Clearing factor and lipase

Abstract

In vitro studies on the action of clearing factor prove that neither ali-esterase nor lipase are necessary for its action. Clearing factor acts in the almost complete absence of both enzymes. The behavior of clearing factor towards various inhibitors of ali-esterase and lipase, together with the liberation of fatty acids during clearing, indicates that clearing factor might be a new type of enzyme (a lipoproteinase) which possesses some characteristics of both ali-esterase and lipase without being identical with either. In vivo studies on the production of clearing factor showed that it can be produced in the absence of ali-esterases, but that in pancreatectomized dogs a good correlation existed between the lipase activity of the plasma and the production of clearing factor after injection of heparin. The possible implications of these findings are discussed in relation to the problem of atherosclerosis.