[Characteristics of the respiratory chain and the oxidative phosphorylation system of mitochondria in the flavinogenic Eremothecium ashbyii strain].

Tightly coupled mitochondria were isolated from cells of the flavinogenic strain of Eremothecium ashbyii collected during the logarithmic and stationary growth phases. The composition of the respiratory chain and characteristics of the energy coupling system are described. The mitochondria show a wide spectrum of metabolic activity and oxidize Krebs cycle compenents and exogenous NADH. The terminal segment of the respiratory chain is represented by a typical cytochrome system. The mitochondria of the ascomycete collected during the logarithmic growth phase are characterized by a relatively high content of cytochromes b and c, a high rate of oxidation of NAD-dependent substrates, the presence of lower homologues of ubiquinone, UQ6 and UQ7, and extremely high sensitivity of respiration to the action of antimycin A, low content of a component sensitive to rotenone, contrasting with the operation of all three sites of phosphorylation. Transition to the stationary growth phase is accompanied with a decrease in the rate of oxidation of all substrates studied and a declined effectiveness of oxidative phosphorylation. The data obtained are discussed in relation to the ability of the cells for "overproduction" of flavins.