Purification and properties of a phospholipid transfer protein from Rhodopseudomonas sphaeroides

A phospholipid transfer protein has been purified 280-fold from Rhodopseudomonas sphaeroides when compared to the 40-70% ammonium sulfate fraction derived from the crude cell supernatant in which the activity was originally found (Cohen, L.K., Lueking, D.R., and Kaplan, S. (1979) J. Biol. Chem. 254, 721-728). When compared to the crude cell lysate, the activity has been purified approximately 1,400-fold with a recovery of 12.5%. The active protein is a monomer with a molecular weight of 26,500, as estimated by sedimentation velocity and sedimentation equilibrium, and 27,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein can transfer all phospholipid species tested with the order of efficiency of transfer being phosphatidylglycerol greater than phosphatidylcholine greater than phosphatidylethanolamine.