| amino acid neurotransmitters | Amino acids released by neurons as intercellular messengers. Among the amino acid neurotransmitters are glutamate (glutamic acid) and gaba which are, respectively, the most common excitatory and inhibitory neurotransmitters in the central nervous system. (12 Dec 1998) |
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| 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) |
| 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 reagent | A reagent used in the identification and quantification of amino acids. (05 Mar 2000) |
| 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 acids | Organic compounds that generally contain an amino (-nh2) and a carboxyl (-cooh) group. Twenty alpha-amino acids are the subunits which are polymerised to form proteins. (12 Dec 1998) |
| amino acids, branched-chain | Amino acids which have a branched carbon chain. (12 Dec 1998) |
| amino acids, cyclic | A class of amino acids characterised by a closed ring structure. (12 Dec 1998) |
| 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 acids, peptides, and proteins | Amino acids and chains of amino acids connected by peptide linkages. (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) |
| amino acyl-tRNA ligases | <enzyme> Any of the group of ligases that catalyses the ATP-driven formation of a bond between an amino acid and a trna, activating the amino acids as a step in protein synthesis. Individual enzymes are highly specific for one amino acid and for any trna corresponding to that amino acid. Registry number: EC 6.1.1. (12 Dec 1998) |
| amino alcohols | Compounds possessing both a hydroxyl (-oh) and an amino group (-nh2). (12 Dec 1998) |