title: Energetics and chronology of phototransients in the light response of the purple membrane of Halobacterium halobium.
abstract: Arrhenius parameters for formation and decay of phototransients in suspensions of purple membrane fragments in H2O and 2H2O have been determined in the temperature range 0-60 degree C. Kinetic isotope effects are found which show that proton transfer steps are involved in both formation and decay of the two longest-lived transients absorbing at 410 nm and 660 nm, respectively. The results also suggest that these transients do not occupy a single pathway in the spontaneous deexcitation of bacteriorhodopsin within the purple membrane. Purple membrane undergoes a phase transition at 25-30 degrees C in both H2O and 2H2O.
mesh_terms: D001436:Bacteriorhodopsins / Q000378:metabolism*; D002151:Calorimetry; D002338:Carotenoids / Q000378:metabolism*; D004735:Energy Transfer; D006217:Halobacterium / Q000378:metabolism*; D007700:Kinetics; D013696:Temperature; D013816:Thermodynamics
chemical_list: D002338:Carotenoids; D001436:Bacteriorhodopsins