Conformational cycle of a single working enzyme

By simultaneous analysis of the on-time distribution and autocorrelation fu nction of a single working cholesterol oxidase enzyme, a diffusional model reveals the coupling of conformation change with enzyme action. Active-site oxidation induces a conformational change that opens the path for substrat e entry. Its binding, in turn, induces the reverse protein relaxation proce ss, which tightens the active site, thereby reducing the rate of product re lease.