Substituted N-methyl-N-nitrosoanilines are found to function as stable, potent, nitrosating agents for S-nitrosation and inactivation of cysteine proteases such as papain, bromelain and aldehyde dehydrogenase under physiological conditions in a time and concentration dependent manner. Spectroscopic studies on the reaction products have proved that the mechanism of the inactivation is a S-nitrosation of the protein.
