METHEMALBUMIN AS BIOCATALYST OF OXIDATION OF AROMATIC-AMINES BY HYDROGEN-PEROXIDE

The kinetics of hydrogen peroxide-dependent oxidation of 3,3',5,5'-tet ramethylbenzidine (TMB) and o-phenylenediamine (PDA) catalyzed by hemi n and its complex with bovine serum albumin (BSA) was studied. Complex formation of hemin with BSA increased catalytic activity with hemin i n oxidation of both amines. The reaction follows first order kinetics in concentration of biocatalyst, H2O2, and H+ in a range of pH from 6. 5 to 9.0. Catalytic and Michaelis constants were calculated from doubl e reciprocal plots of the initial rates of TMB and PDA oxidations vers us their concentration catalyzed by hemin and methemalbumin. The mecha nism of the radical oxidation of amines in the presence of hemin-H2O2 or hemin-BSA-H2O2 is discussed. Both systems can generate free radical s and their effectiveness is comparable to the previously studied ferr itin-H2O2 system.