The CoA esters of 2-methyl-branched chain fatty acids and of the bile acid intermediates di- and trihydroxycoprostanic acids are oxidized by one single peroxisomal branched chain acyl-CoA oxidase in human liver and kidney.
Rat liver peroxisomes contain three acyl-CoA oxidases: palmitoyl-CoA oxidase, which oxidizes the CoA esters of straight chain fatty acids and prostaglandins; pristanoyl-CoA oxidase, which oxidizes the CoA esters of 2-methyl-branched fatty acids (e.g. pristanic acid); and trihydroxycoprostanoyl-CoA oxidase, which oxidizes the CoA esters of the bile acid intermediates di- and trihydroxycoprostanic acids (Van Veldhoven, P. P., Vanhove, G., Asselberghs, S., Eyssen, H. J., and Mannaerts, G. P. (1992) J. Biol. Chem. 267, 20065-20074). In the present report we demonstrate that human liver peroxisomes contain only two acyl-CoA oxidases: palmitoyl-CoA oxidase, which oxidizes the CoA esters of straight chain fatty acids and prostaglandins, and a novel branched chain acyl-CoA oxidase, which oxidizes the CoA esters of 2-methyl-branched fatty acids as well as those of the bile acid intermediates (which also possess a 2-methyl substitution in their side chains). The branched chain acyl-CoA oxidase was purified to near homogeneity by means of column chromatography. It appeared to be a 70-kDa monomeric protein that did not cross-react with antisera raised against rat palmitoyl-CoA oxidase and pristanoyl-CoA oxidase. No indication was found for the presence of a separate trihydroxycoprostanoyl-CoA oxidase in human liver. The branched chain acyl-CoA oxidase was present also in human kidney, suggesting that it is expressed in other extrahepatic tissues as well. Our results explain a number of clinical-chemical observations made in certain cases of peroxisomal beta-oxidation disorders.
Katholieke Universiteit Leuven, Afdeling Farmacologie, Belgium.
G F
GF
Vanhove
P P
PP
Van Veldhoven
M
M
Fransen
S
S
Denis
H J
HJ
Eyssen
R J
RJ
Wanders
G P
GP
Mannaerts
D000214:Acyl Coenzyme A / Q000378:metabolism; D000328:Adult; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D002845:Chromatography; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006882:Hydroxyapatites; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008830:Microbodies / Q000201:enzymology*; D008970:Molecular Weight; D010088:Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity; D015211:Zellweger Syndrome / Q000201:enzymology
D000214:Acyl Coenzyme A; D001647:Bile Acids and Salts; D006882:Hydroxyapatites; D017886:Durapatite; D010088:Oxidoreductases; C081094:branched chain acyl-CoA oxidase