However, the MPH is reversibly inactivated by diethyl pyrocarbonate (DEPC) and the inactivation rate is 9.6 h~(-1). When adding neutralized hydroxylamine, the enzymatic activity of inactivated-MPH was restored to about 60% of initial activity.

• 然而二乙基焦磷酸酯对组氨酸侧链的化学修饰引起酶活性的大幅度的下降，其对酶活性的抑制率达到9.；6h~(-1)，当在酶的抑制体系中加了羟胺后，MPH的酶活力能够恢复到原来的60%25。