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Identification and purification of a peroxisomal branched chain fatty acyl-CoA oxidase
Ist Teil von
The Journal of biological chemistry, 1991-12, Vol.266 (36), p.24676-24683
Ort / Verlag
Bethesda, MD: American Society for Biochemistry and Molecular Biology
Erscheinungsjahr
1991
Link zum Volltext
Quelle
MEDLINE
Beschreibungen/Notizen
Isoprenoid (branched) fatty acids such as pristanic acid can be degraded via beta-oxidation in peroxisomes. We synthesized
2-methylpalmitoyl-CoA as a model substrate in order to study the first step of the peroxisomal beta-oxidation of branched
fatty acids, catalyzed by an acyl-CoA oxidase. 2-Methylpalmitoyl-CoA oxidase activity was found in rat liver homogenates.
Subcellular fractionation demonstrated that the oxidase was confined to peroxisomes. 2-Methylpalmitoyl-CoA oxidase was also
present in kidney and intestine. It was not induced in liver or in the extrahepatic tissues by treatment of rats with peroxisome
proliferators or by feeding diets containing excess isoprenoids. The enzyme was partially purified together with palmitoyl-CoA
oxidase and trihydroxycoprostanoyl-CoA oxidase by heat treatment and ammonium sulfate fractionation of liver extracts. The
partially purified preparation was chromatographed on various columns. 2-Methylpalmitoyl-CoA oxidase could be separated from
the inducible (by peroxisome proliferators) palmitoyl-CoA oxidase and from trihydroxycoprostanoyl-CoA oxidase, but it always
coeluted with the noninducible palmitoyl-CoA oxidase, recently described by us (Schepers, L., Van Veldhoven, P. P., Casteels,
M., Eyssen, H. J., and Mannaerts, G. P. (1990) J. Biol. Chem. 265, 5242-5246). 2-Methylpalmitoyl-CoA oxidase was purified
to near homogeneity in three chromatographic steps (anion exchange, hydroxylapatite, and gel filtration). Its apparent molecular
mass is approximately 415 kDa, and it consists of identical subunits of approximately 70 kDa. The enzyme oxidized 2-methylpalmitoyl-CoA
twice as rapidly as palmitoyl-CoA and pristanoyl-CoA as rapidly as palmitoyl-CoA, so that it can be considered as a branched
fatty acyl-CoA oxidase. Since pristanoyl-CoA is one of its naturally occurring substrates we propose to name this enzyme pristanoyl-CoA
oxidase.