Apparent molar volumes of some amino acids and peptides in aqueous urea solutions

Abstract

Abstract Densities of solutions of several α‐amino acids and peptides in 3 and 6 m aqueous urea solvents have been determined at 298.15 K. These data have been used to evaluate the infinite‐dilution apparent molar volumes of the solutes and the volume changes due to transfer ( V ) of the α‐amino acids and peptides at infinite dilution from water to aqueous urea solutions. The sign and magnitude of the V values have been rationalized in the framework of Friedman's cosphere‐overlap model. The V values for the glycyl group (CH 2 CONH) and alkyl side chains have been estimated.