Effects of high pressure on enzymatic activity.

Effects of high pressure on enzymatic reactions are poised to revolutionize enzyme kinetics. The reason for this is that experimental designs are at hand to separate effects on equilibria between reactant states from effects on catalytic transition states and both yield new information. The first of the former runs contrary to Pauling's hypothesis that substrates are bound more tightly in the transition state, while the latter penetrates the 'black box' of catalysis, the stabilized transition state itself, and returns a precise measure of a physical parameter, deltaV. This in turn opens the door to new forms of structure-activity relationships. The first of these has been described, the effect of pressure on isotope effects, with the surprising finding that the entire isotope effect comes from a transition state phenomenon such as quantum mechanical hydrogen tunneling.