Comparison of properties of cancer procoagulant and human amnion-chorion procoagulant.

Cysteine proteinases that initiate coagulation in the absence of factor VII have been isolated from rabbit V2 carcinoma and from human amnion-chorion. Many of their biochemical properties, including a molecular weight of 68 000 and inhibition by iodoacetamide and mercury, are the same. In the paper we compare the isoelectric point, the amino acid composition and the carbohydrate content of human amnion-chorion procoagulant and cancer procoagulant. With the exception of minor differences in the amino acid composition, attributable in part to differences in species, the two proteins are closely homologous.