Modulation of the Access of Exogenous NAD(P)H to the Alternative Pathway in Potato Tuber Callus Mitochondria with Triton X-100.
Alternative oxidase activity in potato tuber (Solanum tuberosum L. cv Bintje) callus mitochondria with exogenous NAD(P)H as substrate is inhibited by low concentrations of the detergent Triton X-100. Alternative oxidase activity with succinate or malate as substrate is not affected by these low concentrations of Triton X-100. Cytochrome pathway activity was not influenced under these conditions, neither with endogenous nor with exogenous substrate. Washing of Triton X-100-treated mitochondria did partially restore both uninhibited and CN-resistant NADH oxidation, indicating that under these conditions Triton X-100 does not permanently remove major components from the mitochondrial membrane. Apparently, it is possible to manipulate mitochondria in such a way that the access of exogenous NADH to the alternative pathway is blocked while access to the cytochrome pathway is uninhibited. It is suggested that membrane conditions have a regulatory function (possibly via influencing the diffusion path) in the oxidation of exogenous NADH via the alternative pathway.
Wagner
A M
AM
Department of Physiology and Biochemistry of Plants, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands.
van den Bergen
C W
CW
Krab
K
K