Metals, Rare Earth
Europium
Luminescent Measurements
Formycins
Ytterbium
Energy Transfer
Lanthanoid Series Elements
Calbindin 1
Picolinic Acids
Terbium
Luminescence
Lanthanum
S100 Calcium Binding Protein G
Chelating Agents
Binding Sites
Fluorescence Resonance Energy Transfer
Calmodulin
Tryptophan
Fluorescent Dyes
Calcium-Binding Proteins
Calcium
Models, Theoretical
Molecular Structure
Protein Conformation
Molecular Sequence Data
Hydrogen-Ion Concentration
Protein Binding
Amino Acid Sequence
Potassium ion efflux induced by cationic compounds in yeast. (1/202)
Potassium efflux in yeast induced by several cationic compounds showed different characteristics. All of the observed efflux required glucose as substrate at the concentrations used. For most of them, the phenomenon required binding of the cationic compound to the cell surface and increased with the negative cell surface charge, and for all the compounds tested, it depended on a metabolizable substrate. Efflux induced with terbium chloride appeared more likely due to the function of a K+/H+ antiporter. With DEAE-dextran and dihydrostreptomycin, potassium efflux was dependent on the cell potassium content and was also sensitive to osmotic changes of the medium. DEAE-dextran-provoked efflux was not due to cell disruption. Dihydrostreptomycin seemed to activate a potassium efflux system which could not be studied in isolation, but its inhibition of potassium uptake may also be involved. Except for cells treated with ethidium bromide, no appreciable cell disruption was observed. The potassium efflux observed appears to be a membrane phenomenon reversible after washing with magnesium chloride. (+info)Terbium and rhodamine as labels in a homogeneous time-resolved fluorometric energy transfer assay of the beta subunit of human chorionic gonadotropin in serum. (2/202)
BACKGROUND: Fluorescence resonance energy transfer (FRET) is a powerful tool in analytical chemistry. The aim of the present work was to use FRET to design a homogeneous immunoassay. METHODS: We used a highly fluorescent terbium (Tb3+) chelate (donor) and the organic fluorochrome rhodamine (acceptor) combined with time-resolved detection of the acceptor emission in homogeneous assay format for the measurement of the beta subunit of human chorionic gonadotropin (betahCG) in serum. We used two antibodies labeled with Tb3+ and rhodamine, respectively, recognizing different epitopes on betahCG. The close proximity between the labels in the immunocomplex permitted energy transfer between the pulse-excited Tb3+ donor (decay time >1 ms) and the acceptor rhodamine (decay time of 3.0 ns). The prolonged emission of donor-excited acceptor (energy transfer) was measured after the short-lived background and acceptor emissions had decayed. The emission of donor-excited rhodamine was measured at a wavelength of where the emission of unbound donor is minimal. RESULTS: The energy transfer signal was directly proportional to the betahCG concentration in the sample. The limit of detection was 0.43 microgram/L, and the assay was linear up to 200 microgram/L. Total assay imprecision in the range 10-185 microgram/L was between 7.5% and 2.8%. CONCLUSIONS: Although less sensitive than heterogeneous, dissociation-enhanced europium-based separation assays, the presented assay format has advantages such as speed and simplicity, which make the assay format ideal for assays requiring a high throughput. (+info)Different cation binding to the I domains of alpha1 and alpha2 integrins: implication of the binding site structure. (3/202)
In the present work, we studied the interactions of recombinant alpha1 and alpha2 integrin I domains with cations Tb(3+), Mn(2+), Mg(2+) and Ca(2+). We observed that alpha1 and alpha2 I domains bind these cations with significantly different characteristics. The binding of Mg(2+) by the alpha1 I domain was accompanied by significant changes of tryptophan fluorescence which could be interpreted as a conformational change. Comparison of the alpha1 integrin I domain structure obtained by comparative modeling with a known structure of the alpha2 integrin I domain shows distinct differences in the metal ion binding sites which could explain the differences in cation binding. (+info)NMR approaches for monitoring domain orientations in calcium-binding proteins in solution using partial replacement of Ca2+ by Tb3+. (4/202)
This work shows that the partial replacement of diamagnetic Ca2+ by paramagnetic Tb3+ in Ca2+/calmodulin systems in solution allows the measurement of interdomain NMR pseudocontact shifts and leads to magnetic alignment of the molecule such that significant residual dipolar couplings can be measured. Both these parameters can be used to provide structural information. Species in which Tb3+ ions are bound to only one domain of calmodulin (the N-domain) and Ca2+ ions to the other (the C-domain) provide convenient systems for measuring these parameters. The nuclei in the C-domain experience the local magnetic field induced by the paramagnetic Tb3+ ions bound to the other domain at distances of over 40 A from the Tb3+ ion, shifting the resonances for these nuclei. In addition, the Tb3+ ions bound to the N-domain of calmodulin greatly enhance the magnetic susceptibility anisotropy of the molecule so that a certain degree of alignment is produced due to interaction with the external magnetic field. In this way, dipolar couplings between nuclear spins are not averaged to zero due to solution molecular tumbling and yield dipolar coupling contributions to, for example, the one-bond 15N-1H splittings of up to 17 Hz in magnitude. The degree of alignment of the C-domain will also depend on the degree of orientational freedom of this domain with respect to the N-domain containing the Tb3+ ions. Pseudocontact shifts for NH groups and 1H-15N residual dipolar couplings for the directly bonded atoms have been measured for calmodulin itself, where the domains have orientational freedom, and for the complex of calmodulin with a target peptide from skeletal muscle myosin light chain kinase, where the domains have fixed orientations with respect to each other. The simultaneous measurements of these parameters for systems with domains in fixed orientations show great potential for the determination of the relative orientation of the domains. (+info)Probing the binding of Tb(III) and Eu(III) to the hammerhead ribozyme using luminescence spectroscopy. (5/202)
BACKGROUND: Divalent metal ions serve as structural as well as catalytic cofactors in the hammerhead ribozyme reaction. The natural cofactor in these reactions is Mg(II), but its spectroscopic silence makes it difficult to study. We previously showed that a single Tb(III) ion inhibits the hammerhead ribozyme by site-specific competition for a Mg(II) ion and therefore can be used as a spectroscopic probe for the Mg(II) it replaces. RESULTS: Lanthanide luminescence spectroscopy was used to study the coordination environment around Tb(III) and Eu(III) ions bound to the structurally well-characterized site on the hammerhead ribozyme. Sensitized emission and direct excitation experiments show that a single lanthanide ion binds to the ribozyme under these conditions and that three waters of hydration are displaced from the Tb(III) upon binding the RNA. Furthermore, we show that these techniques allow the comparison of binding affinities for a series of ions to this site. The binding affinities for ions at the G5 site correlates linearly with the function Z(2)/r of the aqua ion (where Z is the charge and r is the radius of the ion). CONCLUSIONS: This study compares the crystallographic nature of the G5 metal-binding site with solution measurements and gives a clearer picture of the coordination environment of this ion. These results provide one of the best characterized metal-binding sites from a ribozyme, so we use this information to compare the RNA site with that of typical metalloproteins. (+info)Energy transfer between terbium (III) and cobalt (II) in thermolysin: a new class of metal--metal distance probes. (6/202)
The visible fluorescence of terbium(III) when bound to a calcium binding site of thermolysin is greatly enhanced with an excitation maximum at 280 nm but substitution of cobalt(II) for zinc at the active site decreases the intensity by 89.5%. Treatment with N-bromosuccinimide quenches enzyme tryptophan and Tb(III) fluorescence to a similar extent and suggests the operation of tryptophan vector Tb(III) vector Co(II) energy relay system in the enzyme. Dipoledipole radiationless energy transfer between the Tb(III) donor and the Co(II) acceptor can account for this quenching. The inherent characteristics of the metal pair limits the value of the orientation factor, K2, of the Forster equation, thereby reducing uncertainties in distance measurements by energy transfer compared with other systems. A quantum yield of 0.51 yields a value of R0, the distance for 50% energy transfer, of 19.6 A, and a distance, R, between Tb(III) and Co(II) of 13.7 A, a value identical to that measured for the distance between the active site zinc atom and calcium atom number 1 by x-ray analysis in native thermolysin crystals. The limits of confidence of this measurement are discussed. Energy transfer between two different metal atom sites of a protein provides a new class of probes to measure intramolecular distances of biological macromolecules in solution. (+info)Mg2+-independent hairpin ribozyme catalysis in hydrated RNA films. (7/202)
The hairpin ribozyme catalyzes RNA cleavage in partially hydrated RNA films in the absence of added divalent cations. This reaction exhibits the characteristics associated with the RNA cleavage reaction observed under standard conditions in solution. Catalysis is a site-specific intramolecular transesterification reaction, requires the 2'-hydroxyl group of substrate nucleotide A(-1), and generates 2',3'-cyclic phosphate and 5'-hydroxyl termini. Mutations in both ribozyme and substrate abolish catalysis in hydrated films. The reaction is accelerated by cations that may enhance binding, conformational stability, and catalytic activity, and is inhibited by Tb3+. The reaction has an apparent temperature optimum of 4 degrees C. At this temperature, cleavage is slow (k(obs): 2 d(-1)) and progressive, with accumulation of cleavage products to an extent of 40%. The use of synthetic RNAs, chelators, and analysis of all reaction components by inductively coupled plasma-optical spectrophotometry (ICPOES) effectively rules out the possibility of contaminating divalent metals in the reactions. Catalysis is minimal under conditions of extreme dehydration, indicating that the reaction requires hydration of RNA by atmospheric water. Our results provide a further caution for those studying the biochemical activity of ribozymes in vitro and in cells, as unanticipated catalysis could occur during RNA manipulation and lead to misinterpretation of data. (+info)An interdomain distance in cardiac troponin C determined by fluorescence spectroscopy. (8/202)
The distance between Ca2+-binding site III in the C-terminal domain and Cys35 in the N-terminal domain in cardiac muscle troponin C (cTnC) was determined with a single-tryptophan mutant using bound Tb3+ as the energy donor and iodoacetamidotetramethylrhodamine linked to the cysteine residue as energy acceptor. The luminescence of bound Tb3+ was generated through sensitization by the tryptophan located in the 12-residue binding loop of site III upon irradiation at 295 nm, and this sensitized luminescence was the donor signal transferred to the acceptor. In the absence of bound cation at site II, the mean interdomain distance was found to be 48-49 A regardless of whether the cTnC was unbound or bound to cardiac troponin I, or reconstituted into cardiac troponin. These results suggest that cTnC retains its overall length in the presence of bound target proteins. The distribution of the distances was wide (half-width >9 A) and suggests considerable interdomain flexibility in isolated cTnC, but the distributions became narrower for cTnC in the complexes with the other subunits. In the presence of bound cation at the regulatory site II, the interdomain distance was shortened by 6 A for cTnC, but without an effect on the half-width. The decrease in the mean distance was much smaller or negligible when cTnC was complexed with cTnI or cTnI and cTnT under the same conditions. Although free cTnC has considerable interdomain flexibility, this dynamics is slightly reduced in troponin. These results indicate that the transition from the relaxed state to an activated state in cardiac muscle is not accompanied by a gross alteration of the cTnC conformation in cardiac troponin. (+info)Rare earth metals, also known as rare earth elements, are a group of 17 metallic elements found in the periodic table. They include:
1. Lanthanum (La)
2. Cerium (Ce)
3. Praseodymium (Pr)
4. Neodymium (Nd)
5. Promethium (Pm)
6. Samarium (Sm)
7. Europium (Eu)
8. Gadolinium (Gd)
9. Terbium (Tb)
10. Dysprosium (Dy)
11. Holmium (Ho)
12. Erbium (Er)
13. Thulium (Tm)
14. Ytterbium (Yb)
15. Lutetium (Lu)
1
I apologize for any confusion, but "Europium" is not a medical term. It is a chemical element with the symbol "Eu" and atomic number 63 on the periodic table. Europium is a rare earth metal that is used in various applications such as fluorescent lamps, glass additives, and phosphors in television tubes and plasma displays.
If you have any medical questions or terms, I would be happy to help you with those!
Luminescent measurements refer to the quantitative assessment of the emission of light from a substance that has been excited, typically through some form of energy input such as electrical energy or radiation. In the context of medical diagnostics and research, luminescent measurements can be used in various applications, including bioluminescence imaging, which is used to study biological processes at the cellular and molecular level.
Bioluminescence occurs when a chemical reaction produces light within a living organism, often through the action of enzymes such as luciferase. By introducing a luciferase gene into cells or organisms, researchers can use bioluminescent measurements to track cellular processes and monitor gene expression in real time.
Luminescent measurements may also be used in medical research to study the properties of materials used in medical devices, such as LEDs or optical fibers, or to develop new diagnostic tools based on light-emitting nanoparticles or other luminescent materials.
In summary, luminescent measurements are a valuable tool in medical research and diagnostics, providing a non-invasive way to study biological processes and develop new technologies for disease detection and treatment.
Formycins are a group of antibiotics that are derived from certain strains of Streptomyces bacteria. They include formycin B (also known as pyrazofurin), which is an antiviral and antimetabolite drug that works by interfering with the production of genetic material in cells. Formycins are not widely used in clinical medicine due to their potential toxicity and the availability of other effective antibiotics and antiviral drugs.
Fluorescence spectrometry is a type of analytical technique used to investigate the fluorescent properties of a sample. It involves the measurement of the intensity of light emitted by a substance when it absorbs light at a specific wavelength and then re-emits it at a longer wavelength. This process, known as fluorescence, occurs because the absorbed energy excites electrons in the molecules of the substance to higher energy states, and when these electrons return to their ground state, they release the excess energy as light.
Fluorescence spectrometry typically measures the emission spectrum of a sample, which is a plot of the intensity of emitted light versus the wavelength of emission. This technique can be used to identify and quantify the presence of specific fluorescent molecules in a sample, as well as to study their photophysical properties.
Fluorescence spectrometry has many applications in fields such as biochemistry, environmental science, and materials science. For example, it can be used to detect and measure the concentration of pollutants in water samples, to analyze the composition of complex biological mixtures, or to study the properties of fluorescent nanomaterials.
I'm sorry for any confusion, but "Ytterbium" is not a medical term. It is a chemical element with the symbol "Yb" and atomic number 70. Ytterbium is a rare earth metal that is silvery white, soft, malleable, and has many uses in scientific research, particularly in the field of laser technology.
If you have any medical questions or terms you would like me to define, please let me know!
"Energy transfer" is a general term used in the field of physics and physiology, including medical sciences, to describe the process by which energy is passed from one system, entity, or location to another. In the context of medicine, energy transfer often refers to the ways in which cells and organ systems exchange and utilize various forms of energy for proper functioning and maintenance of life.
In a more specific sense, "energy transfer" may refer to:
1. Bioenergetics: This is the study of energy flow through living organisms, including the conversion, storage, and utilization of energy in biological systems. Key processes include cellular respiration, photosynthesis, and metabolic pathways that transform energy into forms useful for growth, maintenance, and reproduction.
2. Electron transfer: In biochemistry, electrons are transferred between molecules during redox reactions, which play a crucial role in energy production and consumption within cells. Examples include the electron transport chain (ETC) in mitochondria, where high-energy electrons from NADH and FADH2 are passed along a series of protein complexes to generate an electrochemical gradient that drives ATP synthesis.
3. Heat transfer: This is the exchange of thermal energy between systems or objects due to temperature differences. In medicine, heat transfer can be relevant in understanding how body temperature is regulated and maintained, as well as in therapeutic interventions such as hyperthermia or cryotherapy.
4. Mechanical energy transfer: This refers to the transmission of mechanical force or motion from one part of the body to another. For instance, muscle contractions generate forces that are transmitted through tendons and bones to produce movement and maintain posture.
5. Radiation therapy: In oncology, ionizing radiation is used to treat cancer by transferring energy to malignant cells, causing damage to their DNA and leading to cell death or impaired function.
6. Magnetic resonance imaging (MRI): This non-invasive diagnostic technique uses magnetic fields and radio waves to excite hydrogen nuclei in the body, which then release energy as they return to their ground state. The resulting signals are used to generate detailed images of internal structures and tissues.
In summary, "energy transfer" is a broad term that encompasses various processes by which different forms of energy (thermal, mechanical, electromagnetic, etc.) are exchanged or transmitted between systems or objects in the context of medicine and healthcare.
The Lanthanoid series, also known as the lanthanides, refers to the 15 metallic chemical elements in the periodic table that make up row 6 of the f-block. These elements include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).
These elements are characterized by having similar properties, including being soft, silvery-white, highly reactive, and divalent or trivalent in their chemical behavior. They have incompletely filled f orbitals, which results in unique magnetic and optical properties that make them useful in various applications, such as magnets, batteries, and phosphors.
The lanthanoid series elements are often extracted from minerals such as monazite and bastnasite, and their production involves complex chemical processes to separate them from each other. Due to their similar properties, this separation can be challenging and requires significant expertise and resources.
Calbindin 1 is a calcium-binding protein that belongs to the family of EF-hand proteins. It is also known as calbindin D-28k, due to its molecular weight of approximately 28 kilodaltons. This protein is widely distributed in various tissues and organisms but is particularly abundant in the nervous system, where it plays crucial roles in calcium homeostasis, neuroprotection, and signal transduction.
In neurons, calbindin 1 is primarily located in the cytoplasm and dendrites, with lower concentrations found in the axons and nerve terminals. It helps regulate intracellular calcium levels by binding to calcium ions (Ca2+) with high affinity and capacity, thereby preventing rapid fluctuations in Ca2+ concentration that could trigger cellular damage or dysfunction.
Calbindin 1 has been implicated in several neuronal processes, including neurotransmitter release, synaptic plasticity, and neuronal excitability. Additionally, it is believed to provide neuroprotection against various insults, such as oxidative stress, glutamate excitotoxicity, and calcium overload, which are associated with neurological disorders like Alzheimer's disease, Parkinson's disease, and epilepsy.
In summary, calbindin 1 is a calcium-binding protein that plays essential roles in maintaining calcium homeostasis, neuroprotection, and neuronal signaling within the nervous system.
Picolinic acid is not specifically classified as a medical term, but it is a type of organic compound that belongs to the class of molecules known as pyridinecarboxylic acids. These are carboxylic acids derived from pyridine by the substitution of a hydrogen atom with a carboxyl group.
Picolinic acid, specifically, is a pyridine derivative with a carboxyl group at the 2-position of the ring. It is naturally produced in the body and can be found in various tissues and fluids, including the brain, where it plays a role in the metabolism of amino acids, particularly tryptophan.
In addition to its physiological functions, picolinic acid has been studied for its potential therapeutic applications. For example, it has been shown to have antibacterial and antifungal properties, and may also play a role in heavy metal chelation and neuroprotection. However, more research is needed to fully understand the medical significance of this compound.
Terbium is not a medical term, but a chemical element. It is a rare earth element with the symbol Tb and atomic number 65. It is soft, silvery-white, and has a metallic shine. Terbium is not used in medicine to treat or diagnose diseases directly. However, it does have some applications in medical technology such as in doping materials for magnetic resonance imaging (MRI) machines and in the creation of high-intensity gas discharge lamps that are used in medical lighting.
Luminescence is not a term that has a specific medical definition. However, in general terms, luminescence refers to the emission of light by a substance that has absorbed energy. This phenomenon can occur in some medical contexts, such as in medical imaging techniques like bioluminescence imaging (BLI) and chemiluminescence immunoassays (CLIA).
In BLI, genetically modified organisms or cells are used to produce light at specific wavelengths that can be detected and measured. This technique is often used in preclinical research to study biological processes such as gene expression, cell proliferation, and metastasis.
In CLIA, an enzymatic reaction produces light that is used to detect and quantify the presence of a specific analyte or target molecule. This technique is commonly used in clinical laboratories for the detection of various biomarkers, such as hormones, drugs, and infectious agents.
Therefore, while luminescence is not a medical term per se, it has important applications in medical research and diagnostics.
Lanthanum is not a medical term itself, but it is a chemical element with the symbol "La" and atomic number 57. It is a soft, ductile, silvery-white metal that belongs to the lanthanide series in the periodic table.
However, in medical contexts, lanthanum may be mentioned as a component of certain medications or medical devices. For example, lanthanum carbonate (trade name Fosrenol) is a medication used to treat hyperphosphatemia (elevated levels of phosphate in the blood) in patients with chronic kidney disease. Lanthanum carbonate works by binding to phosphate in the gastrointestinal tract, preventing its absorption into the bloodstream.
It is important to note that lanthanum compounds are not biologically active and do not have any specific medical effects on their own. Any medical uses of lanthanum are related to its physical or chemical properties, rather than its biological activity.
S100 calcium binding protein G, also known as calgranulin A or S100A8, is a member of the S100 family of proteins. These proteins are characterized by their ability to bind calcium ions and play a role in intracellular signaling and regulation of various cellular processes.
S100 calcium binding protein G forms a heterodimer with S100 calcium binding protein B (S100A9) and is involved in the inflammatory response, immune function, and tumor growth and progression. The S100A8/A9 heterocomplex has been shown to play a role in neutrophil activation and recruitment, as well as the regulation of cytokine production and cell proliferation.
Elevated levels of S100 calcium binding protein G have been found in various inflammatory conditions, such as rheumatoid arthritis, Crohn's disease, and psoriasis, as well as in several types of cancer, including breast, lung, and colon cancer. Therefore, it has been suggested that S100 calcium binding protein G may be a useful biomarker for the diagnosis and prognosis of these conditions.
Chelating agents are substances that can bind and form stable complexes with certain metal ions, preventing them from participating in chemical reactions. In medicine, chelating agents are used to remove toxic or excessive amounts of metal ions from the body. For example, ethylenediaminetetraacetic acid (EDTA) is a commonly used chelating agent that can bind with heavy metals such as lead and mercury, helping to eliminate them from the body and reduce their toxic effects. Other chelating agents include dimercaprol (BAL), penicillamine, and deferoxamine. These agents are used to treat metal poisoning, including lead poisoning, iron overload, and copper toxicity.
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.
Fluorescence Resonance Energy Transfer (FRET) is not strictly a medical term, but it is a fundamental concept in biophysical and molecular biology research, which can have medical applications. Here's the definition of FRET:
Fluorescence Resonance Energy Transfer (FRET) is a distance-dependent energy transfer process between two fluorophores, often referred to as a donor and an acceptor. The process occurs when the emission spectrum of the donor fluorophore overlaps with the excitation spectrum of the acceptor fluorophore. When the donor fluorophore is excited, it can transfer its energy to the acceptor fluorophore through non-radiative dipole-dipole coupling, resulting in the emission of light from the acceptor at a longer wavelength than that of the donor.
FRET efficiency depends on several factors, including the distance between the two fluorophores, their relative orientation, and the spectral overlap between their excitation and emission spectra. FRET is typically efficient when the distance between the donor and acceptor is less than 10 nm (nanometers), making it a powerful tool for measuring molecular interactions, conformational changes, and distances at the molecular level.
In medical research, FRET has been used to study various biological processes, such as protein-protein interactions, enzyme kinetics, and gene regulation. It can also be used in developing biosensors for detecting specific molecules or analytes in clinical samples, such as blood or tissue.
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.
Calmodulin is a small, ubiquitous calcium-binding protein that plays a critical role in various intracellular signaling pathways. It functions as a calcium sensor, binding to and regulating the activity of numerous target proteins upon calcium ion (Ca^2+^) binding. Calmodulin is expressed in all eukaryotic cells and participates in many cellular processes, including muscle contraction, neurotransmitter release, gene expression, metabolism, and cell cycle progression.
The protein contains four EF-hand motifs that can bind Ca^2+^ ions. Upon calcium binding, conformational changes occur in the calmodulin structure, exposing hydrophobic surfaces that facilitate its interaction with target proteins. Calmodulin's targets include enzymes (such as protein kinases and phosphatases), ion channels, transporters, and cytoskeletal components. By modulating the activity of these proteins, calmodulin helps regulate essential cellular functions in response to changes in intracellular Ca^2+^ concentrations.
Calmodulin's molecular weight is approximately 17 kDa, and it consists of a single polypeptide chain with 148-150 amino acid residues. The protein can be found in both the cytoplasm and the nucleus of cells. In addition to its role as a calcium sensor, calmodulin has been implicated in various pathological conditions, including cancer, neurodegenerative diseases, and cardiovascular disorders.
Tryptophan is an essential amino acid, meaning it cannot be synthesized by the human body and must be obtained through dietary sources. Its chemical formula is C11H12N2O2. Tryptophan plays a crucial role in various biological processes as it serves as a precursor to several important molecules, including serotonin, melatonin, and niacin (vitamin B3). Serotonin is a neurotransmitter involved in mood regulation, appetite control, and sleep-wake cycles, while melatonin is a hormone that regulates sleep-wake patterns. Niacin is essential for energy production and DNA repair.
Foods rich in tryptophan include turkey, chicken, fish, eggs, cheese, milk, nuts, seeds, and whole grains. In some cases, tryptophan supplementation may be recommended to help manage conditions related to serotonin imbalances, such as depression or insomnia, but this should only be done under the guidance of a healthcare professional due to potential side effects and interactions with other medications.
Fluorescent dyes are substances that emit light upon excitation by absorbing light of a shorter wavelength. In a medical context, these dyes are often used in various diagnostic tests and procedures to highlight or mark certain structures or substances within the body. For example, fluorescent dyes may be used in imaging techniques such as fluorescence microscopy or fluorescence angiography to help visualize cells, tissues, or blood vessels. These dyes can also be used in flow cytometry to identify and sort specific types of cells. The choice of fluorescent dye depends on the specific application and the desired properties, such as excitation and emission spectra, quantum yield, and photostability.
Calcium-binding proteins (CaBPs) are a diverse group of proteins that have the ability to bind calcium ions (Ca^2+^) with high affinity and specificity. They play crucial roles in various cellular processes, including signal transduction, muscle contraction, neurotransmitter release, and protection against oxidative stress.
The binding of calcium ions to these proteins induces conformational changes that can either activate or inhibit their functions. Some well-known CaBPs include calmodulin, troponin C, S100 proteins, and parvalbumins. These proteins are essential for maintaining calcium homeostasis within cells and for mediating the effects of calcium as a second messenger in various cellular signaling pathways.
Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:
Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.
Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.
Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.
The term "Theoretical Models" is used in various scientific fields, including medicine, to describe a representation of a complex system or phenomenon. It is a simplified framework that explains how different components of the system interact with each other and how they contribute to the overall behavior of the system. Theoretical models are often used in medical research to understand and predict the outcomes of diseases, treatments, or public health interventions.
A theoretical model can take many forms, such as mathematical equations, computer simulations, or conceptual diagrams. It is based on a set of assumptions and hypotheses about the underlying mechanisms that drive the system. By manipulating these variables and observing the effects on the model's output, researchers can test their assumptions and generate new insights into the system's behavior.
Theoretical models are useful for medical research because they allow scientists to explore complex systems in a controlled and systematic way. They can help identify key drivers of disease or treatment outcomes, inform the design of clinical trials, and guide the development of new interventions. However, it is important to recognize that theoretical models are simplifications of reality and may not capture all the nuances and complexities of real-world systems. Therefore, they should be used in conjunction with other forms of evidence, such as experimental data and observational studies, to inform medical decision-making.
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 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.
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.
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.
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.
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 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.
Terbium
Terbium acetylacetonate
Terbium phosphide
Terbium fluoride
Terbium compounds
Terbium acetate
Terbium oxide
Terbium(III) fluoride
Terbium(III) bromide
Terbium(III) chloride
Terbium(III) oxide
Isotopes of terbium
Terbium(III) nitrate
Terbium(III) hydroxide
Terbium(III) iodide
Terbium(IV) oxide
Terbium(III) perchlorate
Terbium gallium garnet
Terbium(IV) fluoride
Terbium(III,IV) oxide
Timeline of chemical element discoveries
Faraday effect
Ytterbium compounds
Binary compounds of silicon
Phosphor
Berkelium compounds
Mining in Japan
Allotropy
Holmium(III) iodide
Rare-earth element
Terbium - Wikipedia
Terbium | Chemistry Nexus
References and Notes for Terbium ( Tb )
Terbium Samples | AMERICAN ELEMENTS ®
Terbium Flake | AMERICAN ELEMENTS ®
Terbium/Atomic mass - Citizendium
Sample of the element Terbium in the Periodic Table
Sample of the element Terbium in the Periodic Table
Isotope data for terbium-157 in the Periodic Table
Sample of the element Terbium in the Periodic Table
Isotope data for terbium-144 in the Periodic Table
Isotope data for terbium-148 in the Periodic Table
Crystal structures of potassium terbium(III) tetrasulfidogermanate, KTbGeS4, and potassium praseodymium(III)...
Terbium Nitride The latest Qatar News,Qatar Technology,Qatar Indus
terbium | ESPI Metals ESPI Metals
Antimony, compound with terbium (1:1) | Pharos
Terbium - german nouns declensions: Singular and Plural » croDict
APS -APS March Meeting 2022
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Phospho-JNK 1/2/3 (Thr183/Tyr185) Terbium SureFire Ultra Detection Kit, 50,000 Assay Points | PerkinElmer
Terbium among the heavy elements discovered in the atmosphere of the exoplanet KELT-9b | Division of Astrophysics
CONTRIBUTIONS CONCERNING SEPARATION OF RARE EARTHS. IX. THE SYSTEMS TERBIUM OXIDE-YTTRIUM OXIDE AND TERBIUM OXIDE-ERBIUM OXIDE ...
IUCr) <span class="it"><i>catena</i></span>-Poly[[[di-aqua-terbium(III)]-<span class="symbol">μ</span>-6-carb-oxy-nicotinato-...
RADII FOR TERBIUM 140 (Z=65, N=75)
ter Bio,Wiki, Age, Height, Movies, VR videos, Links, Leaks, Pics & More - Snitch Biography & Wiki
Terbium doped Yttrium Oxide Sulfide Nanopowder (Y2O2S:Tb, APS: 50-80nm,Purity: 99.9%)
High magnetic field properties of gadolinium, terbium, and holmium.
Terbium Chloride TbCl3
Terbium Target Terbium
Nitride7
- They were trying to encapsulate terbium atoms within fullerenes but instead encapsulated terbium nitride within an egg-shaped fullerene. (webelements.com)
- TbN is an acronym for Terbium Nitride. (actionext.com)
- Terbium nitride is a black powder with a molar mass of 172.93g·mol-1. (tungstenmolybdenummetals.de)
- Terbium nitride has a high melting point, but poor oxidation resistance. (tungstenmolybdenummetals.de)
- Our terbium nitride TbN powder (CAS 13708-63-9) is with high purity, ultrafine particle size, bigger surface area. (tungstenmolybdenummetals.de)
- Terbium nitride TbN powder is used for high-end electronics, specialty materials, etc. (tungstenmolybdenummetals.de)
- We have many different kinds of packing which depend on the terbium nitride TbN powder quantity. (tungstenmolybdenummetals.de)
Rare earths1
- As with other rare earths, terbium metal is produced by reducing the anhydrous chloride or fluoride with calcium metal. (espimetals.com)
Oxide5
- Terbium oxide is used in fluorescent lamps and television and monitor cathode-ray tubes (CRTs). (wikipedia.org)
- 2 Tb (s) + 3 H2SO4 → 2 Tb3+ + 3 SO2−4 + 3 H2↑ 2 Tb + 3 X2 → 2 TbX3 (X = F, Cl, Br, I) 2 Tb (s) + 6 H2O → 2 Tb(OH)3 + 3 H2↑ Terbium also oxidizes readily in air to form a mixed terbium(III,IV) oxide: 8 Tb + 7 O2 → 2 Tb4O7 The most common oxidation state of terbium is +3 (trivalent), such as TbCl 3. (wikipedia.org)
- The structural relationship of air-annealed samples of Terbium oxide-Yttrium oxide and Terbium oxide-Erbium oxide systems are discussed. (dtic.mil)
- The authors make an attempt to explain the anomaly of the lattice constants of the two systems as a function of the terbium oxide content. (dtic.mil)
- Terbium doped Yttrium Oxide Sulfide: Doping on nanomaterials provides a flexible way to tune to the properties of the materials while maintaining their high surface areas .The electronic, optical, photochemical, photo-electrochemical, photocatalytic and photoexcited relaxation properties can be tuned towards the desired direction by adding different elements.The materials can be engineered towards specific applications through careful selection of the dopants. (nanoshel.com)
Lanthanides3
- The coordination and organometallic chemistry of terbium is similar to other lanthanides. (wikipedia.org)
- Like most rare-earth elements and lanthanides, terbium is usually found in the +3 oxidation state. (wikipedia.org)
- Hazards: As with the other lanthanides, terbium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail. (espimetals.com)
Cerium3
- Like cerium and praseodymium, terbium can also form a +4 oxidation state, although it is unstable in water. (wikipedia.org)
- Yttrium Aluminium Garnet (YAG) crystal optical fiber doped with Cerium and Terbium are discussed as a possible scintillator for time-resolved radiation dosimetry. (ul.ie)
- The Cerium and Terbium co-doped YAG crystal scintillator samples are irradiated under a 6 MV photon beam from a Elekta Synergy® LINAC. (ul.ie)
Purity1
- Please use the form above to make an enquiry about Terbium chloride remembering to include the information regarding purity and the quantity you require. (absco-limited.com)
Atoms1
- Single terbium atoms have been isolated by implanting them into fullerene molecules. (wikipedia.org)
Garnet1
- For example, terbium iron garnet (TbIG) thin films have been grown by pulsed laser deposition with PMA and a T comp of ~330 K, and their spin Hall magnetoresistance and spin orbit torque switching characteristics were investigated near compensation. (aps.org)
Powder1
- Terbium nutride powder TbN is used to make high-end electronics and other specialty materials. (actionext.com)
Praseodymium2
- Chan, B. C. and Dorhout, P. K.. "Crystal structures of potassium terbium(III) tetrasulfidogermanate, KTbGeS 4 , and potassium praseodymium(III) tetraselenidogermanate, KPrGeSe 4 " Zeitschrift für Kristallographie - New Crystal Structures , vol. 220, no. 1-4, 2005, pp. 7-8. (degruyter.com)
- Chan, B. and Dorhout, P. (2005) Crystal structures of potassium terbium(III) tetrasulfidogermanate, KTbGeS 4 , and potassium praseodymium(III) tetraselenidogermanate, KPrGeSe 4 . (degruyter.com)
Labs7
- Die MapR-Hadoop-Distribution kommt bei Terbium Labs als Big-Data-Plattform für Matchlight zum Einsatz. (itsecuritynews.info)
- The post Shedding Light on the "Dark Web" with Terbium Labs appeared first on One World Identity . (libsyn.com)
- Terbium Labs announced at RSA Conference that it has raised $6.4 million in Series A financing led by .406 Ventures, bringing the total raised to $9.7 million. (helpnetsecurity.com)
- Terbium Labs will use the new capital to expand its world-class team and accelerate enterprise sales of Matchlight, a Dark Web data intelligence platform capable of finding compromised or stolen data as soon as it appears. (helpnetsecurity.com)
- Terbium Labs is redefining how security teams identify breaches and protect their organization's most critical data," said Greg Dracon, Partner at .406 Ventures and Terbium Labs board member. (helpnetsecurity.com)
- Matchlight employs a patented data fingerprinting technology that creates a one-way digital signature of any type of data, enabling companies to automatically search for their sensitive information without revealing it to anyone - not even Terbium Labs. (helpnetsecurity.com)
- Data breaches are inevitable, but the key to mitigating the damage is to detect the breach as quickly and privately as possible," said Danny Rogers, Co-Founder and CEO of Terbium Labs. (helpnetsecurity.com)
Dopant1
- Terbium is used as a dopant in calcium fluoride, calcium tungstate and strontium molybdate, materials that are used in solid-state devices, and as a crystal stabilizer of fuel cells which operate at elevated temperatures. (espimetals.com)
Chloride3
- ABSCO supplies Terbium chloride to customers in UK / Ireland on behalf of Treibacher Industrie AG. (absco-limited.com)
- ABSCO Limited is a leading supplier of Terbium chloride. (absco-limited.com)
- If you require any further information about Terbium chloride - TbCl3-6H2O please do not hesitate to contact our experienced staff. (absco-limited.com)
Compounds2
- In the solid state, tetravalent terbium is also known, in compounds such as TbO2 and TbF4. (wikipedia.org)
- A few coordination compounds containing terbium in its tetravalent state are also known. (wikipedia.org)
Oxidation2
- Most coordination and organometallic complexes contain terbium in the trivalent oxidation state. (wikipedia.org)
- However, it is possible for terbium to also be found in the 0, +1 and +2 oxidation states. (wikipedia.org)
Temperature2
- Terbium exists in two crystal allotropes with a transformation temperature of 1289 °C between them. (wikipedia.org)
- No temperature value was obtained for the boiling point of terbium trinitrate within the temperature range tested (-68°C to 600°C). (europa.eu)
Chemistry1
- chemistry), terbium, Tb, a soft silvery-gray metallic element (Tb) whose chemical compound can be used to make an activator for fluorescent materials, laser materials and insecticides and to cure some skin problems. (vny2k.com)
Crystal1
- Terbium is used to dope calcium fluoride, calcium tungstate and strontium molybdate in solid-state devices, and as a crystal stabilizer of fuel cells that operate at elevated temperatures. (wikipedia.org)
18432
- Swedish chemist Carl Gustaf Mosander discovered terbium as a chemical element in 1843. (wikipedia.org)
- The article, linked below, specifically highlights the detection of Terbium, a rare heavy metal first identified in 1843 by Swedish chemist Carl Gustaf Mosander, thereby adding a touch of historical context to this discovery. (lu.se)
Chemical1
- Terbium is a chemical element with the symbol Tb and atomic number 65. (wikipedia.org)
Magnetic2
- As a component of Terfenol-D (an alloy that expands and contracts when exposed to magnetic fields more than any other alloy), terbium is of use in actuators, in naval sonar systems and in sensors. (wikipedia.org)
- High magnetic field properties of gadolinium, terbium, and holmium. (nps.edu)
Lovely2
- Comment from Ethan, the source of this lovely vacuum distilled terbium: "This is crystalline distilled terbium, from ~25 years ago, before China had taken over the rare earth industry. (theodoregray.com)
- This is a lovely bumpy little rod of very pure terbium metal. (theodoregray.com)
Form2
- Terbium was not isolated in pure form until the advent of ion exchange techniques. (wikipedia.org)
- Terbium easily oxidizes, and is therefore used in its elemental form specifically for research. (wikipedia.org)
Metal3
- The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. (wikipedia.org)
- Terbium is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. (wikipedia.org)
- This unusual antiferromagnetism transforms into a disordered paramagnetic state at 230 K. Terbium metal is an electropositive element and oxidizes in the presence of most acids (such as sulfuric acid), all of the halogens, and even water. (wikipedia.org)
Typically2
- In solution, terbium typically forms trivalent species, but can be oxidized to the tetravalent state with ozone in highly basic aqueous conditions. (wikipedia.org)
- Complexes of terbium with lower coordination number are also known, typically with bulky ligands like bis(trimethyl-silylamide), which forms the three-coordinate Tb[N(SiMe3)2]3 complex. (wikipedia.org)
Temperatures1
- Terbium has a simple ferromagnetic ordering at temperatures below 219 K. Above 219 K, it turns into a helical antiferromagnetic state in which all of the atomic moments in a particular basal plane layer are parallel, and oriented at a fixed angle to the moments of adjacent layers. (wikipedia.org)
Element1
- Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite. (wikipedia.org)
Make1
- Bench-to-bedside successes: Fruitful collaborations at PSI's Center for Radiopharmaceutical Sciences make bringing Terbium-161 to the clinic a reality. (psi.ch)
