Complexation of copper(II) with L-alanine and its N-alkyl derivatives

A series of mono- and di- alkylated L-alaninates, as well as their copper(l l) complexes, were prepared as model compounds for superoxidedismutase (SOD )-mimetic activity. Two independent methods (glass electrode potentiometry, GEP and square wave voltammetry, SWV) were applied in order to determine t heir concentration stability constants and speciation under the physiologic al conditions (mu = 0.15 M). The chelates formed by copper(ll) and mono- an d di-alkylated L-alaninates are less stable (by factor >10) than the parent copper(ll) L-alaninates. From a thorough examination of the data obtained, a conclusion may be drawn that further lengthening the alkyl chain (diethy l- and more) on nitrogen atom of L-alanine will not essentially change the values of the stability constants of copper(ll) complexes with N-alkylated L-alaninates which was confirmed by the conformational analyses performed o n the same compounds.