ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 33, Number 4
JKCSEZ 33(4)
August 20, 1989 

The dissociation constants of β-alanine and γ-aminobutyric acid were measured in the temperature range from 20 to 40℃ and pressure up to 2,500 bar by conductometric method. The both dissociation constants of respective amino acid increase with temperature increase but pressure effect is not same as the temperature. The K1 increases as pressure increases but K2 decreases. The properties of these amino acids were discussed in terms of the thermodynamic properties of the dissociation reaction. A relationship between the dissociation constants and the distance between substituted groups of amino acid was discussed. The substituted effects of the reaction were deduced from Hammett reaction and substituted constants which were calculated from the measured dissociation constants.