72 Topographical localization of Peroxisomal Acyl-CoA Ligases: Differential localization of Palmitoyl-CoA and Lignoceroyl-CoA Ligases

摘要

We found that peroxisomal licjnoceroyl-CoA ligase, like palmitoyl-CoA ligase, is present in the peroxisomal membrane. To further define the role of peroxisomal acyl-CoA ligases we examined the transverse topographical localization of enzymatic sites of palmitoyl-CoA and lignoceroyl-CoA ligases in the peroxisomal membranes. Proteolytic enzyme treatment irihibited palmitoyl-CoA ligase activity in intact peroxisomes and ligrraceroyl-CoA ligase activity was inhibited only if peroxisomes were disrupted prior to trypsin treatment. Antibodies to palmitoyl-CoA ligase and to peroxisomal membrane proteins (PMP) inhibited palmtoyl-CoA ligase in intact peroxisomes, and no pool of “latent” activity appeared when antibody-treated peroxisomes were disrupted. On the other hand, disruption of PMP antibody-treated peroxisomes with detergent resulted in the appearance of a “latent” pool of lignoceroyl-CoA ligase activity. These results demonstrate that the enzymatic site of palmitoyl-CoA ligase is on the cytoplasmic surface whereas that for ligncceroyl-CoA ligase is on the luminal surface of peroxisomal membranes. The implication of these findings to X-adrenoleukodystiuphy will be discussed.