Effect of the external electric field on the formation of M-product in oriented bacteriorhodopsin films

The influence of the external electric field on the formation of M-product in the bacteriorhodopsin photocycle in oriented films of halobacteria purpl e membranes (PM) was studied. Electric field directed towards the external surface of PM was shown to stimulate the formation of M-product and inhibit its decay in the dark. Time constants of all three kinetic components rema ined unaltered. The electric field of opposite direction reduced the yield of M-photoproduct and increased the amplitude of the fastest component in t he M-product decay.