We have studied the kinetics of the complex formation of gold(III) complexes, [AuCl(2)(en)](+) (dichlorido(ethylenediamine)aurate(III)-ion) and [AuCl(2)(SMC)] (dichlorido (S-methyl-l-cysteine)aurate(III)) with four biologically N-donor nucleophiles. It was shown that studied ligands have a high