Characterization of triglyceride lipase activities in rat skeletal muscle

Abstract

Triglyceride lipase activity was determined in particulate and soluble fractions from rat skeletal muscle homogenates. The fractions exhibited an acid (pH 5,0) optimum with an impressive enhancement in the combined P17 100 fraction. Methylamine inhibited this acid lipase activity. A further lipase was observed with maximal activity at pH 7,0 and only a small enhancement in the combined P17 100 fraction and inhibition by diethyl p-nitrophenyl-phosphate but not by protamine sulfate. Lipoprotein lipase activity was identified by the following in vitro criteria: Stimulation of activity by serum, maximal activity at alkaline pH (pH 8,5 – 9,0) and inhibition of activity by NaCl and protamine sulfate. There was a definite enhancement of lipoprotein lipase activity in the bombined P17 100 fraction after the lipase activity has been washed out from the capillary bed with heparin.