Kinetics of hog pancreas alpha-amylase; theoretical model of the dual-site enzyme.

The model of the multiple attack mechanism has been proposed for the enzyme consisting of two hypothetical subunits or domains identical in structure and function. The theoretical coefficients of multiple attack: effectiveness and average number of unitary movements, have been computed for such a dual-site model of pancreatic alpha-amylase. Those coefficients affect the values of maximum velocity and Michaelis constant, respectively. Two possible manners of the subunit coupling were considered: symmetric and sequential. The dual-site model with a symmetric type of coupling appeared to be kinetically indistinguishable from the single-site model.