Determination of CGTase activity

The determination of CGTase activity has been in a progressive state of exploration because the enzyme has four catalytic activities and it is difficult to put them together in the determination of normal activity. In CD production catalyzed by CGTase, four types of reactions, i.e., the cyclization, hydrolysis, coupling and disproportionation, take place simultaneously. Because there are several 

The activity calculated according to above formula includes both the enzyme activity of dextrin and the generation of activity. 

The HPLC method to determine the amount of CD generated is fast and accurate in determining the activity of CGTase. About 0.5 mL CGTase solution and 6% starch solution (Macllvaine Buffer 100 mmol/L, pH 6) 2.5 mL were incubated at 50°C for 60 min, boiled to inactivate the enzyme activity, and separated on NH2 or ODS column. There is a linear relationship between the resulting amounts of a-, P- and y-CDs (sample volume of 5 fig) and amoimt of fi-CD (mg) when CGTase concentration is below 10 x 10 imits. 

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