[Acid-base equilibrium of D-(--)-alpha-aminophenylacetic acid].

Potentiometric titration was performed and the ioniziation macroconstants of D-(--)-alpha-aminophenylacetic acid and its methyl ether were determined. The constants were used for estimation of 4 microconstants of D-(--)-alpha-aminophenylacetic acid and the constants of the tautomeric equilibrium of the zwitter-ionic and neutral forms of the amino acid. Minimum solubility of D-(--)-alpha-aminophenylacetic acid was determined and pH-dependence of its solubility was estimated.