Thiolase involved in bile acid formation.
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.
Bun-ya
M
M
Faculty of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima.
Maebuchi
M
M
Kamiryo
T
T
Kurosawa
T
T
Sato
M
M
Tohma
M
M
Jiang
L L
LL
Hashimoto
T
T
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
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