Watching Individual Enzymes at Work

Abstract

Single-molecule fluorescence experiments are a powerful tool to analyze reaction mechanisms of enzymes. Because of their unique
potential to detect heterogeneities in space and time, they have provided unprecedented insights into the nature and mechanisms
of conformational changes related to the catalytic reaction. The most important finding from experiments with single enzymes
is the generally observed phenomenon that the catalytic rate constants fluctuate over time (dynamic disorder). These fluctuations
originate from conformational changes occurring on time scales, which are similar to or slower than that of the catalytic
reaction. Here, we summarize experiments with enzymes that show dynamic disorder and introduce new experimental strategies
showing how single-molecule fluorescence experiments can be applied to address other open questions in medical and industrial
enzymology, such as enzyme inactivation processes, reactant transfer in cascade reactions, and the mechanisms of interfacial
catalysis.