Studies on Hormone-sensitive Lipase and Lipoprotein Lipase in Adipose Tissue

Abstract

Rat liver esterase [EC 3. 1. 1. 1] was purified to yield an electrophoretically homogeneous component. Anti-liver esterase antibody was prepared using this purified preparation. The antibody effectively precipitated the lipase [EC 3.1.1.3] and esterase activities of adipose tissue lipase fraction, and the esterase activity of the adipose tissue esterase fraction. Based on these and previous results, it is suggested that adipose tissue lipase is composed of esterase and lipid.

Anti-liver esterase antibody also precipitated both hormone-sensitive lipase and lipoprotein lipase of adipose tissue. The lipolytic activity of hormone-sensitive lipase was maximum at pH 6.8 in the absence of serum and at pH 8.0 in the presence of serum. The activity was markedly activated by serum, which stimulated the formation of an enzyme-substrate complex. In the presence of 1 M NaCl, serum did not activate lipase activity and the maximum activity remained at pH 6.8. The lipoprotein lipase activity was clearly inactivated by acetone treatment. From these results, it is suggested that hormone-sensitive lipase and lipoprotein lipase may be the same entity.