Peroxidase in unripe and ripe star fruit (Oxalidacia Averrhoa) in different stages of maturation

Abstract

The soluble and ionically bound peroxidase (EC. 1.11.1.7) was extracted from the star fruit in different stages of maturation. The extracts were prepared using solution 100 mM sodium phosphate buffer at pH 7.0 and the enzymatic activity of those extracts was measured. The maturation degree did not influence the soluble peroxidase activity; however, some changes were observed in the activity for the ionic bound peroxidase. For the study of peroxidase thermal stability, the crude extracts were submitted to temperatures of 60, 65, 70, 75, 80 and 85°C and the enzymatic activity was carried out at intervals of 0, 2, 4, 6, 8 and 10 minutes. It was observed that the enzyme lost activity with increasing time and temperature. For purification, the concentrated extract of the soluble peroxidase was dialysed, using a solution of 10mM of the sodium phosphate buffer pH 7.0, after the sample was applied in a chromatographyc column (16 mm i.d x 70 cm) packed with Sephacryl HS100 with flow rate of 30 mL/h. The electrophoresis results showed the presence of an anionic isoenzyme with 64kDa MW.