Expression of biologically active hormone‐sensitive lipase in mammalian (COS) cells

Abstract

CDNAs encoding rat adipose tissue hormone‐sensitive lipase were expressed in COS cells, under the control of the SV40 promoter to half the level in rat adipocytes, the richest native source of the enzyme. A cDNA lacking most of the long 5′‐untranslated region of the full‐length rat hormone‐sensitive lipase cDNA was, with regard to the lipase activity, on the average 70% more efficiently expressed than the full‐length cDNA. The recombinant protein was almost identical to hormone‐sensitive lipase of rat adipose tissue with respect to specific activity, susceptibility to inhibitors, molecular size, phosphorylation and activation by cyclic AMP‐dependent protein kinase. The described eukaryotic expression system will allow analysis of effects of amino acid substitutions introduced into the lipase molecule by site‐directed mutagenesis.