Scheme 1.
The kinetic mechanism of the interaction between APE1 and DNA containing an abasic site. Е is the enzyme, S is a DNA substrate, (E·S)1 and (E·S)2 are complexes of the enzyme with the substrate, Р is a product of substrate conversion, E·P is a complex of the enzyme with the product, ki and k−i denote rate constants of direct and reverse reactions (i = 1 or 2) of reversible steps, k3 is a rate constant of the catalytic reaction, and Kp is the equilibrium dissociation constant for the Е·Р complex.