| hydroxylase | <enzyme> A type of enzyme which adds -OH groups to its substrate during hydroxylation reactions by attaching oxygen atoms to it. (09 Oct 1997) |
|---|---|
| hydroxylases | <enzyme> Registry number: EC 1.14. (12 Dec 1998) |
| hydroxylation | Hydroxylate, to introduce hydroxyl into (a compound or radical) usually by replacement of hydrogen. (18 Nov 1997) |
| hydroxylysine | Post translationally hydroxylated lysine is found in collagen and commonly has galactose and then glucose added sequentially by glycosyl transferases. The extent of glycosylation varies with the collagen type. (18 Nov 1997) |
| hydroxymandelonitrile lyase | <enzyme> Catalyses the reversible condensation of cyanide with 4-hydroxybenzaldehyde to yield 4-hydroxymandelonitrile; can be obtained from plant extracts by immobilised metal ion affinity chromatography Registry number: EC 4.1.2.11 Synonym: hmn lyase, 4-hydroxymandelonitrile hydroxybenzaldehyde-lyase, hydroxynitrile lyase (26 Jun 1999) |
| hydroxymercuribenzoates | <chemical> Hydrxylated benzoic acid derivatives that contain mercury. Some of these are used as sulfhydryl reagents in biochemical studies. Pharmacological action: enzyme inhibitors, sulfhydryl reagents. (12 Dec 1998) |
| hydroxymethyl and formyl transferases | <enzyme> Enzymes that catalyze the transfer of hydroxymethyl or formyl groups. Registry number: EC 2.1.2 (12 Dec 1998) |
| hydroxymethylbilane synthase | <enzyme> An enzyme that catalyses the formation of hydroxymethylbilane from four molecules of porphobilinogen. Chemical name: Porphobilinogen ammonia-lyase (polymerizing) Registry number: EC 4.3.1.8 (12 Dec 1998) |
| hydroxymethyldeoxyuridinemonophosphate kinase | <enzyme> An aspect of nucleoside monophosphate kinase EC 2.7.4.4 Registry number: EC 2.7.4.- Synonym: hmdump kinase, hydroxymethyldeoxyuridine monophosphate kinase (26 Jun 1999) |
| hydroxymethyldihydropterin pyrophosphokinase | <enzyme> Convets 6-hydroxymethyl-7,8-dihydropterin and ATP to 6-hydroxymethyl-7,8-dihydropterin pyrophosphate and AMP Registry number: EC 2.7.6.- Synonym: suld gene product (26 Jun 1999) |
| hydroxymethylglutaryl CoA reductases | <enzyme> In the biosynthesis of cholesterol, these enzymes catalyze the reduction of one of the carboxyl groups of beta-hydroxy, beta-methylglutaryl CoA to yield mevalonic acid.4 requires NADP, EC 1.1.1.88 requires NAD. Chemical name: (S)-Mevalonate:NAD+ oxidoreductase (CoA-acylating) Registry number: EC 1.1.1.88 (12 Dec 1998) |
| hydroxymethylglutaryl-CoA reductase inhibitors | Compounds that inhibit hmg-CoA reductases. They have been shown to directly lower cholesterol synthesis. (12 Dec 1998) |
| hydroxymethylglutaryl-CoA synthase | <enzyme> An enzyme that catalyses the synthesis of hydroxymethylglutaryl-CoA from acetyl-CoA and acetoacetyl-CoA. This is a key enzyme in steroid biosynthesis. Chemical name: (S)-3-Hydroxy-3-methylglutaryl-CoA acetoacetyl-CoA-lyase (CoA-acetylating) Registry number: EC 4.1.3.5 (12 Dec 1998) |
| hydroxymethylgutaryl-CoA hydrolase | <enzyme> May be important in regulating mammalian cholesterol synthesis Registry number: EC 3.1.2.5 Synonym: beta-hydroxy-beta-methylglutaryl coenzyme a hydrolase, beta-hydroxy-beta-methylglutaryl coenzyme a deacylase (26 Jun 1999) |
| hydroxymethylpyrimidine kinase | <enzyme> Found in E coli; catalyses th phosphorylation of 4-amino-5-hydroxymethyl-2-methylpyrimidine to 4-amino-5-phosphomethyl-2-methylpyrimidine in the presence of ATP Registry number: EC 2.7.1.49 (26 Jun 1999) |