A plasma inhibitor of triglyceride and cholesteryl ester transfer activities

An inhibitor of triglyceride and cholesteryl ester transfer activities has been identified in the plasmas of several animal species. The inhibitor in human plasma has been separated from lipid transfer protein by chromatography on phenyl-Sepharose and CM-cellulose. The inhibitor is characterized as a protein with Mr approximately 35,000 and an isoelectric point of 4 or less. The inhibitor protein decreased the transfer of both triglyceride and cholesteryl ester between all pairs of very low, low, and high density lipoproteins. Although under most conditions the inhibition of triglyceride and cholesteryl ester transfer was similar, the degree of inhibition of lipid transfer was dependent on the lipoprotein pair studied.