Comparative Studies on Hemin as a Mimic of Peroxidase with Horseradish Peroxidase

The reaction kinetics and spectral characteristics of products of the hemin catalyzed oxidation of p hydroxyphenylpropionic acid with hydrogen peroxide were studied through fluorometry and spectrophotometry. Hemin was found to show peroxidase like, catalase like activities, and to be decomposed due to oxidation and dimerization. Besides the primary product with maximum emission at 406 nm when excited at 320 nm, the system has a fluorescent by product with an emission peak at 360 nm when excited at 258 or 300 nm. The difference in specificity of hemin and horseradish peroxidase was examined by comparing spectral characteristics of reaction product. The competitive relationship of the multiple roles of hemin in the system was discussed. The result is of importance in mimicry of peroxidase with high specificity.