Volumes and heat capacities of some amino acids in water at 25 °C

Abstract

The apparent molal volumes and heat capacities of nine amino acids were measured in water at 25 °C with a flow densimeter and a flow microcalorimeter. It is shown that the poor additivity of the standard partial molal quantities of amino acids in water are attributable to the ionization of the two groups NH 2 and COOH. The hydration of these ionic groups interfere with each other when they are separated by less than three carbon atoms.