Polyphenol oxidase is a generic name for a group of enzymes capable of catalyzing reactions for several phenols to produce o-quinones and it is responsible for the darkening of cut surfaces of fruits, vegetables and plants. Polyphenoloxidase was extracted and partially purified from two sub-species of Cola nitida, alba (white cola) and rubra (red cola) using ammonium sulphate precipitation. The effect of pH and temperature on the activity of enzyme was investigated while the thermal stability, pH stability and the kinetic parameter were determined. The optimal pH and temperature activity of polyphenoloxidase from both samples were found to be pH9.0 and 50oC. The enzyme was very stable at pH 4-6 for 2hours in the two cola while also maintaining 100% stability at 30 – 40oC for 1 hour. About 60% and 45%, 55% and 30%, 40% and 25% residual activity were observed for white (alba) and red (rubra) respectively at 50oC, 60oC and 70oC after 10minutes inubation time. The Michealis-Menten constant, Km for Cola nitida subspp. alba and rubra were 2.33mM and 5.63mM respectively while Vmax were 77unit/min/ml and 70unit/min/ml respectively. The enzyme showed activity toward both monophenol and diphenol substrate but with a higher activity for monophenol
PAPER TITLE :COMPARATIVE PHYSICOCHEMICAL PROPERTIES OF POLYPHENOLOXIDASE FROM WHITE AND RED KOLANUTS (COLA NITIDA
JOURNAL Of SUSTAINABLE TECHNOLOGY | VOLUME 3 NUMBER 1 2012
Paper Details
- Author(s) : SANNI, D.M. and ADEKUNLE, A.A
- Abstract:
