The kinetics of enzyme cascade systems: General kinetics of enzyme cascades

The theory of the kinetics of enzyme cascades is developed. Two types of cascades are recognized, one in which the products are stable ( open cascades ) and another in which the products are broken down ( damped cascades ). It is shown that it is a characteristic of a cascade that the final product appears after a certain lag phase. After this lag phase, the velocity of product formation can be very rapid. It is shown that whereas open cascades will always show a complicated time–product relation, damped cascades can under certain circumstances resemble a simple enzymic reaction. Because the relation between the over-all reaction velocity in the extrinsic coagulation cascade and the concentration of any of the proenzymes in this cascade is a hyperbolic one, it is concluded that this cascade is of the damped type rather than the open type.