Stabilization of bovine trypsin by reductive methylation

Reductive methylation has little or no detectable effect on the catalytic or physicochemical properties of bovine trypsin but reduces its susceptibility to autolysis. Increased stability after methylation appears to result from the conversion of trypsin-susceptible lysine residues to trypsin-resistant ε-N,N-dimethyllysine residues. Reductively methylated trypsin is easily prepared and may be useful in place of trypsin where autolysis is otherwise difficult to control.