metal-ion-coordinating properties of various amino acids, investigation of the essential function in biological systems regarding to their nano-structure

the acidity constants of some amino acids (am) were determined by potentiometric ph titration. the stability constants of the 1:1 complexes formed between m2+: ca2+, mg2+, mn2+, co2+, ni2+, cu2+ or zn2+ and am2-, were determined by potentiometric ph titration in aqueous solution (i = 0.1 m, nano3, 25°c). the order of the stability constants was reported. it is shown that the stability of the binary m(am) complexes is solely determined by the basicity of the carboxyl or amino group. all the stability constants reported in this work show the usual trend. the obtained order is ca2+