The Peroxidase of Dioscorea esculenta: Partial Purification and Characterisation

Z. Naturforsch. 54c, 496-500 (1999); received January 11/March 27. 1999 Dioscorea esculenta. Peroxidase. Ion Exchange C hrom atography. Gel Filtration We isolated two types of peroxidase from the fresh tuber of Dioscorea esculenta using a com bination of ion exchange and gel filtration chrom atography. The results showed one type to be neutral and the other to be strongly ionic. The strongly ionic type constitutes 70% of total peroxidase activity in the tissue. The apparen t m olecular weight of the neutral type is 38 kD a while the anionic type has an apparen t m olecular weight of 57 kD a. It was possible with the use of gel filtration on Sephadex G-200 followed by FPLC on phenyl superose to purify the lower size POD by a factor of 15, while the larger ionic peroxidase was purified 68 fold com pared to the crude with protein yields of 0.90% and 1.30% respectively. The ionic PO D is more therm o-stable, has a higher optim um tem perature for activity and has a higher apparent activation energy com pared to the neutral PO D from this source.