Because to the redox properties, the Cu(II) coordination compounds have been used as potential antineoplastic agents. However these may have their bioavailability compromised by interaction with biological components, depending on their chemical structure. This fact motivates us to demonstrate the effect of ligand type on interaction of a BSA plasma protein with two coordination compounds [Cu(1,10-phenanthroline)₂(NO₃)]⁺ y [Cu(Bztpen)]²⁺, (Bztpen=N-benzyl-N,N’,N’-tris (pyridin-2-ylmethyl) ethylenediamine), by means of electrochemical and spectroscopics thechniques of circular dichroism.