Glycolipid transfer protein from bovine brain

Publisher Website
Google Scholar
Abstract
Glycolipid transfer protein from bovine brain was purified partially by ammonium sulfate precipitation, CM-52 ion-exchange and Sephadex G-75 column chromatography. Both pyrene-labeled and tritium-labeled glucocerebrosides were used to study the kinetics of protein-mediated transfer between donor and acceptor vesicles. Protein accelerates glucocerebroside transfer but does not accelerate phospholipid transfer. In colyophilized small sonicated vesicles (10% glucocerebroside, 90% 1-palmitoyl-2-oleoylphosphatidylcholine) about 2/3 of the glycolipid is transferred in 2 h and the remaining 1/3 does not transfer (up to 5 h). For donor and acceptor vesicles made of dipalmitoylphosphatidylcholine or 1-palmitoyl-2-oleoylphosphatidylcholine, glucocerebroside (10% in donors) is transferred rapidly only when both the donor and acceptor matrix phospholipids are in the liquid-crystalline state. If either donor or acceptor vesicles are in the gel state, transfer protein mediated transfer is much reduced. The amount of transfer protein bound specifically to glucocerebroside-containing vesicles is nearly equal above and below the matrix phospholipid phase transition temperature. Bound protein transfers glucocerebroside upon addition of acceptor vesicles.