Reaction-induced infrared difference spectroscopy for the study of protein function and reaction mechanisms

Infrared spectroscopic methods have been developed in the past decade to a sensitivity and selectivity which renders them useful for the study of enzyme function and enzyme reaction mechanisms. Originally developed as difference techniques for the investigation of light-induced reactions of photoreactive proteins, and matured in the field of bacteriorhodopsin and rhodopsin, they can now be used for the study of redox proteins by the use of electrochemical cells, or for the study of many different enzymes by the use of photolabile effector molecules. This brief review summarizes the currently available methods of infrared difference spectroscopy, the technical prerequisites, achievements and limitations.