NADH Oxidation by Mitochondria from the Thermogenic Plant Arum orientale

Yu. V. Bertsova¹, V. N. Popov², and A. V. Bogachev^1*

¹Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119899, Russia; fax: (7-095) 939-0338; E-mail: sodiumc@genebee.msu.su

²Department of Plant Physiology and Biochemistry, Voronezh State University, Voronezh 394693, Russia; fax: (0732) 20-8755; E-mail: pvn@main.vsu.ru

^* To whom correspondence should be addressed.

Received November 24, 2003; Revision received December 18, 2003

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The enzyme content of the mitochondrial respiratory chain was investigated in the heat-producing plant Arum orientale. It is shown that mitochondria isolated from thermogenic tissues of this plant (with respect to non-thermogenic tissues of A. orientale or to Zea mays) demonstrate significantly elevated levels of activities of two non-coupled NADH dehydrogenases oxidizing intramitochondrial and cytoplasmic NADH pools. It is postulated that operation of a completely non-coupled respiratory chain consisting of non-coupled NADH:quinone oxidoreductases and cyanide-resistant alternative quinol-oxidase is the main mechanism of heat production in thermogenic plants.

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KEY WORDS: thermogenic plants, Arum orientale, NADH dehydrogenase, alternative oxidase, Complex I

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