Picosecond flash photolysis of Halobacterium halobium bacteriorhodopsin at room and low temperatures

The primary stage of photoexcitation of bacteriorhodopsin from Halobacterium halobium upon the action of ultrashort (tau equal to 25 ps) laser impulse of 530 nm wavelength and of energy 2.5.10(-3) J has been studied. The primary photoproduct with a maximum of 630 nm is shown to occur in the differential spectrum in a time less than 25 ps both at room temperature (+20 degrees C) and at a low temperature (-150 degrees C).