Process Biochemistry, Vol.66, 97-105, 2018
Peroxidase characterization isolated from germinated peanut embryos (GPE) and application of the freeze-dried GPE powder as enzyme source for biomimetic production of delta-viniferin
Novel enzyme source is essential in biomimetic synthesis. Use of peanut peroxidase in mediation of oxidative polymerization of phenolic compounds is meager. In this study, the 5 day-germinated peanut embryos were homogenized, centrifuged to collect supernatant and (NH4)(2)SO4 fractionated, the 40-75% saturated fraction exhibited most peroxidase activities. After UF-concentration between MWCO 300 and 10 kDa, Sephacryl 5300 gel filtration and DEAE-Sephadex A25 ion-exchange, a 50.6-fold-purified peroxidase with 32 kDa in SDS-PAGE analysis was obtained. The freeze-dried and pulverized into powder (GPEP) bearing potent peroxidase activities was used in biomimetic resveratrol dimerization. In a semi-continuous system mediated by 0.5 g GPEP suspended in phosphate buffer (pH 7.4) with continuous feedings of resveratrol dissolved in acetone and aqueous H2O2 solution for 150 min, all added resveratrol reacted. After subjecting the reactant to SPE C18 cartridge clean-up, semi-HPLC purification and NMR 1- and 2D spectroscopic elucidation, a dimeric product was identified as delta-viniferin with ca. 60% of recovery. The delta-viniferin exhibited potent trolox equivalent antioxidant capacity as did BHT. It is of merit to demonstrate GPEP as a potential peroxidase source enabling scalable biomimetic production of delta-viniferin.
Keywords:Peroxidase;Peanut embryo;Biomimetic synthesis;Resveratrol;1-and 2D NMR;delta-viniferin;Oxidative coupling dimerization