Michaelis-Menten Behaviour and Dynamic Disorder in an Engineered Enzyme

Seminar series
Physical Chemistry Seminar
Mon, Feb 3 4:00pm
2033 Young Hall
Speaker Professor David Bensimon
University of California, Los Angeles
Dept. of Chemistry and Biochemistry

Abstract: In the past 10 years single molecule experiments studying the dynamic behavior of single enzymes have shown that in contrast with the often taught Michaelis Menten kinetics, the distribution of enzymatic cycle times did not exhibit simple exponential decay at long times. Rather it was characterized by stretched exponential decay which nonetheless and surprisingly displayed on average Michaelis Menten behavior. This behavior was attributed to the existence of many enzymatic conformers with different kinetic parameters. To explore this scenario we have designed and studied at the single molecule level a DNA template reaction that can display either simple exponential behavior (single conformer) at long time or multiple exponential decay (multiple conformers) while nonetheless displaying Michaelis Menten kinetics.  DNA template reactions thus appear as a nice testing bed for models of enzymatic behavior.