[Possible mechanism of cooperative control in polyenzyme systems]

A mathematical model of an anabolic multienzyme system and its function mechanism is considered. The first substrate in this kind of biochemical system may be binded to its active site, provided the last product was released out of the system. The functional control is assumed to be exercised by cooperative rearrangement of the protein structure. Any intermediate or product molecule if present within the system, induces conformational changes in the entrance center of the multienzyme system, preventing the initial substrate binding. The steady-state product synthesis rate in such a system is determined by joint influence of rate constants at all stages of the reaction chain. The model corresponds closely to the multienzyme system of chlorophyll biosynthesis in higher plants. Essential advantages of cooperative controlled multienzyme systems in regulation of biochemical processes are discussed.