| 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) |
|---|---|
| 3-hydroxyacyl-CoA dehydrogenase | Beta-Hydroxyacyl dehydrogenase;enzyme catalyzing the oxidation of an l-3-hydroxyacyl-CoA to a 3-ketoacyl-CoA with reduction of NAD+; one of the enzymes of the b oxidation of fatty acids. Synonym: beta-ketohydrogenase, beta-ketoreductase. (05 Mar 2000) |
| 3-hydroxyacyl CoA dehydrogenases | <enzyme> Enzymes that reversibly catalyze the oxidation of a 3-hydroxyacyl CoA to 3-ketoacyl CoA in the presence of NAD. They are key enzymes in the oxidation of fatty acids and in mitochondrial fatty acid synthesis. Chemical name: (S)-3-Hydroxyacyl-CoA:NAD+ oxidoreductase Registry number: EC 1.1.1.35 (12 Dec 1998) |
| 3-ketoacid-CoA transferase | <enzyme> An enzyme catalyzing the reversible conversion of acetoacetyl-CoA and succinate into succinyl-CoA and acetoacetate; malonyl-CoA can substitute for succinyl-CoA and a few other 3-oxo acids for the acetoacetate; an important step in order for the ketone bodies to serve as a fuel for extrahepatic tissues. Synonym: 3-ketoacid-CoA transferase, acetoacetyl-succinic thiophorase. (05 Mar 2000) |
| 3-ketoacyl-CoA thiolase | <enzyme> An enzyme catalyzing the thioclastic cleavage by coenzyme A of beta-ketoacyl-CoA, forming an acyl-CoA with a carbon chain shorter by two atoms, the missing two atoms appearing as acetyl-CoA. A step in fatty acid degradation. See: acetyl-CoA acetyltransferase. Synonym: 3-ketoacyl-CoA thiolase, beta-ketothiolase. (05 Mar 2000) |
| 3-methylcrotonyl-CoA | (CH3)2C==CHCOSCoA;an intermediate in the degradation of l-leucine; accumulates in a deficiency of 3-methylcrotonyl-CoA carboxylase. 3-methylcrotonyl-CoA carboxylase, an enzyme in the pathway of l-leucine degradation that catalyses the reaction of 3-methylcrotonyl-CoA with CO2, ATP, and water to form ADP, orthophosphate, and 3-methylglutaconyl-CoA; a deficiency of this enzyme causes episodes of severe metabolic acidosis. (05 Mar 2000) |
| 3-methylglutaconyl-CoA hydratase | <enzyme> An enzyme that catalyses the reaction of trans-3-methylglutaconyl-CoA and water to form 3-hydroxy-3-methylglutaconyl-CoA; this enzyme participates in the pathway for l-leucine degradation; a deficiency of this enzyme will result in 3-methylglutaconic aciduria. (05 Mar 2000) |
| 3-oxoacid-CoA transferase | <enzyme> An enzyme catalyzing the reversible conversion of acetoacetyl-CoA and succinate into succinyl-CoA and acetoacetate; malonyl-CoA can substitute for succinyl-CoA and a few other 3-oxo acids for the acetoacetate; an important step in order for the ketone bodies to serve as a fuel for extrahepatic tissues. Synonym: 3-ketoacid-CoA transferase, acetoacetyl-succinic thiophorase. (05 Mar 2000) |
| 3-oxobutyryl-CoA reductase | <enzyme> Nadh-dependent, (s)-specific enzyme from clostridium tyrobutyricum; n-terminal amino acid sequence given in first source Registry number: EC 1.1.1.- (26 Jun 1999) |
| 4-halobenzoate-CoA ligase | <enzyme> Involved in conversion of 4-chlorobenzoate to 4-hydroxybenzoate by pseudomonas sp. Cbs3; 115 kD; acts on 4-chloro-, 4-bromo-, 4-iodobenzoate most effectively; 16 n-terminal amino acid sequence determined, with 3 questions, in first source Registry number: EC 6.2.1.- Synonym: 4-chlorobenzoate-CoA ligase, 4-cba-CoA ligase, 4-chlorobenzoate-coenzyme a ligase (26 Jun 1999) |
| 4-hydroxybenzoyl-CoA hydrolase | <enzyme> Final enzyme in the degradation of 4-chlorobenzoic acid by pseudomonas; liberates 4-hydroxybenzoic acid; amino acid sequence has been determined Registry number: EC 3.1.2.- Synonym: 4-hydroxybenzoyl-coenzyme a thioesterase, 4-hba-CoA thioesterase (26 Jun 1999) |
| 4-hydroxybutyrate CoA-transferase | <enzyme> Forms 4-hydroxybutyryl-CoA from 4-hydroxybutyrate and acetyl-CoA Registry number: EC 2.8.3.- Synonym: 4-hydroxybutyrate coenzyme a transferase (26 Jun 1999) |
| 4-hydroxybutyryl-CoA dehydratase | <enzyme> Forms vinylacetyl-CoA from 4-hydroxybutyryl-CoA Registry number: EC 4.2.1.- Synonym: gamma-hydroxybutyryl-CoA dehydratase (26 Jun 1999) |
| 5-hydroxyvalerate CoA-transferase | <enzyme> Catalyses the formation of 5-hydroxyvaleryl-CoA from 5-hydroxyvalerate and acetyl-CoA; also acts on propionate and 5-hydroxy-2-pentenoate Registry number: EC 2.8.3.- (26 Jun 1999) |
| 5-hydroxyvaleryl-CoA dehydratase | <enzyme> Contains fad; bifunctional enzyme which catalyses reversible dehydration of 5-hydroxyvaleryl-CoA to 4-pentenoyl-CoA Registry number: EC 4.2.1.- Synonym: 5hvc-dehydratase, 5-hydroxyvaleryl-CoA dehydratase-dehydrogenase (26 Jun 1999) |