Purification and physicochemical studies of estrase enzyme from potato tuber by gel filtration and polyacrylamide gel electrophoresis

ABSTRACT

The major esterase enzyme of potato tuber cultivar 'ALPHA' with molecular weight of 85 K Da was separated by a new method. A successful scheme using column chromatography with cephacryl S-300 and Sephadex G-75 were used. The physical mid chemical properties of the separated esterase enzyme was studied after Its separation on polyacrylamide electrophoresis. The results reported that it consists of a dimer of heterogenous charge with homogenous molecular weight [80 K Da] and the subunits are not disulfide bonded. The major soluble glycoprotein fraction from potato tubers has been isolated by racusen and Foote [1980] using chromatography on DEAE cellulose and Con A .cepharose and were given the trivial name 'Patatin' 'Patois' is the same as a family of potato tuber glycoprotein isolated by HPLC and solubility fractionations and were given the name "Tuberin [Kosier and Desborough, 1981]. These protein are significant not only because they we most abundant in the tuber protein but also because of their excellent nutritional value. A successful scheme consist of sequential treatment of potato juice with Sephacry S-300 and sephadex G-75 which yielded a single protein referred to as esterase enzyme and represented 40% of total soluble protein in the mature tuber [Park 1983; Racusen 1983; Park et al, 1983]. The physical and chemical properties of the eaterase enzyme was studied by electrophoretic methods: