Role of Musa paradisiaca ascorbate peroxidase in the transformation of methyl phenyl sulfide to its sulfoxide.

An ascorbate peroxidase from a new source Musa paradisiaca leaf juice has been purified to homogeneity using a simple procedure involving concentration by ultra filtration and anion exchange chromatography on diethyl amino ethyl [DEAE] cellulose column. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis [SDS-PAGE] analysis of the purified enzyme has shown a single protein band of molecular mass 208.9 kDa which has been confirmed by native-PAGE and intact mass analysis by mass spectrometry. The Km and kcat values of the enzyme using ascorbate and H2O2 as the variable substrates were 0.13 m mol L-1, 40.42 s-1 and 0.23 m mol L-1, 27.24 s-1, respectively. The pH and temperature optima of the enzyme were 7.0 and 298 K, respectively. The enzyme transformed approximately 97% methyl phenyl sulfide to its sulfoxide. The product was racemic mixture.