[Interaction of flavin adenine dinucleotide and tryptophan NADPH-adrenodoxin reductase complexed with adrenodoxin].

The NADPH-adrenodoxin complex with adrenodoxin is responsible for the transformation of the two-electron flow from NADH to the mono-electron flow to cytochrome P-450 in the steroid-hydroxyl enzyme system of mitochondria of kidney crust. Depolarization of emission of the reductase prosthetic group FAD with the maximum at 525 nm excited at the wave length approximately 290 nm in comparison with the excited at 450 nm provides an evidence of presence of the Ferster energy excitement transfer to FAD from the group absorbed at 290 nm. This fact and the form of absorbance spectra of the complex of two peptide points to the fact that the complex formation is accompanied by interaction of FAD with the residue of tryptophan in the reductase. Based on these facts and the data concerning participation of tryptophan and tyrosine of adrenodoxin in the electron transfer between the hypothesis is suggested about the intracomplex path of the electron that can explain the mechanism of switching of the two-electron transfer into the mono-electron one.