enzymatic reaction deamidation reaction 2017-08-08T14:38:29Z MI:2280 PSI-MI Reaction in which an amide functional group in the side chain of the amino acids asparagine or glutamine is removed or converted to another functional group. Typically, asparagine is converted to aspartic acid or isoaspartic acid and glutamine is converted to glutamic acid or pyroglutamic acid (5-oxoproline). deamidation ppm