| 3-hydroxy-3-methylglutaryl-CoA | -OOCCH2C(OH)(CH3)CH2COS-CoA;a key intermediate in the synthesis of ketone bodies and of steroids. Synonym: 3-hydroxy-3-methylglutaryl-CoA. Beta-hydroxy-beta-methylglutaryl-lyase, an enzyme, found primarily in liver and rumen epithelium that catalyses the formation of acetyl-CoA and acetoacetate from beta-hydroxy-beta-methylglutaryl-CoA; a key step in ketogenesis; a deficiency of this enzyme leads to episodes of severe metabolic acidosis without ketosis. Beta-hydroxy-beta-methylglutaryl-reductase, an enzyme that catalyses the rate-limiting step of cholesterol biosynthesis, beta-hydroxy-beta-methylglutaryl-CoA + 2NADPH + 2H+ → mevalonate + 2NADP+ + coenzyme A. Beta-hydroxy-beta-methylglutaryl-synthase, an enzyme in mitochondria that catalyses the reaction of acetyl-CoA with acetoacetyl-CoA and water to form beta-hydroxy-beta-methylglutaryl-CoA and coenzyme A, a step required for both ketogenesis and steroidogenesis to occur. (05 Mar 2000) |
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| 3-hydroxy-4-oxoquinoline oxygenase | <enzyme> Forms n-formylanthranilic acid + co2; 24 amino acids of n-terminal sequence given in first source Registry number: EC 1.13.12.- Synonym: 1h-3-hydroxy-4-oxoquinoline oxygenase, 3-oh-4-oxoquinoline oxygenase (26 Jun 1999) |
| 4-(4'-hydroxy-3'-methylbut-2'-enyl)-L-tryptophan synthetase | <enzyme> Enzymatic synthesis of above cpd from isopentenylpyrophosphate and tryptophan Registry number: EC 6.- (26 Jun 1999) |
| 4-hydroxy-2-ketopimelate aldolase | <enzyme> Bacterial enzyme functioning in pathways of aromatic catabolism; forms pyruvate and succinic saemialdehyde Registry number: EC 4.1.3.- (26 Jun 1999) |
| 4-hydroxy-2-ketovalerate aldolase | <enzyme> Forms acetaldehyde + pyruvate; catalyses conversion of 4-hydroxy-2-ketovalerate to pyruvate Registry number: EC 4.1.3.- (26 Jun 1999) |
| 4-hydroxy-2-oxovalerate aldolase | <enzyme> Forms pyruvate + acetaldehyde; enzyme g of p-cumate catabolic pathway in pseudomonas putida Registry number: EC 4.1.3.- Synonym: nahm gene product, cmtg gene product (26 Jun 1999) |
| 4-hydroxy-5-polyprenylbenzoate hydroxylase | <enzyme> Involved in ubiquinone biosynthesis Registry number: EC 1.14.13.- Synonym: 4-oh-5-ppb hydroxylase (26 Jun 1999) |
| 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylic acid dehydrogenase | <enzyme> Nad+ dependent; from pseudomonas ma-1 grown on pyridoxine; involved in vitamin b6 degradation Registry number: EC 1.1.1.- Synonym: fhmpc dehydrogenase (26 Jun 1999) |
| 5-hydroxy-N-methylpyroglutamic acid synthetase | <enzyme> Methylamine plus alpha-ketoglutarate gives 5-hydroxy-n-methylpyroglutamic acid Registry number: EC 4.2.1.- (26 Jun 1999) |
| 5-hydroxy tryptamine antagonists | Agents which block serotonin receptors and hence interfere with the biological actions of serotonin (5-HT). (05 Mar 2000) |
| 8-hydroxy-2-(di-n-propylamino)tetralin | <chemical> 7-(dipropylamino)-5,6,7,8-tetrahydro-1-naphthalenol. A serotonin 1a-receptor agonist that is being used experimentally to test the effects of serotonin. Pharmacological action: serotonin agonists. Chemical name: 1-Naphthalenol, 7-(dipropylamino)-5,6,7,8-tetrahydro- (12 Dec 1998) |
| 8-hydroxy-5-deazaflavin-dependent DNA photolyase | <enzyme> From anacystis nidulans; purified in streptomyces coelicolor; distinguish from folate-dependent DNA photolyase Registry number: EC 4.1.99.- Synonym: 8-hdfd-DNA photolyase (26 Jun 1999) |
| 8-hydroxy-5-deazaflavin-NADPH oxidoreductase | <enzyme> From streptomyces griseus; mw 42kda; acts as an electron transfer carrier Registry number: EC 1.6.99.- Synonym: hdaf-NADPH oxidoreductase (26 Jun 1999) |
| acids, carbocyclic | Carboxylic acids that have a homocyclic ring structure in which all the ring atoms are carbon. (12 Dec 1998) |
| acids, heterocyclic | A class of acids containing a ring structure in which atleast one atom other than carbon is incorporated. (12 Dec 1998) |