[Inhibition of bacteriorhodopsin by formalin and lanthanum]

It was shown that the penetrating ions (PCB-) method can be used for quantitative estimation of the proton translocation function. Using this method it was found that the maximal inhibition (up to 5.5-6 times) can be achieved by 1% formalin treatment for 0.5 hrs in 0.5 M phosphate buffer, pH 7.8, 70 degrees. Using three methods, the kinetics of the obtained preparation were compared to those of the previously known inhibitor, La3+. The changes observed were as follows: inhibition of intermediate M412 decay in membrane suspension, decrease in the amplitude of the electric response millisecond phase in the purple membrane--collodium film system and deceleration of the overall photochemical cycle turnover in this system. The latter was registered by the rate of resporation of the electric response amplitude to the second light flash in the presence of uncoupling agents. The possible role of crosslinks during protein treatment with formalin is discussed.