CHARACTERIZATION OF A NONSPECIFIC LIPID TRANSFER PROTEIN ASSOCIATED WITH THE PEROXISOMAL MEMBRANE OF THE YEAST, SACCHAROMYCES-CEREVISIAE

A lipid transfer protein with a broad substrate specificity is associa ted with the peroxisomal membrane of the yeast Saccharomyces cerevisia e. The protein catalyzes in vitro the transfer of various phospholipid s, phosphatidylinositol and phosphatidylserine bring translocated at t he highest rates. The transfer protein can be released from peroxisoma l membranes by treatment with 0.25 M KCl and highly enriched using con ventional chromatographic techniques. It is inactivated by heat, deter gents, divalent cations and proteinases. During various steps of purif ication this lipid transfer protein co-fractionated with peroxisomal a cyl-CoA oxidase (Pox1p). In a pox1 disruptant peroxisomal lipid transf er activity was still present, although at a reduced level. The peroxi somal lipid transfer protein from the pox1 mutant exhibited different chromatographic properties as compared to the wild-type strain suggest ing that acyl-CoA oxidase and the peroxisomal lipid transfer protein m ay form a complex.