A 25-hydroxylation pathway of cholic acid biosynthesis in man and rat.
AUTOR(ES)
Shefer, S
RESUMO
This paper describes a pathway of cholic acid synthesis, in man and in the rat, which involves 25-hydroxylated intermediates and is catalyzed by microsomal and soluble enzymes. The subcellular localization, stereospecificity, and other properties of the enzymes involved were studied with liver fractions of normolipidemic subjects, cerebrotendinous xanthomatosis patients, and rats. 5beta-Cholestane-3alpha,7alpha,12alpha,25-tetrol was converted to 5beta-cholestane-3alpha,7alpha,12alpha,24beta,25-pentol by the microsomal fraction in the presence of NADPH and O2. 5beta-Cholestane-3alpha,7alpha,12alpha,24alpha,25-pentol, 5beta-cholestane-3alpha,7alpha,12alpha,-23xi,25-pentol, and 5beta-cholestane-3alpha,7alpha,12alpha,25,26-pentol were also formed. In the presence of NAD, 5beta-cholestane-3alpha,7alpha,12alpha,24beta,25-pentol, but not the other 5beta-cholestanepentols formed, was converted to cholic acid by soluble enzymes in good yield. These experiments demonstrate the existence of a pathway for side-chain degradation in cholic acid synthesis which does not involve hydroxylation at C-26 or the participation of mitochondria.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=436733Documentos Relacionados
- Bile acid synthesis in man. In vivo activity of the 25-hydroxylation pathway.
- Cerebrotendinous xanthomatosis: a defect in mitochondrial 26-hydroxylation required for normal biosynthesis of cholic acid.
- Conversion of Cholesterol to Trihydroxycoprostanic Acid and Cholic Acid in Man*
- Amino acid modulation of renal phosphatidylcholine biosynthesis in the rat.
- Cholic Acid Biosynthesis: THE ENZYMATIC DEFECT IN CEREBROTENDINOUS XANTHOMATOSIS
