SUPEROXIDE-DISMUTASE MIMETIC ACTIVITY OF A CYCLIC TETRAMERIC SCHIFF-BASE N-COORDINATED CU(II) COMPLEX

A pulse radiolytic study using the cyclic tetrameric Schiff base N-coo rdinated copper complex Cu(TAAB)(2+) has been performed, The reaction of the Cu(TAAB)(2+) complex with superoxide revealed pseudo first-orde r characteristics with the rate constant of k(2) = (2.9 +/- 0.5) x 10( 8) mol(-1) s(-1) dm(3), The complex survived the presence of competing serum albumin in physiological concentrations, The complex stability constant K = 1.15 x 10(18) (log K = 18.06) is two orders of magnitude higher than that of Cu(II)-serum albumin (log K = 16.2), Transient cha nges of the stability during the oxidation/reduction process and in th e presence of 600 mu mol l(-1) albumin did not affect significantly ei ther the electronic absorption of the complex or its catalytic activit y,