Purification and characterization of lipoprotein lipase from human heart

Human heart lipoprotein lipase was purified by affinity chromatography on heparin-Sepharose 4B. When crude extracts of heart acetone powder were applied to columsn, about 40% of total lipase activity was bound to the gel and then eluted with 1.5 M NaCl. At this stage the eluted enzyme was purified 1900-fold. Disc gel electrophoresis yielded a single protein band corresponding with lipolytic activity. Minimum molecular weight of the protein was 60,000 as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The purified enzyme was highly unstable; however, its activity could be partially stabilized at --20C by bovine serum albumin, glycerol, or ethylene glycol. The activity of the purified enzyme (i) had a pH optimum between 7.8 and 8.0; (ii) required serum for full enzymatic activity; apoC-II could be substituted for serum; (iii) was inhibited by by apoC-I in the presence of activated substrate; (iv) was markedly inhibited by NaCl; and (v) was stimulated by heparin.