This commercially available peptide/protein-modifying reagent (FW = 134.13 g/mol; CAS 1074-12-0), occasionally called benzoylformaldehyde, is a mild oxidant that reacts covalently with guanidinium groups at pH ~ 7, consuming two moles of reagent per mole of reactive arginyl residue. Modified guanidinium groups are relatively stable below pH 4; however, the original guanidinium group is slowly regenerated at neutral or alkaline pH. Upon prolonged incubation with phenylglyoxal, a-amino groups may also be modified. See also Glyoxal; 4-Hydroxyphenylglyoxal; etc. Target(s): To date, over 240 enzymes are inhibited by phenylglyoxal
