Chloroperoxidase from the fungus Caldariomyces fumago is a versatile heme-peroxidase, which is able to catalyze olefin epoxidation. In this report, the epoxidation of m-substituted styrene catalyzed by chloroperoxidase was studied. The catalytic data fit the Hill's model, and the activity rate (kcat) constants were strongly dependent of nature of substituents. The epoxidation kcat values varied as follows: m-aminostyrene > styrene > m-methylstyrene > m-chlorostyrene > m-nitrostyrene. The catalytic rate constant for m-aminostyrene, an electron-releasing substituent, was 298 times higher than these for m-nitrostyrene, an electron-withdrawing compound. These results were quantitatively analyzed and a good linear correlation between the experimental catalytic constants of m-substituted styrenes and their ionization energies, calculated at B3LYP level of theory, was demonstrated.
- Ionization energies
- m-Substituted styrene
ASJC Scopus subject areas
- Process Chemistry and Technology