Substrate specificities of rat liver peroxisomal acyl-CoA oxidases: palmitoyl-CoA oxidase (inducible acyl-CoA oxidase), pristanoyl-CoA oxidase (non-inducible acyl-CoA oxidase), and trihydroxycoprostanoyl-CoA oxidase.
Rat liver peroxisomes contain three acyl-CoA oxidases:palmitoyl-CoA oxidase, pristanoyl-CoA oxidase, and trihydroxycoprostanoyl-CoA oxidase. The three oxidases were separated by anion-exchange chromatography of a partially purified oxidase preparation, and the column eluate was analyzed for oxidase activity with different acyl-CoAs. Short chain mono (hexanoyl-) and dicarboxylyl (glutaryl-)-CoAs and prostaglandin E2-CoA were oxidized exclusively by palmitoyl-CoA oxidase. Long chain mono (palmitoyl-) and dicarboxylyl (hexadecanedioyl-)-CoAs were oxidized by palmitoyl-CoA oxidase and pristanoyl-CoA oxidase, the former enzyme catalyzing approximately 70% of the total eluate activity. The very long chain lignoceroyl-CoA was also oxidized by palmitoyl-CoA oxidase and pristanoyl-CoA oxidase, the latter enzyme catalyzing approximately 65% of the total eluate activity. Long chain 2-methyl branched acyl-CoAs (2-methylpalmitoyl-CoA and pristanoyl-CoA) were oxidized for approximately 90% by pristanoyl-CoA oxidase, the remaining activity being catalyzed by trihydroxycoprostanoyl-CoA oxidase. The short chain 2-methylhexanoyl-CoA was oxidized by trihydroxycoprostanoyl-CoA oxidase and pristanoyl-CoA oxidase (approximately 60 and 40%, respectively, of the total eluate activity). Trihydroxycoprostanoyl-CoA was oxidized exclusively by trihydroxycoprostanoyl-CoA oxidase. No oxidase activity was found with isovaleryl-CoA and isobutyryl-CoA. Substrate dependences of palmitoyl-CoA oxidase and pristanoyl-CoA oxidase were very similar when assayed with the same (common) substrate. Since the two oxidases were purified to a similar extent and with a similar yield, the contribution of each enzyme to substrate oxidation in the column eluate probably reflects its contribution in the intact liver.
Van Veldhoven
P P
PP
Afdeling Farmacologie, Katholieke Universiteit Leuven, Belgium.
Vanhove
G
G
Assselberghs
S
S
Eyssen
H J
HJ
Mannaerts
G P
GP
D000214:Acyl Coenzyme A / Q000378:metabolism; D042962:Acyl-CoA Oxidase; D000818:Animals; D002852:Chromatography, Ion Exchange; D008099:Liver / Q000201:enzymology*; D008830:Microbodies / Q000201:enzymology*; D010088:Oxidoreductases / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity
D000214:Acyl Coenzyme A; D010088:Oxidoreductases; C028427:palmitoyl CoA oxidase; C066272:pristanoyl-CoA oxidase; D042962:Acyl-CoA Oxidase; C063427:trihydroxycoprostanoyl-CoA oxidase