Separation and Characterization of Two Triglyceride Lipase Activities from Human Post-Heparin Plasma

Abstract

The lipase activities of post-heparin plasma have been shown to hydrolyze many classes of lipids, including: a) triglycerides (TG), diglycerides (DG) and monoglycerides (MG) (Shore and Shore, 1960; Greten et al., 1969; Fielding, 1972; Greten, 1972), b) phospholipids (Vogel and Zieve, 1964; Vogel and Bierman, 1967) and c) long-chain fatty acyl coenzyme A derivatives (Jansen and Hulsman, 1973). Attempts to physically separate enzymes specific for the hydrolysis of each of these lipid classes have been unsuccessful. Recent studies have shown that at least two triglyceride lipase activities exist in post-heparin plasma (LaRosa et al., 1972; Greten et al., 1972; Fielding, 1970). They have been characterized after partial purification from swine post-heparin plasma (Ehnholm et al., 1972). One of these was similar in its characteristics to the lipoprotein lipase of adipose tissue (Bensadouw et al., unpublished) and the other differed from lipoprotein lipase in its lack of activation by plasma cofactor and in being stimulated rather than inhibited by exposure to solutions high in ionic strength. This hydrolase was also active against phospholipids. The techniques used successfully in the separation of swine triglyceride lipase have now been applied to the study of human post-heparin plasma.