Autoinhibition in (Bio)Chemistry: Identification and Mechanistic Classification.

Autoinhibition is a frequently invoked self-regulatory mechanism involved in various cellular processes to interpret clearly how these cells may control their complex functioning. This type of temporal behavior generally results in self-retardation or even in complete shuts down of the undesired reactions to occur meaning that the rate of a certain biochemical reaction is partially or completely retarded. Precise characterization and classification of a complex system where deceleration of the reaction rate is found, however, requires special circumspection to avoid false interpretation. Hereby, it was clearly demonstrated that the retardation effect of an inhibitor is unexpectedly often misidentified as autoinhibition, especially in complex biochemical enzymatic systems. It prompted us to clarify unambiguously the difference between inhibition and autoinhibition. The latter kinetic phenomenon is a special type of inhibition where the inhibitor forms by the result of a chemical or biochemical event exerting the self-decelerating effect on the rate of its own formation resulting thus in significantly different temporal patterns compared to the ones observed in the case of simple inhibitions. Kinetic activity of autoinhibitor towards the species involved in the given system allowed us to classify direct, indirect and dual autoinhibitions to be supported by real chemical examples.