Site of thrombin inactivation of the clearing factor system

¹ Arteriosclerosis Research Laboratory, St. Barnabas Hospital Research Foundation, and University of Minnesota School of Medicine, Minneapolis, Minnesota

A previous report has shown thrombin to markedly impair the activity of the human clearing factor system when triglyceride is used as the substrate. In an attempt to locate the site of the impairment, thrombin has been preincubated with selected, obligatory components of the clearing factor system. Subsequently the component is added to the enzyme system for activity assay. On this basis it has been possible to show that thrombin specifically destroys the lipoprotein lipase enzyme.