Abstract:

This paper aimed to study the biochemical characteristics of two hexokinase (HXK) isozymes-HXK1 and HXK2 which derived from Cabernet Sauvignon fruits. Crude enzyme, which obtained from former experiment, was treated with different substrates, and the activity of hexokinase was characterized by changes of absorbance 340 nm. The pI of the enzyme was determined by biuret method. The results showed that the ascending Km values of different hexoses were fructose, mannose and glucose, which proved that glucose was the optimal substrate. The maximum reaction rate of both isozymes appeared in fructose reaction. The pI of HXK1 and HXK2 was 5.8 and 5.6, and the optimum pH of two isozymes was about 8.0. It was concluded that the biochemical properties of HXK1 and HXK2 corresponded with the characterization of HXK.