Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.Tryptophan Oxygenase: A dioxygenase with specificity for the oxidation of the indoleamine ring of TRYPTOPHAN. It is a LIVER-specific enzyme that is the first and rate limiting enzyme in the kynurenine pathway of TRYPTOPHAN catabolism.Tryptophan Synthase: An enzyme that catalyzes the conversion of L-serine and 1-(indol-3-yl)glycerol 3-phosphate to L-tryptophan and glyceraldehyde 3-phosphate. It is a pyridoxal phosphate protein that also catalyzes the conversion of serine and indole into tryptophan and water and of indoleglycerol phosphate into indole and glyceraldehyde phosphate. (From Enzyme Nomenclature, 1992) EC 4.2.1.20.Tryptophan Hydroxylase: An enzyme that catalyzes the hydroxylation of TRYPTOPHAN to 5-HYDROXYTRYPTOPHAN in the presence of NADPH and molecular oxygen. It is important in the biosynthesis of SEROTONIN.KynurenineBromosuccinimide: A brominating agent that replaces hydrogen atoms in benzylic or allylic positions. It is used in the oxidation of secondary alcohols to ketones and in controlled low-energy brominations. (From Miall's Dictionary of Chemistry, 5th ed; Hawley's Condensed Chemical Dictionary, 12th ed,).Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Indoleamine-Pyrrole 2,3,-Dioxygenase: A dioxygenase with specificity for the oxidation of the indoleamine ring of TRYPTOPHAN. It is an extrahepatic enzyme that plays a role in metabolism as the first and rate limiting enzyme in the kynurenine pathway of TRYPTOPHAN catabolism.Anthranilate Synthase: An enzyme that catalyzes the formation of anthranilate (o-aminobenzoate) and pyruvic acid from chorismate and glutamine. Anthranilate is the biosynthetic precursor of tryptophan and numerous secondary metabolites, including inducible plant defense compounds. EC 4.1.3.27.ortho-Aminobenzoates: Benzoic acids, salts, or esters that contain an amino group attached to carbon number 2 or 6 of the benzene ring structure.Acrylamide: A colorless, odorless, highly water soluble vinyl monomer formed from the hydration of acrylonitrile. It is primarily used in research laboratories for electrophoresis, chromatography, and electron microscopy and in the sewage and wastewater treatment industries.XanthurenatesAmino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Serotonin: A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Hydroxyindoleacetic AcidTryptophanase: An enzyme that catalyzes the conversion of L-tryptophan and water to indole, pyruvate, and ammonia. It is a pyridoxal-phosphate protein, requiring K+. It also catalyzes 2,3-elimination and beta-replacement reactions of some indole-substituted tryptophan analogs of L-cysteine, L-serine, and other 3-substituted amino acids. (From Enzyme Nomenclature, 1992) EC 4.1.99.1.3-Hydroxyanthranilic Acid: An oxidation product of tryptophan metabolism. It may be a free radical scavenger and a carcinogen.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Kinetics: The rate dynamics in chemical or physical systems.Phenylalanine: An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Anthranilate Phosphoribosyltransferase: An enzyme that catalyzes the formation of N-5'-phosphoribosylanthranilic acid from anthranilate and phosphoribosylpyrophosphate, the first step in tryptophan synthesis in E. coli. It exists in a complex with ANTHRANILATE SYNTHASE in bacteria. EC 2.4.2.18.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Fluorescence: The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.Tryptophan-tRNA Ligase: An enzyme that activates tryptophan with its specific transfer RNA. EC 6.1.1.2.Indoles: Benzopyrroles with the nitrogen at the number one carbon adjacent to the benzyl portion, in contrast to ISOINDOLES which have the nitrogen away from the six-membered ring.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Kynurenine 3-Monooxygenase: An NADPH-dependent flavin monooxygenase that plays a key role in the catabolism of TRYPTOPHAN by catalyzing the HYDROXYLATION of KYNURENINE to 3-hydroxykynurenine. It was formerly characterized as EC 1.14.1.2 and EC 1.99.1.5.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Fluorescence Polarization: Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.Quinolinic Acid: A metabolite of tryptophan with a possible role in neurodegenerative disorders. Elevated CSF levels of quinolinic acid are correlated with the severity of neuropsychological deficits in patients who have AIDS.Indole-3-Glycerol-Phosphate Synthase: An enzyme in the tryptophan biosynthetic pathway. EC 4.1.1.48.Niacin: A water-soluble vitamin of the B complex occurring in various animal and plant tissues. It is required by the body for the formation of coenzymes NAD and NADP. It has PELLAGRA-curative, vasodilating, and antilipemic properties.5-Hydroxytryptophan: The immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant.Indolequinones: INDOLES which have two keto groups forming QUINONES like structures of the indole aromatic ring.Acrylamides: Colorless, odorless crystals that are used extensively in research laboratories for the preparation of polyacrylamide gels for electrophoresis and in organic synthesis, and polymerization. Some of its polymers are used in sewage and wastewater treatment, permanent press fabrics, and as soil conditioning agents.Quinolinic AcidsOperon: In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.RNA, Transfer, Trp: A transfer RNA which is specific for carrying tryptophan to sites on the ribosomes in preparation for protein synthesis.Energy Transfer: The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.SkatoleTyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.Protein Structure, Secondary: The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.Pellagra: A disease due to deficiency of NIACIN, a B-complex vitamin, or its precursor TRYPTOPHAN. It is characterized by scaly DERMATITIS which is often associated with DIARRHEA and DEMENTIA (the three D's).Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Transaminases: A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.Glycerophosphates: Any salt or ester of glycerophosphoric acid.Enzyme Repression: The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.Kynurenic Acid: A broad-spectrum excitatory amino acid antagonist used as a research tool.Bacterial Proteins: Proteins found in any species of bacterium.Amino Acid Transport Systems: Cellular proteins and protein complexes that transport amino acids across biological membranes.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Histidine: An essential amino acid that is required for the production of HISTAMINE.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Guanidine: A strong organic base existing primarily as guanidium ions at physiological pH. It is found in the urine as a normal product of protein metabolism. It is also used in laboratory research as a protein denaturant. (From Martindale, the Extra Pharmacopoeia, 30th ed and Merck Index, 12th ed) It is also used in the treatment of myasthenia and as a fluorescent probe in HPLC.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Apoproteins: The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).Anilino Naphthalenesulfonates: A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.

Enrichment of enzyme activity on deformylation of 1-NFK-lysozyme. (1/5574)

The formamide linkage of an inactive lysozyme derivative (1-NFK-lysozyme), formed by selective ozonization of tryptophan 62 in hen egg-white lysozyme [EC 3.2.1.17] was hydrolyzed with dilute acid faster in the frozen state at about --10 degrees than at 20 degrees. On hydrolysis of 1-NFK-lysozyme the low lytic activity increased to approximately 80% of that of native lysozyme. It is suggested that the binding ability associated with kynurenine 62 in the lysozyme derivative formed by this hydrolysis may be responsible for increase in enzymatic activity.  (+info)

Folding of apocytochrome c induced by the interaction with negatively charged lipid micelles proceeds via a collapsed intermediate state. (2/5574)

Unfolded apocytochrome c acquires an alpha-helical conformation upon interaction with lipid. Folding kinetic results below and above the lipid's CMC, together with energy transfer measurements of lipid bound states, and salt-induced compact states in solution, show that the folding transition of apocytochrome c from the unfolded state in solution to a lipid-inserted helical conformation proceeds via a collapsed intermediate state (I(C)). This initial compact state is driven by a hydrophobic collapse of the polypeptide chain in the absence of the heme group and may represent a heme-free analogue of an early compact intermediate detected on the folding pathway of cytochrome c in solution. Insertion into the lipid phase occurs via an unfolding step of I(C) through a more extended state associated with the membrane surface (I(S)). While I(C) appears to be as compact as salt-induced compact states in solution with substantial alpha-helix content, the final lipid-inserted state (Hmic) is as compact as the unfolded state in solution at pH 5 and has an alpha-helix content which resembles that of native cytochrome c.  (+info)

Pathways of electron transfer in Escherichia coli DNA photolyase: Trp306 to FADH. (3/5574)

We describe the results of a series of theoretical calculations of electron transfer pathways between Trp306 and *FADH. in the Escherichia coli DNA photolyase molecule, using the method of interatomic tunneling currents. It is found that there are two conformationally orthogonal tryptophans, Trp359 and Trp382, between donor and acceptor that play a crucial role in the pathways of the electron transfer process. The pathways depend vitally on the aromaticity of tryptophans and the flavin molecule. The results of this calculation suggest that the major pathway of the electron transfer is due to a set of overlapping orthogonal pi-rings, which starts from the donor Trp306, runs through Trp359 and Trp382, and finally reaches the flavin group of the acceptor complex, FADH.  (+info)

Localization and environment of tryptophans in soluble and membrane-bound states of a pore-forming toxin from Staphylococcus aureus. (4/5574)

The location and environment of tryptophans in the soluble and membrane-bound forms of Staphylococcus aureus alpha-toxin were monitored using intrinsic tryptophan fluorescence. Fluorescence quenching of the toxin monomer in solution indicated varying degrees of tryptophan burial within the protein interior. N-Bromosuccinimide readily abolished 80% of the fluorescence in solution. The residual fluorescence of the modified toxin showed a blue-shifted emission maximum, a longer fluorescence lifetime as compared to the unmodified and membrane-bound alpha-toxin, and a 5- to 6-nm red edge excitation shift, all indicating a restricted tryptophan environment and deeply buried tryptophans. In the membrane-bound form, the fluorescence of alpha-toxin was quenched by iodide, indicating a conformational change leading to exposure of some tryptophans. A shorter average lifetime of tryptophans in the membrane-bound alpha-toxin as compared to the native toxin supported the conclusions based on iodide quenching of the membrane-bound toxin. Fluorescence quenching of membrane-bound alpha-toxin using brominated and spin-labeled fatty acids showed no quenching of fluorescence using brominated lipids. However, significant quenching was observed using 5- and 12-doxyl stearic acids. An average depth calculation using the parallax method indicated that the doxyl-quenchable tryptophans are located at an average depth of 10 A from the center of the bilayer close to the membrane interface. This was found to be in striking agreement with the recently described structure of the membrane-bound form of alpha-toxin.  (+info)

A novel epitope for the specific detection of exogenous prion proteins in transgenic mice and transfected murine cell lines. (5/5574)

Prion diseases are closely linked to the conversion of host-encoded cellular prion protein (PrPC) into its pathological isoform (PrPSc). PrP conversion experiments in scrapie infected tissue culture cells, transgenic mice, and cell-free systems usually require unique epitopes and corresponding monoclonal antibodies (MAbs) for the immunological discrimination of exogenously introduced and endogenous PrP compounds (e.g., MAb 3F4, which is directed to an epitope on hamster and human but not on murine PrP). In the current work, we characterize a novel MAb designated L42 that reacts to PrP of a variety of species, including cattle, sheep, goat, dog, human, cat, mink, rabbit, and guinea pig, but does not bind to mouse, hamster, and rat PrP. Therefore, MAb L42 may allow future in vitro conversion and transgenic studies on PrPs of the former species. The MAb L42 epitope on PrPC includes a tyrosine residue at position 144, whereas mouse, rat, and hamster PrPs incorporate tryptophane at this site. To verify this observation, we generated PrP expression vectors coding for authentic or mutated murine PrPCs (i.e., codon 144 encoding tyrosine instead of tryptophan). After transfection into neuroblastoma cells, MAb L42 did not react with immunoblotted wild-type murine PrPC, whereas L42 epitope-tagged murine PrPC was strongly recognized. Immunoblot and fluorescence-activated cell sorting data revealed that tagged PrPC was correctly posttranslationally processed and translocated to the cell surface.  (+info)

Helical structure and packing orientation of the S2 segment in the Shaker K+ channel. (6/5574)

Six transmembrane segments, S1-S6, cluster around the central pore-forming region in voltage-gated K+ channels. To investigate the structural characteristics of the S2 segment in the Shaker K+ channel, we replaced each residue in S2 singly with tryptophan (or with alanine for the native tryptophan). All but one of the 23 Trp mutants expressed voltage-dependent K+ currents in Xenopus oocytes. The effects of the mutations were classified as being of low or high impact on channel gating properties. The periodicity evident in the effects of these mutations supports an alpha-helical structure for the S2 segment. The high- and low-impact residues cluster onto opposite faces of a helical wheel projection of the S2 segment. The low-impact face is also tolerant of single mutations to asparagine. All results are consistent with the idea that the low-impact face projects toward membrane lipids and that changes in S2 packing occur upon channel opening. We conclude that the S2 segment is a transmembrane alpha helix and that the high-impact face packs against other transmembrane segments in the functional channel.  (+info)

A single hydrophobic residue confers barbiturate sensitivity to gamma-aminobutyric acid type C receptor. (7/5574)

Barbiturate sensitivity was imparted to the human rho1 homooligomeric gamma-aminobutyric acid (GABA) receptor channel by mutation of a tryptophan residue at position 328 (Trp328), which is located within the third transmembrane domain. Substitutions of Trp328 with a spectrum of amino acids revealed that nearly all hydrophobic residues produced receptor channels that were both directly activated and modulated by pentobarbital with similar sensitivities. Previous studies with ligand-gated ion channels (including GABA) have demonstrated that even conservative amino acid substitution within the agonist-dependent activation domain (N-terminal extracellular domain) can markedly impair agonist sensitivity. Thus, the lack of significant variation in pentobarbital sensitivity among the Trp328 mutants attests to an intrinsic difference between pentobarbital- and the GABA-dependent activation domain. Compared with the heterooligomeric alphabetagamma receptor channel, the mode of modulation for homooligomeric Trp328 mutants by pentobarbital was more dependent on the GABA concentration, yielding potentiation only at low concentrations of GABA (fractions of their respective EC50 values), yet causing inhibition at higher concentrations. Agonist-related studies have also demonstrated that residue 328 plays an important role in agonist-dependent activation, suggesting a functional interconnection between the GABA and pentobarbital activation domains.  (+info)

Inhibition of myosin ATPase by metal fluoride complexes. (8/5574)

Magnesium (Mg2+) is the physiological divalent cation stabilizing nucleotide or nucleotide analog in the active site of myosin subfragment 1 (S1). In the presence of fluoride, Mg2+ and MgADP form a complex that traps the active site of S1 and inhibits myosin ATPase. The ATPase inactivation rate of the magnesium trapped S1 is comparable but smaller than the other known gamma-phosphate analogs at 1.2 M-1 s-1 with 1 mM MgCl2. The observed molar ratio of Mg/S1 in this complex of 1.58 suggests that magnesium occupies the gamma-phosphate position in the ATP binding site of S1 (S1-MgADP-MgFx). The stability of S1-MgADP-MgFx at 4 degrees C was studied by EDTA chase experiments but decomposition was not observed. However, removal of excess fluoride causes full recovery of the K+-EDTA ATPase activity indicating that free fluoride is necessary for maintaining a stable trap and suggesting that the magnesium fluoride complex is bonded to the bridging oxygen of beta-phosphate more loosely than the other known phosphate analogs. The structure of S1 in S1-MgADP-MgFx was studied with near ultraviolet circular dichroism, total tryptophan fluorescence, and tryptophan residue 510 quenching measurements. These data suggest that S1-MgADP-MgFx resembles the M**.ADP.Pi steady-state intermediate of myosin ATPase. Gallium fluoride was found to compete with MgFx for the gamma-phosphate site in S1-MgADP-MgFx. The ionic radius and coordination geometry of magnesium, gallium and other known gamma-phosphate analogs were compared and identified as important in determining which myosin ATPase intermediate the analog mimics.  (+info)

  • The assay relies on the ability to quench the intrinsic fluorescence of tryptophan residues within a protein that results from changes in the local environment polarity experienced by the tryptophan(s) upon the addition of a binding partner or ligand. (bio-protocol.org)
  • Tryptophan can be selectively excited at 295 nm as there is little absorption by other residues at this wavelength. (bio-protocol.org)
  • Structural changes in the vicinity of tryptophan residues induced by ligand/partner interactions, protein conformational changes, self-association or protein folding/denaturation, can alter the intensity of fluorescence as well as introduce a wavelength shift in the emission spectrum (Möller and Denicola, 2002). (bio-protocol.org)
  • In our body 60mg of tryptophan gives rise to 1 mg of niacin which is a member of vitamin B complex and is essential for the metabolism of carbohydrates, proteins, and fats as well as in normal functioning of the skin, intestine, and nervous system. (dailyhealthmagazine.com)
  • The overall goal of our research, as outlined in this renewal grant application, is to improve diagnosis and treatment of human brain tumors by exploiting mechanisms related to tumoral abnormalities of tryptophan metabolism. (grantome.com)
  • In Aim 3 we will study mechanisms of tryptophan metabolism in tumor samples obtained from gliomas and common metastatic brain tumors. (grantome.com)
  • The expected results will lead to novel treatment approaches targeting tumoral tryptophan-to-kynurenine metabolism (that could be blocked by specific enzyme inhibitors) and/or modulating AHR-mediated transcription. (grantome.com)
  • In this project, we combine multi-modal imaging (PET and MRI) with tumor tissue assays to exploit processes related to abnormal tumoral tryptophan metabolism in order to address the above issues in primary brain tumors and brain metastases. (grantome.com)
  • 1982). Tryptophan side effects only appeared in those rodents that had received a bypass treatment in their liver, which deranged their tryptophan metabolism. (supplements-and-health.com)
  • However, a similar, albeit short-term, study demonstrated that a comparable dose of L-tryptophan caused liver damage in animals whose metabolism of tryptophan had not been tampered with (Trulson & Sampson, 1986). (supplements-and-health.com)
  • abstract = "The photofragmentation of protonated tryptophan has been investigated in a unique experimental setup, in which ion and neutral issued from the photofragmentation are detected in coincidence, in time and in position. (elsevier.com)
  • This process is actively blocked by the fetal tissues by producing enzymes which rapidly uses up tryptophan. (rainbow.coop)
  • Kynurenine can be produced by two key enzymes (indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase) and is a recently recognized endogenous ligand for the aryl hyrocarbon receptor (AHR), an important cell-cycle regulator whose activation plays a role in both tumor progression and immune suppression. (grantome.com)
  • Liver enzymes form highly mutagenic L-tryptophan degradation products (e.g., 3-amino-1-methyl-5H-pyrido[4,3-b]indole) that cause damage to the liver, including cancer (Nemoto, et al. (supplements-and-health.com)
  • Several studies demonstrate that the consumption of tryptophan elevates the levels of serotonin , it favours relaxation , the feeling of well-being, and the mood . (hsnstore.com)
  • One of the major tryptophan benefits is the mood-lifting effect induced by an increase of serotonin - a neurotransmitter- that promotes a feeling of happiness. (vitaminexpress.org)
  • A tryptophan deficiency can cause major mood changes. (vitaminexpress.org)
  • Tryptophan capsules will boost the levels of serotonin within the human body and this will eventually result in happier and mood-lifting feelings: the more serotonin your body absorbs, the more contented you will be. (vitaminexpress.org)
  • By taking a tryptophan supplement you can regulate what your body cannot produce on its own and help lessen the symptoms of depression by improving your mood. (vitaminexpress.org)
  • Tryptophan capsules will help you achieve the level of tryptophan needed to fend off depression and mood-swings that are due to a lack of this amino acid. (vitaminexpress.org)
  • What is L-Tryptophan and How Does it Help the Brain, Mood, and Sleep? (vitanetonline.com)
  • Could tryptophan improve your chances of attaining a better mood, stronger cognitive function and better-quality sleep? (zenbev.com)
  • Tryptophan can help to improve your quality of sleep, encourage a more positive mood, and help to reduce your feelings of stress and worry without the drowsy feeling you can get with prescriptions. (simplynutrition.com)
  • Studies have shown that tryptophan can help to: Improve your quality of sleep, encourage a more positive mood, and help to reduce your feelings of stress and worry. (simplynutrition.com)
  • Tryptophan or L-tryptophan is an essential amino acid that favors a good mood and helps the body to produce certain hormones in a natural way. (hsnstore.eu)
  • When we take tryptophan, the organism transforms it into serotonin, which is the neurotransmitter in charge of controlling the mood. (hsnstore.eu)
  • A lack or deficiency of l-tryptophan can lead to endless, sleepless nights. (vitaminexpress.org)
  • Tryptophan gets converted to nicotinamide, and gets hampered in case there is vitamin B6 deficiency. (moxietoday.com)
  • For more detailed data on the alleged effectiveness of supplemental tryptophan for so-called "serotonin deficiency symptoms", such as depression and sleep disturbances, refer to my piece "Tryptophan For Sleep: One Of The Good Natural Sleeping Aids? (supplements-and-health.com)
  • A long-term animal study, using a relatively modest dose of L-tryptophan (roughly the human equivalent of 1.5-3 g per day, which is a common supplemental dose), didn't lead to tryptophan side effects such as morphological changes to the liver in healthy animals (Bucci, et al. (supplements-and-health.com)
  • Other studies on animals, however, raised more pragmatic concerns about tryptophan and liver function. (supplements-and-health.com)
  • Tryptophan from Prisma Natural has elements that act by causing the person to decrease the anxiety that can be caused by the daily routine. (masmusculo.com)
  • L-tryptophan is an amino acid which we use to form serotonin, the neurotransmitter that makes us calm and relaxed, and which is responsible for regulating our moods, anger, stress, anxiety, appetite, libido and body temperature, among many other processes. (anamarialajusticiausa.com)
  • It can also be taken at exam time to help with lack of concentration and in slimming diets, because tryptophan with magnesium + vitamin B6 considerably reduces anxiety and therefore the urge to snack. (anamarialajusticiausa.com)
  • 5), probable antenatal depression (EPDS ≥ 15) and probable anxiety (STAI-state ≥ 41) were calculated adjusting for covariates.RESULTS: Mean plasma tryptophan concentrations was 48.0µmol/L (SD: 8.09). (mcgill.ca)
  • No associations were observed between tryptophan concentrations during pregnancy and postnatal sleep quality or mental well-being.LIMITATION: Subjective measures were used to assess sleep and mental well-being.CONCLUSIONS: We observed that higher plasma tryptophan concentrations were associated with a 12% lower prevalence of poor sleep quality during pregnancy, in particular among those with anxiety symptoms. (mcgill.ca)
  • The addition of tryptophan to a stationary phase BW25113 culture leads to further indole synthesis.Stationary phase (24 hours) BW25113 cells were incubated with no additional tryptophan or 2 mM tryptophan added every subsequent 24 hours (arrows indicate times of addition). (nih.gov)
  • Memory, in particular, is a function of the brain that has shown notable improvement with the consumption of tryptophan. (zenbev.com)
  • Another facet of mental health, emotional wellbeing, is also believed to be improved by increased consumption of tryptophan-heavy foods. (zenbev.com)
  • You may find that tryptophan capsules are all you need to regulate your night sleeping habits and give you the restful sleep you have been missing. (vitaminexpress.org)
  • Moreover, tryptophan also provides a restful and healthy sleep. (hsnstore.eu)
  • There are many health benefits connected with the intake of tryptophan, otherwise known as L-Tryptophan. (vitaminexpress.org)
  • Studies have shown that the intake of tryptophan benefits anyone suffering from sleep disorders. (vitaminexpress.org)
  • Not only does Life Extension® Optimized Tryptophan Plus give your body the optimal intake of tryptophan itself, but it will also give you a balanced supply of other nutrients found to help maintain tryptophan activity in the body. (simplynutrition.com)
  • The result of Trial 1 showed that the feed intake, performance, and carcass characteristics were not influenced by tryptophan content in the diet which between 0.198% and 0.258% (p>0.05). (ajas.info)
  • Below are the list of possible Tryptophan-rich sensory protein products. (mybiosource.com)
  • Also known as Tryptophan-rich sensory protein (TSPO) (Translocator protein TspO) (TspO regulatory protein). (mybiosource.com)
  • By using single tryptophan protein phosphorescence, we follow site-specific internal protein dynamics over a broad temperature range and demonstrate three independent dynamic processes. (elsevier.com)
  • L-Tryptophan is a natural anti-depressant, plentiful in protein foods but largely lost through cooking and processing. (health-mall.in)
  • Plants and microorganisms commonly synthesize tryptophan from shikimic acid or anthranilate. (health-mall.in)
  • Subsequent bioinformatic and biological analyses reveal that yeast unable to synthesize tryptophan are especially sensitive to the presence of SDS. (jofsr.org)
  • Fingerprint Dive into the research topics of 'Comprehensive characterization of the photodissociation pathways of protonated tryptophan. (elsevier.com)
  • Culture of splenic T cells or purified CD8 + T cells with IDO + DCs, or with LT and kynurenines, results in selective CD3ζ down-regulation that is concomitant with tryptophan consumption and kynurenine production and is mediated by GCN2. (jimmunol.org)
  • Very high doses of L-tryptophan, over 10g -or even 30g- per day, had been used by some people during the 1980s as the tryptophan tragedy of 1989 had uncovered (Crist, 2005). (supplements-and-health.com)
  • Comprehensive characterization of the photodissociation pathways of protonated tryptophan. (elsevier.com)
  • 2020. https://nursing.unboundmedicine.com/nursingcentral/view/Davis-Drug-Guide/110127/all/L_tryptophan. (unboundmedicine.com)
  • Tryptophan is the nutritional social worker in our body who helps everyone else but risks getting worn out and depleted in the process. (zenbev.com)
  • Life Extension® Optimized Tryptophan Plus contains premium L-tryptophan which has undergone significantly more rigorous manufacturing processes than regular tryptophan material, to assure the highest purity and safety. (simplynutrition.com)