Regioselective Modification of Lysine's Amino Groups by Proteases

Abstract

The regioselectivity of six serine proteases for the amino groups of lysine was investigated. α-Chymotrypsin showed a preference for the α-amino group, although the selectivity can be varied 10-fold depending on the reaction medium. Subtilisin Carlsberg and other bacterial proteases were highly specific for the ε-amino group, regardless of the reaction medium: they were used as catalysts for the preparative synthesis of isopeptides in anhydrous tert-amyl alcohol.