Ways to monitor enzyme kinetics with very fast time resolution? I'm interested in any way to do time-resolved study of enzyme kinetics. I am studying some physical variables that may affect kinetics, but I want to study how quickly they take effect, and how long the effect lasts. The time scale of interest is milliseconds or less, so the typical spectrophotometric methods (which usually look at absorption change over fairly long times on the order of minutes) won't work. Luciferase activity can be monitored by tracking the light emitted, and this has potentially very high time resolution as the time between reaction and light emission is on the order of microseconds. However luciferase is a bit of an odd model, as it is not part of normal metabolism or signalling in most organisms. Is there a way to track enzyme kinetics of any other enzymes with a similarly fast time resolution? **EDIT** Just discovered one name for what I'm looking for: "transient kinetics".

Some ATPases can work with MANT-ATP or similar fluorescent ATP analogs that change their fluorescence properties upon protein binding as well as hydrolysis of their phosphate group. This has been used frequently (see here or here) to study enzyme kinetics on fast timescales.