Nonenzymatic formation of Chl d from Chl a with hydrogen peroxide

Abstract

Nonenzymatic conversion of Chl a to Chl d was performed for the first time by dilute hydrogen peroxide (H2O2) in aqueous acetone (acetone/dilute H2O2 = 10/1, v/v) at 303 K in the dark. The conversion was observed within five minutes incubation when 0.3% H2O2 was used. The Chl d production yield reached to the maximum, ca. 0.41%, at the incubation time of 5 min. The Chl a to Chl d conversion was also observed when 3% H2O2 and 0.03% H2O2 were used, but the maximum yields were much lower, 0.05% and 0.16%, respectively. The converted Chl d was then gradually degraded probably due to the strong oxidation power of H2O2. Our findings indicate that Chl d is apt to be produced as one of the degradation products of Chl a in nature.