A Low-Molecular-Weight ATPase from Wheat-Seedling Mitochondria

Abstract

An ATPase which strikingly differed from the mitochondrial ATPases of yeast and of animal tissues [heart muscle A and liver tissue] was obtained when wheat [Triticum aestivum] seedling mitochondria or electron transport particles derived from them were subjected to ultrasonication and treated with ammonium sulfate. The enzyme which was purified by chromatography on Sephadex G-100 and DEAE-Sephadex (A50) failed to be inactivated by keeping in the cold. The MW was shown by gel filtration to be as low as 43,000. The enzyme preparation was capable of hydrolyzing ADP, in addition to ATP, and several other nucleoside diphosphates and triphosphates. In contrast to the ATPase of animal mitochondria, the activity of the wheat enzyme was almost as insensitive to oligomycin in intact mitochondria as it was after isolation from the organelles.