Reaction of poly-L-lysine with aryl acetates and aryl methyl carbonates. A mechanistic study

The pH profile (log k vs. pH) of the reactions of poly-L-lysine (PL) with a series of aryl acetates and aryl methyl carbonates in aqueous solution show the same conformational changes as those determined by potentiometric titrations. When PL is a random coil, the most probable mechanism for the reactions studied is through the formation of a tetrahedral intermediate and its breakdown to products as the rate-determining step. The tetrahedral intermediate is stabilized by a hydrogen bond interaction between the nitro groups in the substrate and the NH group of the principal chain or some NH2 groups of the lateral chains. Copyright (C) 2007 John Wiley & Sons, Ltd.