title: Topographical localization of peroxisomal acyl-CoA ligases: differential localization of palmitoyl-CoA and lignoceroyl-CoA ligases.
abstract: We found that peroxisomal lignoceroyl-CoA ligase, like palmitoyl-CoA ligase, is present in the peroxisomal membrane whereas the peroxisomal beta-oxidation enzyme system is localized in the matrix. To further define the role of peroxisomal acyl-CoA ligases (membrane component) in providing acyl-CoA for peroxisomal beta-oxidation, we examined the transverse topographical localization of enzymatic sites of palmitoyl-CoA and lignoceroyl-CoA ligases in the peroxisomal membranes. The disruption of peroxisomes by various techniques resulted in the release of a "latent" pool of lignoceroyl-CoA ligase activity while palmitoyl-CoA ligase activity remained the same. Proteolytic enzyme treatment inhibited palmitoyl-CoA ligase activity in intact peroxisomes but had no effect on lignoceroyl-CoA ligase activity. Lignoceroyl-CoA ligase activity was inhibited only if peroxisomes were disrupted with detergent before trypsin treatment. Antibodies to palmitoyl-CoA ligase and to peroxisomal membrane proteins (PMP) inhibited palmitoyl-CoA ligase in intact peroxisomes, and no pool of "latent" activity appeared when antibody-treated peroxisomes were disrupted with detergent. 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 lignoceroyl-CoA ligase is on the luminal surface of peroxisomal membranes. This implies that palmitoyl-CoA is synthesized on the cytoplasmic surface and is then transferred to the matrix through the peroxisomal membrane for beta-oxidation in the matrix.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston 29425.
authors.forename: O
authors.initials: O
authors.lastname: Lazo
authors.forename: M
authors.initials: M
authors.lastname: Contreras
authors.forename: I
authors.initials: I
authors.lastname: Singh
mesh_terms: D000214:Acyl Coenzyme A / Q000032:analysis*; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002462:Cell Membrane / Q000201:enzymology; D003066:Coenzyme A Ligases / Q000032:analysis*; D008099:Liver / Q000201:enzymology*; D008830:Microbodies / Q000201:enzymology*; D010171:Palmitoyl Coenzyme A / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D000098859:Long-Chain-Fatty-Acid-CoA Ligase
chemical_list: D000214:Acyl Coenzyme A; D000906:Antibodies; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D010171:Palmitoyl Coenzyme A; D003066:Coenzyme A Ligases; C044125:lignoceroyl-CoA ligase; C090799:FAA2 protein, S cerevisiae; D000098859:Long-Chain-Fatty-Acid-CoA Ligase