Abstract
From the measurement of electric conductivity, binding of metal ion and aspartic acid was considered by the use of magnesium and potassium aspartate. This binding ability differs according to the equivalence ratio, R, between the metal ion and asparticacid, and the relationship between the equivalent conductivity and ionic strength of salt solutions with R=1 follows the Fuoss-Onsager and Robinson-Stokes formulae, indicating that such salts are strong electrolytes. In the case of magnesium salts, conductivity falls inversely when R becomes larger than 1, indicating that a conjugated compound has been formed. From the values of pH measured at the same time as the electric conductivity, the conjugated compound was assumed to exist in three types with the charge positive, negative, and zero. The same examinations were also made with barium, strontium, and calcium salts of aspartic acid and the ability of these metals to form the conjugates was found to decrease in the order of magnesium, calcium, strontium, and barium.
