Abstract Two new 35 S reagents were developed to radiolabel proteins. The first reagent, N- succinimidyl-4-(methane [35 S] sulfonylamino-methyl)-benzoate (SMSB), acylates the ε- amino group of lysine residues in proteins. The second reagent, 4-(methane [35 S] sulfonylamino-methyl)-phenylpropylaldehyde (MSAPPA), labels lysine residues via reductive alkylation. Comparing the two methods, the reductive alkylation method labeled ...
