steady-state and pre-steady-state data for h.u . kallikrein catalyzed hydrolysis of n alpha-carbobenzoxy-l-lysine p-nitrophenyl ester ( zlysonp ) and of n alpha-carbobenzoxy-l-alanine p-nitrophenyl ester ( zalaonp ) in the presence and absence of ethylamine and acetamidine have been obtained under various conditions and have been analyzed in the framework of the minimum three-step mechanism : ( formula see text ) the ph dependencies of the kinetic parameters for the hydrolysis of zlysonp and zalaonp in the presence of saturating levels of ethylamine and acetamidine show that at acid ph values ( less than or equal to 4 ) the k3 step ( deacylation ) is rate limiting in catalysis , whereas for ph values greater than or equal to 6 , k2 ( acylation ) becomes rate limiting .
C0022478
kallikrein
C0020291
hydrolysis