ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 31, Number 5
JKCSEZ 31(5)
October 20, 1987 

The two dissociation constants of three amino acid, glycine, alanine, and tryptophan were measured by the conductometric method in the temperature from 15 to 35℃ and pressure up to 2,500bar in aqueous solution. The both dissociation constants were increased as the temperature increased but the pressure effect were not same as the temperature effect. The first constants were increased as the pressure increased but second constants were decreased except tryptophan. The characteristic properties of these amino acids were discussed from the thermodynamic properties of the dissociation reaction. The substituted effects of the reaction were deduced from Hammett reaction and substituted constants which were calculated from the dissociation constants.