Improving the Time Resolution for Remote Control of Enzyme Activity by a Nanosecond Laser-Induced pH Jump

Application of light as a trigger for remote control of enzyme activation offers high temporal and spatial resolution. A known enzymatic system based on an acid phosphatase and 6‐chloro‐8‐fluoro‐4‐methylumbelliferone phosphate as substrate is employed to study different strategies for improving the time resolution of enzyme activation by a light‐induced pH jump. Hence, a single laser pulse excitation with a pulse duration of 6 ns resulted in a 4‐fold enzyme activation by instantaneous proton release through the rearrangement of 2‐nitrobenzaldehyde. The time resolution of the activation experiment is now limited only by the detection system, no longer by the excitation step. In addition, halogenated 2‐nitrobenzaldehydes are tested for their suitability as phototriggers and a detailed study of the pH‐dependent kinetics of the enzymatic reaction is performed, which reveals that the substrate can probably only bind to the enzyme in its monoanionic form. Spotlight on: A laser‐induced enzyme activation method for application in real‐time analysis of proteinogenic systems is demonstrated on a nanosecond time scale. A pH jump is used for switching the activity of a hydrolytic enzyme. The time resolution of activation is thereby only limited to a few nanoseconds.