Premium
Peroxisomal β‐oxidation of 2‐methyl‐branched acyl‐CoA esters stereospecific recognition of the 2 S ‐methyl compounds by trihydroxycoprostanoyl‐CoA oxidase and pristanoyl‐CoA oxidase
Author(s) -
Van Veldhoven Paul P.,
Croes Kathleen,
Asselberghs Stanny,
Herdewijn Piet,
Mannaerts Guy P.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00508-x
Subject(s) - peroxisome , oxidase test , chemistry , stereospecificity , enzyme , biochemistry , stereoselectivity , stereochemistry , cholesterol oxidase , catalysis , gene
Trihydroxycoprostanoyl‐CoA oxidase and pristanoyl‐CoA oxidase, purified from rat liver, both catalyse the desaturation of 2‐methyl‐branched acyl‐CoAs. Upon incubation with the pure isomers of 2‐methylpentadecanoyl‐CoA, both enzymes acted only on the S ‐isomer. The R ‐isomer inhibited trihydroxycoprostanoyl‐CoA oxidase but did not affect pristanoyl‐CoA oxidase. The activity of both enzymes was suppressed by 3‐methylheptadecanoyl‐CoA. Valproyl‐CoA and 2‐ethylhexanoyl‐CoA, however, did not influence the oxidases. Although only one isomer of 25 R , S ‐trihydroxycoprostanoyl‐CoA was desaturated by trihydroxycoprostanoyl‐CoA oxidase, isolated peroxisomes were able to act on both isomers, suggesting the presence of a racemase in these organelles. Given the opposite stereoselectivity of the 26‐cholesterol hydroxylase and of the oxidase, the racemase is essential for bile acid formation.