A SPHINGOMYELIN-TRANSFERRING PROTEIN FROM CHICKEN LIVER - USE OF PYRENE-LABELED PHOSPHOLIPID

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. Specifici ty was established by use of phospholipids that carry a pyrene-labeled acyl chain. Based on the N-terminal sequence and Western blot analysi s we conclude that this protein is an isoform of the PI-transfer prote in. At increasing length of the pyrene-labeled acyl chain, the isoform expresses a high activity toward SM, a low activity toward PI, and vi rtually no activity toward PC.