[Energizing of F1-ATPase after irradiation with visible light]. / Energizatsiia F1-ATFazy pri obluchenii vidimym svetom.

It was shown that ATP synthesis by F1-ATPase sensitized by visible light was combined with oxidation of SH groups and decrease of initial flavin fluorescence in the F1-ATPase preparation. It was suggested that it was an endogenous flavin group that regulated redox transitions between SH-S-S groups which was essential for the catalysis in vivo.

[Effect of visible light on the ATP synthetase function of mitochondria]. / Vliianie vidimogo sveta na ATF-sintetaznuiu funktsiiu mitokhondrii.

Dependence of oxidative phosphorylation in rat liver mitochondria on redox state of endogenous flavoenzymes was studied. Regulation of the redox state of endogenous flavins in mitochondria was performed by visible light illumination of lambda = 380 nm in oxygen free as well as in oxygenated media. A decrease of oxidative phosphorylation was obtained at full reduction of flavins (respiratory control and ATP synthesis were measured); this effect was partially recovered when flavin was reoxidized by oxygen. Results of ESR measurements of the signal gl = 2.00 associated with semireduced flavins were in accordance with the appearance of diamagnetically completely reduced form of flavin. These facts may be considered as evidence of the regulative role of flavins in oxidative phosphorylation.

[Electron spin resonance of phosphorylating and non-phosphorylating submitochondrial particles]. / Elektronnyi paramagnitnyi rezonans fosforiliruiushchikh i nefosforiliruiushchikh submitokhondrial'nykh chastits.

Paramagnetic centres related with the work of ATP-synthetase, found earlier on mitochondria were studied on phosphorylating and non-phosphorylating submitochondrial particles (SMP). A complex doublet signal with half-width 38 . 10(-4) T was shown to be recorded only on actively phosphorylating and oligomycin-inhibited SMP. It was found that the signal components were conditioned by different paramagnetic centres, one of which (g = 2.03) seemed to be the metal centre, more probable non-hemeiron. The nature of the second signal characterized by evenly saturating doublet components with g = 2.03 and g = 2.00 is unclear. Studies of flavin signal saturation have also shown that it consists of two components: one of them--saturating, specific for non-phosphorylating SMP, another--non-saturating, mostly observed in phosphorylating SMP, probably conditioned by flavin--the constituent of ATP-synthetase.