3.4.23.32 D43A the mutant has approximately 20% of the original activity 3.4.23.32 E136A mutant loses the ability for self-activation and cleavage of the propeptide. Mutant has no peptidase activity 3.4.23.32 Q53A mutant loses the ability for self-activation and cleavage of the propeptide. Mutant has no peptidase activity 3.4.23.32 Q53E mutant loses the ability for self-activation and cleavage of the propeptide. Mutant has no peptidase activity