| amino acid oxidases | Flavoenzymes oxidizing, with O2 and H20, either l-or d-amino acids specifically, to the corresponding 2-keto acids, NH3 and H2O2. Compare: amino acid dehydrogenases, yellow enzyme. (05 Mar 2000) |
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| amino acid oxidoreductases | <enzyme> A class of enzymes that catalyze oxidation-reduction reactions of amino acids. Registry number: EC 1.4. (12 Dec 1998) |
| amino acid permease | <enzyme> A widely distributed group of large Integral membrane proteins, required for the entry of amino acids into cells. (18 Nov 1997) |
| amino acid receptor | <biochemistry> Ligand gated ion channels with specific receptors for amino acid transmitters. An extended protein superfamily that also includes subunits of the nicotinic acetylcholine receptor. (18 Nov 1997) |
| amino acid sequence | The sequence of amino acids as arrayed in chains, sheets, etc., within the protein molecule. This is referred to as the primary structure of proteins. It is of fundamental importance in determining protein conformation. (12 Dec 1998) |
| amino acid substitution | The naturally occurring or experimentally induced replacement of one or more amino acids in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties. (12 Dec 1998) |
| amino acid transmitter | <biochemistry> Amino acids released as neurotransmitter substances from nerve terminals and acting on postsynaptic receptors for example _ aminobutyric acid (GABA) and glycine that are fast inhibitory transmitters in the mammalian central nervous system. Glutamate and aspartate mediate fast excitatory transmission. Strychnine (for glycine) and bicuculline for GABA) are blocking agents for amino acid action. (18 Nov 1997) |
| aromatic d-amino-acid decarboxylase | <enzyme> An enzyme that catalyses the decarboxylation of l-dopa to dopamine, of l-tryptophan to tryptamine, and of l-hydroxytryptophan to serotonin; important in the biosynthetic pathway of catecholamines and melanin. Synonym: dopa decarboxylase, hydroxytryptophan decarboxylase, tryptophan decarboxylase. (05 Mar 2000) |
| aromatic-l-amino-acid decarboxylases | <enzyme> An enzyme group with broad specificity. The enzymes decarboxylate a range of aromatic amino acids including dopa (dopa decarboxylase), tryptophan, and hydroxytryptophan. Chemical name: Aromatic-L-amino-acid carboxy-lyase Registry number: EC 4.1.1.28 (12 Dec 1998) |
| basic amino acid | An amino acid containing a second basic group (usually an amino group); e.g., lysine, arginine, ornithine. Synonym: dibasic amino acid. (05 Mar 2000) |
| receptors, amino acid | Cell surface proteins that bind amino acids and trigger changes which influence the behaviour of cells. Glutamate receptors are the most common receptors for fast excitatory synaptic transmission in the vertebrate central nervous system, and gaba and glycine receptors are the most common receptors for fast inhibition. (12 Dec 1998) |
| glucogenic amino acid | <biochemistry> A type of amino acid with carbon chains that can be broken down into an intermediate of the citric acid cycle such as glycogen and then converted into glucose as a means of entering the normal process of carbohydrate metabolism in the body. Examples include: Glycine, alanine, arginine, and ornithine. (14 Oct 1997) |
| RNA, transfer, amino acid-specific | A group of transfer rnas which are specific for carrying each one of the 20 amino acids to the ribosome in preparation for protein synthesis. (12 Dec 1998) |
| polar amino acid | An alpha-amino acid in which the functional group attached to the alpha-carbon (i.e., R in RCH(NH2)COOH) has hydrophilic properties; e.g., serine, cysteine, homocysteine. (05 Mar 2000) |
| sequence homology, amino acid | The degree of similarity between sequences of amino acids. This information is useful for the understanding of genetic relatedness of certain species. (12 Dec 1998) |