IDENTIFICATION OF -3-ALPHA,7-ALPHA-DIHYDROXY-5-BETA-CHOLEST-24-ENOIC ACID AND -3-ALPHA,7-ALPHA,24-TRIHYDROXY-5-BETA-CHOLESTANOIC ACID AS INTERMEDIATES IN THE CONVERSION OF 3-ALPHA,7-ALPHA-DIHYDROXY-5-BETA-CHOLESTANOIC ACID TO CHENODEOXYCHOLIC ACID IN RAT-LIVER HOMOGENATES
M. Une et al., IDENTIFICATION OF -3-ALPHA,7-ALPHA-DIHYDROXY-5-BETA-CHOLEST-24-ENOIC ACID AND -3-ALPHA,7-ALPHA,24-TRIHYDROXY-5-BETA-CHOLESTANOIC ACID AS INTERMEDIATES IN THE CONVERSION OF 3-ALPHA,7-ALPHA-DIHYDROXY-5-BETA-CHOLESTANOIC ACID TO CHENODEOXYCHOLIC ACID IN RAT-LIVER HOMOGENATES, Journal of lipid research, 35(4), 1994, pp. 620-624
Studies of chemical structure of the intermediates in the biosynthetic
sequence between 3 alpha,7 alpha-dihydroxy-5 beta-cholestanoic acid (
DHCA) and chenodeoxycholic acid have been undertaken. Radiolabeled DHC
A was incubated with a rat liver preparation. The reaction products we
re converted to the p-bromophenacyl esters, and analyzed by reversed-p
hase high performance liquid chromatography. Under the conditions used
, the radioactivity was found in (24E)-3 alpha, 7 alpha-dihydroxy-5 be
ta-cholest-24-enoic acid (31%) and (24R, 25S)-3 alpha,(7 alpha,(24-tri
hydroxy-5 beta-cholestanoic acid (7%) along with the starting material
(62%). Neither the 24Z isomer of the alpha,beta-unsaturated bile acid
nor the other three isomers of the beta-hydroxy bile acid were detect
ed. The findings support the proposed pathway for the side chain cleav
age in chenodeoxycholic acid biosynthesis, which is thought to be iden
tical to that of cholic acid biosynthesis.