Ultrafast catalytic processes in enzymes.

The study of biocatalysis and biotransformation in the transition-state region has been challenging and difficult, but recent advances on two important photoenzymes in nature, DNA photolyase and protochlorophyllide oxidoreductase, have enabled the investigation of their catalytic processes in real time. By following the entire evolution of substrate transformation, the functional dynamics constituting a series of elementary reactions have been mapped out. The five fundamental reactions in the enzymes, namely electron transfer, bond breaking and making, proton and hydride transfer, all occur ultrafast within subnanosecond. The direct clocking of catalytic transition states probes central, unmasked chemical processes and provides mechanistic insights into the role of the dynamics in enzyme function, which not only facilitates the formation of the enzyme-substrate complex in the transition-state configurations, but also modulates the subsequent catalytic reactions for maximum biotransformation efficiency.