Table 3: Effect of protease inhibitors, metal ions, and solvents on proteolytic activity of B. subtilis MA21.

SubstanceFinal concentrationRelative activity (%)Final concentrationRelative activity (%)

Control01000100
β-mercaptoethanol5 mM481 mM70
PMSF5 mM01 mM0
EDTA5 mM131 mM96
SDS0.5%250.1%99
ZnCl210 mM925 mM93
MgCl210 mM225 mM98
CuSO410 mM235 mM73
Urea10 mM245 mM52
HgCl210 mM275 mM37
CaCl210 mM655 mM142
BaCl210 mM295 mM69
Guanidin HCl10 mM425 mM49
MnCl210 mM645 mM67
Methanol1%920.5%99
Ethanol1%920.5%97
DMSO1%780.5%96
Isopropanol1%980.5%101
Tween 201%780.5%86
Triton X1001%570.5%133