title: Thiolase involved in bile acid formation.
abstract: The formation of cholic acid and chenodeoxycholic acid through cleavage of the side chains of CoA esters of 3alpha,7alpha,12alpha-trihydroxy-5beta-choles tan-26-oic acid and 3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acid is believed to occur in peroxisomes. Recently, we found a new peroxisomal enzyme, D-3-hydroxyacyl-CoA dehydratase/D-3-hydroxyacyl-CoA dehydrogenase bifunctional protein, and suggested that this bifunctional protein is responsible for the conversion of 3alpha,7alpha,12alpha-trihydroxy-5beta-cholest-2 4-en-26-oyl-CoA and 3alpha,7alpha-dihydroxy-5beta-cholest-24-en-26-oyl-CoA to their 24-oxo-forms. In the present study, the products of this bifunctional protein reaction were analyzed by gas chromatography-mass spectrometry, and the formation of 24-oxo-27-nor-cholestanes was confirmed. Previously, we found a new thiolase in Caenorhabditis elegans, P-44, and suggested that P-44 and sterol carrier protein x, a peroxisomal protein, constitute a second group of 3-oxoacyl-CoA thiolases. The production of cholic acid and chenodeoxycholic acid from the precursors on incubation with the bifunctional protein and sterol carrier protein x or P-44 was confirmed by gas chromatography.
authors.affiliation: Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima.
authors.forename: M
authors.initials: M
authors.lastname: Bun-ya
authors.forename: M
authors.initials: M
authors.lastname: Maebuchi
authors.forename: T
authors.initials: T
authors.lastname: Kamiryo
authors.forename: T
authors.initials: T
authors.lastname: Kurosawa
authors.forename: M
authors.initials: M
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Tohma
authors.forename: L L
authors.initials: LL
authors.lastname: Jiang
authors.forename: T
authors.initials: T
authors.lastname: Hashimoto
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases; D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000101:Acetyl-CoA C-Acetyltransferase / Q000378:metabolism*; D000818:Animals; D001647:Bile Acids and Salts / Q000096:biosynthesis* / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000201:enzymology; D002352:Carrier Proteins / Q000378:metabolism; D004746:Enoyl-CoA Hydratase; D006836:Hydro-Lyases / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D009097:Multienzyme Complexes / Q000378:metabolism; D064029:Peroxisomal Multifunctional Protein-2; D010940:Plant Proteins; D051381:Rats; D013261:Sterols / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D002352:Carrier Proteins; D007527:Isoenzymes; D009097:Multienzyme Complexes; D010940:Plant Proteins; D013261:Sterols; C072087:sterol carrier proteins; D015067:17-Hydroxysteroid Dehydrogenases; D015094:3-Hydroxyacyl CoA Dehydrogenases; C491286:Hsd17b4 protein, rat; D000101:Acetyl-CoA C-Acetyltransferase; D006836:Hydro-Lyases; D064029:Peroxisomal Multifunctional Protein-2; D004746:Enoyl-CoA Hydratase