A novel acyl-CoA oxidase that can oxidize short-chain acyl-CoA in plant peroxisomes.
Short-chain acyl-CoA oxidases are beta-oxidation enzymes that are active on short-chain acyl-CoAs and that appear to be present in higher plant peroxisomes and absent in mammalian peroxisomes. Therefore, plant peroxisomes are capable of performing complete beta-oxidation of acyl-CoA chains, whereas mammalian peroxisomes can perform beta-oxidation of only those acyl-CoA chains that are larger than octanoyl-CoA (C8). In this report, we have shown that a novel acyl-CoA oxidase can oxidize short-chain acyl-CoA in plant peroxisomes. A peroxisomal short-chain acyl-CoA oxidase from Arabidopsis was purified following the expression of the Arabidopsis cDNA in a baculovirus expression system. The purified enzyme was active on butyryl-CoA (C4), hexanoyl-CoA (C6), and octanoyl-CoA (C8). Cell fractionation and immunocytochemical analysis revealed that the short-chain acyl-CoA oxidase is localized in peroxisomes. The expression pattern of the short-chain acyl-CoA oxidase was similar to that of peroxisomal 3-ketoacyl-CoA thiolase, a marker enzyme of fatty acid beta-oxidation, during post-germinative growth. Although the molecular structure and amino acid sequence of the enzyme are similar to those of mammalian mitochondrial acyl-CoA dehydrogenase, the purified enzyme has no activity as acyl-CoA dehydrogenase. These results indicate that the short-chain acyl-CoA oxidases function in fatty acid beta-oxidation in plant peroxisomes, and that by the cooperative action of long- and short-chain acyl-CoA oxidases, plant peroxisomes are capable of performing the complete beta-oxidation of acyl-CoA.
Hayashi
H
H
Department of Cell Biology, National Institute for Basic Biology, Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
De Bellis
L
L
Ciurli
A
A
Kondo
M
M
Hayashi
M
M
Nishimura
M
M
D042964:Acyl-CoA Dehydrogenase; D044944:Acyl-CoA Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000254:growth & development; D018076:DNA, Complementary; D008830:Microbodies / Q000201:enzymology*; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D018076:DNA, Complementary; D044944:Acyl-CoA Dehydrogenases; D042964:Acyl-CoA Dehydrogenase