A Sphingomyelin-transferring Protein from Chicken Liver. USE OF PYRENE-LABELED PHOSPHOLIPID

Abstract

A phospholipid transfer protein was purified from chicken liver which, in addition to phosphatidylinositol (PI) and phosphatidylcholine (PC), carries sphingomyelin (SM) between membranes. For comparison, the PI-transfer protein from chicken liver only carries PI and PC. Specificity was established by use of phospholipids that carry a pyrene-labeled acyl chain. Based on the N-terminal sequence and Western blot analysis we conclude that this protein is an isoform of the PI-transfer protein. At increasing length of the pyrene-labeled acyl chain, the isoform expresses a high activity toward SM, a low activity toward PI, and virtually no activity toward PC. A phospholipid transfer protein was purified from chicken liver which, in addition to phosphatidylinositol (PI) and phosphatidylcholine (PC), carries sphingomyelin (SM) between membranes. For comparison, the PI-transfer protein from chicken liver only carries PI and PC. Specificity was established by use of phospholipids that carry a pyrene-labeled acyl chain. Based on the N-terminal sequence and Western blot analysis we conclude that this protein is an isoform of the PI-transfer protein. At increasing length of the pyrene-labeled acyl chain, the isoform expresses a high activity toward SM, a low activity toward PI, and virtually no activity toward PC.