Two separate transhydrogenase activities are present in plant mitochondria
1999 (English)In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 265, no 1, 106-111 p.Article in journal (Refereed) Published
Inside-out submitochondrial particles from both potato tubers and pea leaves catalyze the transfer of hydride equivalents from NADPH to NAD(+) as monitored with a substrate-regenerating system. The NAD(+) analogue acetylpyridine adenine dinucleotide is also reduced by NADPH and incomplete inhibition by the complex I inhibitor diphenyleneiodonium (DPI) indicates that hive enzymes are involved in this reaction. Gel-filtration chromatography of solubilized mitochondrial membrane complexes confirms that the DPI-sensitive TH activity is due to NADH-ubiquinone oxidoreductase (EC 1,6,5,3, complex I), whereas the DPI-insensitive activity is due to a separate enzyme eluting around 220 kDa. The DPI-insensitive TH activity is specific for the 4B proton on NADH, whereas there is no indication of a 4A-specific activity characteristic of a mammalian-type energy-linked TH. The DPI-insensitive TH may be similar to the soluble type of transhydrogenase found in, e.g., Pseudomonas. The presence of non-energy-linked TR: activities directly coupling the matrix NAD(H) and NADP(H) pools will have important consequences for the regulation of NADP-linked processes in plant mitochondria. (C) 1999 Academic Press.
Place, publisher, year, edition, pages
1999. Vol. 265, no 1, 106-111 p.
IdentifiersURN: urn:nbn:se:umu:diva-44666DOI: 10.1006/bbrc.1999.1627ISI: 000083721200018OAI: oai:DiVA.org:umu-44666DiVA: diva2:433650