Platelet Factor 4: An Inhibitor of Collagenase

Abstract
Human platelet factor 4 (PF4) is known to bind to heparin and inhibit its anticoagulant effect. This factor also inhibits the enzyme collagenase derived from cultured human skin and collagenase extracted from human granulocytes. The addition of heparin to the PF4-collagenase assay system has no effect on the observed inhibition of collagenase. Thus PF4 inhibits collagenase, in addition to neutralizing heparin.