Lipid transfer protein from Manduca sexta hemolymph.

A hemolymph lipid transfer protein (LTP) was isolated from the tobacco hornworm, Manduca sexta. LTP catalyzes net lipid transfer between isolated hemolymph lipoproteins in vitro. An isolation procedure employing density gradient ultracentrifugation and gel permeation chromatography produced a purified protein. LTP is a very high density lipoprotein with a particle Mr greater than 500,000. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that LTP is comprised of two apoproteins: apoLTP-I (Mr approximately 320,000) and apoLTP-II (Mr approximately 85,000). LTP may have a physiological role in altering the lipid content and composition of the major hemolymph lipoprotein, lipophorin.