| 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) |
|---|---|
| amino acid isomerases | <enzyme> Enzymes that catalyze either the racemization or epimerization of chiral centres within amino acids or derivatives. Registry number: EC 5.1.1.- (12 Dec 1998) |
| amino acid naphthylamidases | <enzyme> Registry number: EC 3.4.11. (12 Dec 1998) |
| 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) |
| 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 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) |
| aminocaproic acid | <chemistry> A group of compounds that are derivatives of aminohexanoic acids. <haematology> An antifibrinolytic agent, used to prevent bleeding in haemophilia, and after heart and prostate surgery when plasminogen or urokinase may be activated. (05 Mar 2000) |
| aminocarboxylic 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) |
| aminocitric acid | HOOCCH(NH3+)C(COOH)(OH)CH2CO; OH;found in acid hydrolysates of ribonucleoprotein in human spleen. (05 Mar 2000) |