Actinic light density dependence of the O intermediate of the photocycle of bacteriorhodopsin.
The O intermediate of the photocycle of bacteriorhodopsin (BR) was studied by absorption kinetic measurements at different actinic light densities. With increasing exciting flash intensity, the relative yield of O slightly increases, while that of Mf strongly decreases at the expense of Ms. Kinetic calculations and the optical anisotropy of O show that O can be formed only from Mf although Mf and O have different light intensity dependences. In order to resolve the apparent contradiction, a phenomenologically new cooperative regulatory mechanism seems to be necessary.
Luchian
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T
Faculty of Physics, Al. I. Cuza University, Iasy, Romania.
Tokaji
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Dancsházy
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D000042:Absorption; D001436:Bacteriorhodopsins / Q000502:physiology* / Q000528:radiation effects; D007700:Kinetics; D008027:Light; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*; D010777:Photochemistry; D013997:Time Factors
D001436:Bacteriorhodopsins; D010100:Oxygen