| excitatory amino acid | <biochemistry> The naturally occurring amino acids L glutamate and L aspartate and their synthetic analogues, notably kainate, quisqualate and NMDA. They have the properties of excitatory neurotransmitters in the CNS, may be involved in long-term potentiation and can act as excitotoxins. at least three classes of EAA receptor have been identified, the agonists of the N type receptor are L aspartate, NMDA and ibotenate, the agonists of the Q type receptor are L glutamate and quisqualate, agonists of the K type are L glutamate and kainate. All three receptor types are found widely in the CNS and particularly the telencephalon, N and Q type receptors tend to occur together and may interact, their distribution is complementary to the K type receptors. The ion fluxes through the Q and K receptors are relatively brief, whereas the flux through the N type is longer and carries a significant amount of calcium. Additionally the N type receptor is blockaded by magnesium near the resting potential and thus shows voltage gated ion channel properties, leading to a regenerative response, this is why N type receptors have been linked to long-term potentiation. Invertebrate glutamate receptors may not have the same properties as those described above. (18 Nov 1997) |
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| excitatory amino acid agents | Drugs used for their actions on any aspect of excitatory amino acid neurotransmitter systems. Included are drugs that act on excitatory amino acid receptors, affect the life cycle of excitatory amino acid transmitters, or affect the survival of neurons using excitatory amino acids. (12 Dec 1998) |
| excitatory amino acid agonists | Drugs that bind to and activate excitatory amino acid receptors. (12 Dec 1998) |
| excitatory amino acid antagonists | Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists. (12 Dec 1998) |
| 1-carbamoyl-L-amino acid amidohydrolase | <enzyme> From bacillus stearothermophilus; amino acid sequence given in first source Registry number: EC 3.5.1.- Synonym: carbamoyl l-aa amidohydrolase, n-carbamyl-l-amino acid amidohydrolase (26 Jun 1999) |
| amino- | <prefix> Prefix denoting a compound containing the radical, -NH2. Origin: an(monia) + in(e) + -o- (05 Mar 2000) |
| 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 acids, peptides, and proteins | Amino acids and chains of amino acids connected by peptide linkages. (12 Dec 1998) |
| 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) |
| amino group | <biochemistry> An -NH2 group. Organic compounds which have this group are called amines. (09 Oct 1997) |
| amino sugar | <biochemistry> Monosaccharide in which an OH group is replaced with an amino group, often acetylated. Common examples are D galactosamine, D glucosamine, neuraminic acid, muramic acid. Amino sugars are important constituents of bacterial cell walls, some antibiotics, blood group substances, milk oligosaccharides and chitin. (18 Nov 1997) |
| amino sugars | Sugar's in which a hydroxyl group has been replaced with an amino group; e.g., d-glucosamine. (05 Mar 2000) |