Abstract
Potato tuber mitochondria oxidized exogenous NADH and exogenous NADPH at similar rates; the electron transfer inhibitor rotenone did not inhibit the oxidation of either substrate. Submitochondrial particles, prepared from potato tuber mitochondria, exhibited a greater capacity to oxidize NADH than NADPH; rotenone inhibited the oxidation of NADH by 29% and the oxidation of NADPH by 16%. The oxidation of both NADH and NADPH by potato mitochondria exhibited pH optima of 6.8, and although substantial NADH oxidase activity was observed at pH 8.0, little NADPH oxidase activity was detected at that pH. The oxidation of NADPH by the mitochondria was more sensitive to inhibition by EDTA than was the oxidation of NADH.
The sulfhydryl reagents N-ethylmaleimide, p-chloromercuribenzoate, p-chloromercuriphenyl sulfonic acid, and mersalyl inhibited the oxidation of exogenous NADPH by the mitochondria whereas NADH oxidation was unaffected at similar concentrations of inhibitor. The data suggest that exogenous NADPH is oxidized by potato mitochondria via a dehydrogenase primarily situated on the outer face of the inner mitochondrial membrane that is neither the dehydrogenase involved with endogenous NADH oxidation nor with exogenous NADH oxidation.
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- Arron G. P., Spalding M. H., Edwards G. E. Isolation and Oxidative Properties of Intact Mitochondria from the Leaves of Sedum praealtum: A Crassulacean Acid Metabolism Plant. Plant Physiol. 1979 Aug;64(2):182–186. doi: 10.1104/pp.64.2.182. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coleman J. O.D., Palmer J. M. Role of Ca(2+) in the oxidation of exogenous NADH by plant mitochondria. FEBS Lett. 1971 Oct 1;17(2):203–208. doi: 10.1016/0014-5793(71)80148-5. [DOI] [PubMed] [Google Scholar]
- Coleman J. O., Palmer J. M. The oxidation of malate by isolated plant mitochondria. Eur J Biochem. 1972 Apr 24;26(4):499–509. doi: 10.1111/j.1432-1033.1972.tb01792.x. [DOI] [PubMed] [Google Scholar]
- Day D. A., Wiskich J. T. Isolation and properties of the outer membrane of plant mitochondria. Arch Biochem Biophys. 1975 Nov;171(1):117–123. doi: 10.1016/0003-9861(75)90014-4. [DOI] [PubMed] [Google Scholar]
- Earnshaw M. J. The mechanism of K+-stimulated exogenous NADH oxidation in plant mitochondria. FEBS Lett. 1975 Nov 1;59(1):109–112. doi: 10.1016/0014-5793(75)80352-8. [DOI] [PubMed] [Google Scholar]
- Hackett D. P. Pathways of Oxidation in Cell-free Potato Fractions. II. Properties of the Soluble Pyridine Nucleotide Oxidase System. Plant Physiol. 1958 Jan;33(1):8–13. doi: 10.1104/pp.33.1.8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanson J. B., Bertagnolli B. L., Shepherd W. D. Phosphate-induced Stimulation of Acceptorless Respiration in Corn Mitochondria. Plant Physiol. 1972 Sep;50(3):347–354. doi: 10.1104/pp.50.3.347. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koeppe D. E., Miller R. J. Oxidation of reduced nicotinamide adenine dinucleotide phosphate by isolated corn mitochondria. Plant Physiol. 1972 Mar;49(3):353–357. doi: 10.1104/pp.49.3.353. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Laties G. G. The potentiating effect of adenosine diphosphate in the uncoupling of oxidative phosphorylation in potato mitochondria. Biochemistry. 1973 Aug 14;12(17):3350–3355. doi: 10.1021/bi00741a032. [DOI] [PubMed] [Google Scholar]
- Strittmatter P. Protein and coenzyme interactions in the NADH-cytochrome b5 reductase system. Fed Proc. 1965 Sep-Oct;24(5):1156–1163. [PubMed] [Google Scholar]