the ratio r equal to knbs22-/k4-py-s-s-4-py provides an index of the catalytic-site solvation properties of the four cysteine proteinases and varies markedly from one enzyme to another , being 0.80 for papaya peptidase a ( 0.86 for the model thiol , 2-mercaptoethanol ) , 29 for actinidin , 0.18 for ficin and 0.015 for papain .
C2717970
cysteine proteinases
C0030940
peptidase