Barrier compression enhances an enzymatic hydrogen-transfer reaction.

Putting the squeeze on: Hydrostatic pressure causes a shortening of the charge-transfer bond in the binary complex of morphinone reductase and NADH(4) (see diagram). Molecular dynamics simulations suggest that pressure reduces the average reaction barrier width by restricting the conformational space available to the flavin mononucleotide and NADH within the active site. The apparent rate of catalysis increases with pressure.