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 purple 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 remained unaltered. The electric field of opposite direction reduced the yield of M-photoproduct and increased the amplitude of the fastest component in the M-product decay.