title: Characteristics of rotenone-insensitive oxidation of matrix-NADH by broad bean mitochondria.
abstract: Mitochondria from Vicia faba L. exhibit two pathways for the oxidation of endogenous NADH. One pathway is rotenone-sensitive and includes three phosphorylation sites, the other one is rotenone-insensitive and by-passes site I. This by-pass is located in the area of flavoproteins, but several lines of evidence suggest that the rotenone-insensitive oxidation of matrix-NADH is not mediated by the external NADH dehydrogenase. With saturating substrate concentrations the two pathways are superimposed in state 3 while in state 4 the electrons are transferred only via the by-pass. The rotenone-resistant electron flux is obviously regulated from the substrate side. We suggest that the function of the by-pass is to regulate the NADH/NAD(+) ratio of the matrix space.
authors.affiliation: Botanisches Institut der Universität, Kirschallee 1, D-5300, Bonn 1, Federal Republic of Germany.
authors.forename: R
authors.initials: R
authors.lastname: Marx
authors.forename: K
authors.initials: K
authors.lastname: Brinkmann