| purine | <biochemistry, molecular biology> A heterocyclic compound with a fused pyrimidine/imidazole ring. Planar and aromatic in character. The parent compound for the purine bases of nucleic acids. (18 Nov 1997) |
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| purine 5'-nucleotidase | <enzyme> Associated with some immunologic deficiency diseases Registry number: EC 3.1.3.- (26 Jun 1999) |
| purine base | A purine. (05 Mar 2000) |
| purine-free diet | A diet containing a minimal quantity of purine bases (meats); liver, kidney, and sweetbread especially are excluded and replaced by dairy products, fruits, and cereals; alcoholic beverages also are excluded. Synonym: purine-free diet. (05 Mar 2000) |
| purine imidazole-ring cyclase | <enzyme> Recyclises ring-opened purine formamidopyrimidines in irradiated DNA, restoring the c-8 to n-9 band, does not require ATP Registry number: EC 6.3.3.- Synonym: purir cyclase (26 Jun 1999) |
| purine-nucleoside phosphorylase | <enzyme> An enzyme that catalyses the reaction between a purine nucleoside and orthophosphate to form a free purine plus ribose-5-phosphate. Chemical name: Purine-nucleoside:orthophosphate ribosyltransferase Registry number: EC 2.4.2.1 (12 Dec 1998) |
| purine permease | <chemical> Enzyme in transport system of purines in yeast pichia guillermondii Chemical name: permease, purine (26 Jun 1999) |
| purine phosphoribosyltransferase | <enzyme> Specific purine phosphoribosyltransferases are EC 2.4.2.7 and 2.4.2.8. Registry number: EC 2.4.2.- (26 Jun 1999) |
| purine-restricted diet | See: gout diet. (05 Mar 2000) |
| purine ribonucleoside | A toxic nucleoside isolated from the mushroom Agaricus nebularis and from Streptomyces sp. Synonym: 9-beta-ribofuranosylpurine, purine ribonucleoside, ribosylpurine. (05 Mar 2000) |
| low purine diet | A diet low in precursors of purines (such as tissues rich in cells with abundant nuclei, as in liver, glandular meats, etc.) to minimise formation of uric acid. Useful in treatment of patients with gout or urate-containing renal calculi. (05 Mar 2000) |
| acidic amino acid | An Amino acid with a second acid moiety, e.g., glutamic acid, aspartic acid, cysteic acid. (05 Mar 2000) |
| activated amino acid | The product formed by the condensation of the acyl radical of an amino acid and adenosine 5'-monophosphate (originally in the form of adenosine 5'-triphosphate, with elimination of a pyrophosphoric group). Formed in the first step of protein biosynthesis. Synonym: activated amino acid. (05 Mar 2000) |
| alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid | <chemical> Alpha-amino-2,3-dihydro-5-methyl-3-oxo-4-isoxazolepropanoic acid. An ibotenic acid homolog and glutamate agonist. The compound is the defining agonist for the ampa subtype of glutamate receptors (receptors, ampa). It has been used as a radionuclide imaging agent but is more commonly used as an experimental tool in cell biological studies. Pharmacological action: excitatory amino acid agonists. Chemical name: 4-Isoxazolepropanoic acid, alpha-amino-2,3-dihydro-5-methyl-3-oxo- (12 Dec 1998) |
| alpha-amino acid | Typically, an amino acid of the general formula R-CHNH2-COOH (i.e., the NH2 in the a position); the l forms of these are the hydrolysis products of proteins. In rarer usages, this class of molecules also includes alpha-amino phosphoric acids and alpha-aminosulfonic acids. (05 Mar 2000) |