| alpha-keto acid dehydrogenase complex | See: alpha-keto acid dehydrogenase. Anaerobic dehydrogenase, an enzyme (usually a pyridinoenzyme) catalyzing the transfer of hydrogen from some metabolite to some acceptor molecule (e.g., NAD+, cytochrome) other than oxygen; e.g., lactate dehydrogenase's, isocitrate dehydrogenase's, and others in EC class 1, excluding those listed under aerobic dehydrogenase. (05 Mar 2000) |
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| alpha-ketoglutaramic acid | H2N-COCH2CH2COCOOH;a metabolite of glutamine formed by the action of glutamine aminotransferase; elevated in certain cases of hepatocoma. Synonym: 2-oxoglutaric acid. (05 Mar 2000) |
| alpha-ketosuccinamic acid | NH2-CO-CH2-CO-COOH;the transamination product of asparagine; acted upon by ω-amidase. (05 Mar 2000) |
| alpha-linolenic acid | <chemical> (z,z,z)-9,12,15-octadecatrienoic acid. A fatty acid that is found in plants and involved in the formation of prostaglandins. Chemical name: 9,12,15-Octadecatrienoic acid, (Z,Z,Z)- (12 Dec 1998) |
| alpha-(N-acetylaminomethylene)succinic acid hydrolase | <enzyme> Involved in degradation of vitamin b6; forms acetic acid plus ammonia plus carbon dioxide plus succinic monoaldehyde Registry number: EC 3.5.1.- Synonym: compound a hydrolase (26 Jun 1999) |
| alpha-N-acylamino acid hydrolase | <enzyme> Functions in catabolism of n-acetylamino acids resulting from turnover of alpha-n-acetylated proteins Registry number: EC 3.5.1.- Synonym: alpha-n-acetylamino acid hydrolase, anaa-hase, n-acylaminoacyl-peptide hydrolase (26 Jun 1999) |
| Altmann's anilin-acid fuchsin stain | <technique> A mixture of picric acid, anilin, and acid fuchsin which stains mitochondria crimson against a yellow background. (05 Mar 2000) |
| ametriodinic acid | <chemical> 3-acetamido-5-(acetamidomethyl)-2,4,6-triiodobenzoic acid. An ionic monomeric contrast medium. Pharmacological action: contrast media. Chemical name: Benzoic acid, 3-(acetylamino)-5-((acetylamino)methyl)-2,4,6-triiodo- (12 Dec 1998) |
| aminoacetic acid | <amino acid, physiology> The simplest amino acid. It is a common residue in proteins, especially collagen and elastin and is not optically active. It is also a major inhibitory neurotransmitter in spinal cord and brainstem of vertebrate central nervous system. (18 Nov 1997) |
| amino acid | <biochemistry> A class of organic molecules that containing an amino group and can combine in linear arrays to form proteins in living organisms. There are twenty common amino acids: alanine, arginine, aspargine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. They are key components in all living things from which proteins are synthesised by formation of peptide bonds during ribosomal translation of messenger RNA. All the amino acids have the L configuration, except glycine which is not optically active. Other amino acids occurring in proteins, such as hydroxyproline in collagen, are formed by post translational enzymatic modification of amino acid residues in polypeptide chains. There are also several important amino acids, such as the neurotransmitter y aminobutyric acid, that have no relation to proteins. Amino acids can now be produced by biotechnology in bulk using fermentation and biotransformation. Acronym: AA (13 Nov 1997) |
| amino acid activating enzyme | <enzyme> Enzymes catalyzing the formation of a specific aminoacyl-tRNA from an amino acid and adenosine 5'-triphosphate with the concomitant formation of adenosine 5'-monophosphate and pyrophosphate. Synonym: amino acid activating enzyme, aminoacyl-tRNA ligases. (05 Mar 2000) |
| amino acid activation | The first step of protein synthesis, whereby an amino acid reacts with adenosine triphosphate in the presence of aminoacyl RNA synthetase to produce an amino acid adenylate, which provides the energy necessary for the attachment of the amino acid to a specific transfer RNA molecule. (12 Dec 1998) |
| amino acid analysis | Determination and identification of amino acid content of a macromolecule, identification of a specific amino acid in macromolecules, often a mutated protein, identification and quantitation of amino acid content in blood plasma or urine; a key diagnostic aid. (05 Mar 2000) |
| amino acid chloromethyl ketones | <chemical> Inhibitors of serine proteinases and sulfhydryl group-containing enzymes. They act as alkylating agents and are known to interfere in the translation process. Pharmacological action: alkylating agents, protein synthesis inhibitor, serine proteinase inhibitors. (12 Dec 1998) |
| amino acid dehydrogenases | Enzymes catalyzing the oxidative deamination of amino acids to the corresponding oxo (keto) acids; two relatively non-specific varieties exist, l and d, for which l-amino acids and d-amino acids are the respective substrates; the products include NH3 and a reduced hydrogen acceptor (NADH in the l case); amino acid dehydrogenases of greater specificity exist, (e.g., glycine dehydrogenase). Compare: amino acid oxidases. (05 Mar 2000) |