On the renin-like activity of Candida proteinases and activation of blood coagulation in vitro.

Several secretory acid proteinases from C. albicans and C. tropicalis as well as membrane extracts from two strains of C. albicans were compared for their renin-like activity and for their ability to activate blood coagulation. The highest renin-like activity as measured fluorometrically, was found in the membrane extract of C. albicans 113, it accounted for approximately a tenth of the activity of pure human renin. Activation of blood coagulation by acid Candida proteinases is due to the trypsinogen kinase effect, it was detected preferentially at the level of factor X (Stuart-Prower). Conversion of factor X at rates sufficiently rapid to be of biological significance was effected by several proteinases tested. The highest activity was found in the membrane extract of C. albicans CBS-2730 and involves a proteinase of the serine type. Both renin-like activity and conversion of factor X are examples of limited proteolysis; they are discussed with respect to strain-specific pathogenicity in opportunistic yeasts.