qu'irréversibles (modification spécifique d'histidine et de lysine par le DEPC) ont été mises au point et appliquées. (hal.science)
High1
- In the past rather extensive counter measurements(1) of this cross section have been made at high energies and low momentum transfers, but little counter data exist at large momentum transfer. (caltech.edu)