POLYMERS WITH AMINO-ACIDS IN THEIR SIDE-CHAIN - CONFORMATION OF POLY(N-METHACRYLOYL-L-METHIONINE)

A homopolymer bearing L-Methionine (PMet) in its side chain was synthe sized by free radical polymerization of the corresponding vinyl monome r. Viscosimetric and pHmetric measurements indicate that PMet, in wate r at low pH, takes a compact conformation, which is destroyed (expande d) with increasing ionization of the carboxyl groups of the side chain s. The influence of temperature and of some additives (neutral salt, u rea, organic solvent, SDS) on the compact conformation and the pH-indu ced conformational transition was investigated. It was concluded that hydrogen bonds are the main factors responsible for the existence of t he compact conformation. (C) 1995 John Wiley and Sons, Inc.