Enzymic depolymerization of macromolecular heparin as a factor in control of lipoprotein lipase activity.

Macromolecular heparin from rat skin shows poor lipoprotein lipase-releasing activity in vivo and is a potent inhibitor of rat-heart lipoprotein lipase in vitro. Rat-skin heparin is depolymerized by incubation with the 100,000 x g supernatant from a sonicated homogenate of rat small intestine. The depolymerized products, fractionated by gel filtration, range from inhibitors to activators of lipoprotein lipase as molecular size decreases. Depolymerized rat heparin in the same molecular size range as commercial heparin from pig intestinal mucosa has about two-thirds the activity of the commercial preparation, both in vivo and in vitro.