title: A survey of enzymes which generate or use acetoacetyl thioesters in rat liver.
abstract: Reactions that generate and remove acetoacetyl-CoA and acetoacetate were measured in mitochondria and cytosol of rat liver. The activities surveyed include acetoacetyl-CoA hydrolase, acetoacetyl-glutathione hydrolase, acetoacetyl-CoA:glutathione acyl transferase, 3-ketothiolases I and II, 3-hydroxy-3-methylglutaryl-CoA lyase and synthase, and acetoacetyl-CoA synthetase. Phosphocellulose chromatography shows that cytosol contains at least four acetoacetyl-CoA hydrolase activities, two of which do not coincide with 3-ketothiolases or 3-hydroxy-3-methylglutaryl-CoA lyase, while mitochondria contain at least three acetoacetyl-CoA hydrolase activities that overlap partially or completely with 3-ketothiolases and 3-hydroxy-3-methyl-glutaryl-CoA lyase. Two of the mitochondrial acetoacetyl-CoA hydrolase activities are not found in cytosol. Cytosol contains at least two and mitochondrial extracts at least six acetoacetyl-glutathione hydrolase activities. Mitochondria and cytosol both contain two isozymes of 3-ketoacyl-CoA thiolase (thiolases Ia and Ib). Chain length specificities show that the mitochondrial and cytosolic forms of thiolase Ia differ from each other. We report a new isozyme of 3-ketoacyl-CoA thiolase (thiolase I) in rat liver cytosol.
mesh_terms: D000090:Acetoacetates / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000031:analogs & derivatives* / Q000378:metabolism; D000102:Acetyl-CoA C-Acyltransferase / Q000378:metabolism; D000214:Acyl Coenzyme A; D000818:Animals; D003066:Coenzyme A Ligases / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D006904:Hydroxymethylglutaryl-CoA Synthase / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology; D007652:Oxo-Acid-Lyases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013869:Thiolester Hydrolases / Q000378:metabolism; D000099301:Hydroxyacylglutathione Hydrolase
chemical_list: D000090:Acetoacetates; D000105:Acetyl Coenzyme A; D000102:Acetyl-CoA C-Acyltransferase; D000214:Acyl Coenzyme A; D003066:Coenzyme A Ligases; D006904:Hydroxymethylglutaryl-CoA Synthase; D007652:Oxo-Acid-Lyases; D013869:Thiolester Hydrolases; D000099301:Hydroxyacylglutathione Hydrolase; C010667:acetoacetyl CoA; C023745:acetoacetyl-CoA hydrolase; C021410:3-hydroxy-3-methylglutaryl-coenzyme A lyase; C023747:acetoacetyl-CoA synthetase