Deacylation Rate Constants of Acylated Human and Porcine Plasmins

Abstract

Deacylation rate constants, k3, were measured for the human acyl-plasmins which contain in the acyl portion, RCO, the R groups methyl, cyclohexyl, p-nitrophenyl, isobutyl, trans-isopropenyl, phenyl, a-naphthyl, anisoyl and p-guanidinophenyl. Values of k3 were also determined for the porcine acylplasm ins which have R = methyl, cyclohexyl, phenyl, anisoyl and p-guanidinophenyl. In general, for both the human and porcine acyl-plasm ins, k3 decreased as the electron-donating ability of the acyl group increased. At 25°C, the human acyl-plasmin with R = methyl has the highest k3, 1·06 ± 0·05 X 10-2 S-I, and the porcine acyl-plasmin with R = p-guanidinophenyl the lowest k3, 1·4 ± 0·1 X 10-6 S-I.