Inhibition by FOY of kininase II in human plasma

In this investigation we studied the inhibitory effect of FOY S 983 (gabexate mesilate) and FOY S 980 (camostate mesilate) on the kininase II activity in human plasma in vitro. Both compounds were able to inhibit kinase II, however, compared to captopril or EDTA only very weakly. The inhibitory effect of FOY S 983 or FOY S 980 could be diminished neither by NaOH-induced hydrolysis of the inhibitor nor by dialysis or ultrafiltration, but could be clearly reduced by dialysis against ZnCl2 solution. The inhibition of kininase II activity in human plasma by FOY S 983 was due to its 6-guanidinocaproate component probably acting as Zn2+-complexing agent. The ethyl 4-hydroxybenzoate component of FOY S 983 had no inhibitory effect.