Characterization of serum-stimulated lipoprotein lipase from bovine heart.

1. A triglyceride (TG) lipase is present in whole homogenate and tissue extracts of beef myocardium with characteristics of lipoprotein lipase (LPL); i.e., activity is stimulated by serum, inhibited by NaCl and protamine sulfate, the protein binds to heparin-Sepharose, and the enzyme has an alkaline pH optimum. 2. This TG lipase, eluted from heparin-Sepharose at 0.9-1.0 M NaCl, has an apparent mol. wt of 64 K daltons. Its primary mRNA is 3.7 kb. 3. Expression of LPL mRNA and enzyme activities are in the ratio of approximately 20:8:1 for hearts of mouse, rat and beef, respectively and correlate with r = +0.99.