Human protein C and activated protein C Components of the human anticoagulation system.

Protein C, the zymogen form of the anticoagulant protein, activated protein C, is a member of the vitamin K-dependent class of proteins that function in generation and control of formation of blood clots. This plasma protein consists of a series of domain regions that are qualitatively similar to those present in human coagulation factors VII, IX, and X, and that appear to be related to specific properties of these proteins. With the recent advent of rigorous application of genetic engineering strategies to this system, and the continuing discoveries and characterization of genotypes and phenotypes of protein C in patients, great progress has been made in understanding structure-function relationships of protein C and activated protein C. This review is a summary and synthesis of recent pertinent studies with an emphasis on these topics.