Isolation and Kinetic Analyses of the Soluble ¥i ATPases from Mitochondria of Wheat and Pearlmillet

Aniruddha P. Sane and Vidhu A. Sane Centre for Plant Molecular Biology, National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, India Z. Naturforsch. 53c, 341-346 (1998); received December 12, 1997/January 22, 1998 F] ATPase, Purification, Kinetics, Wheat, Pearlmillet The mitochondrial F j ATPases from two cereal crops, wheat and pearlmillet, were purified and studied. The wheat F, ATPase could be purified to homogeneity and is apparently com­ posed of six subunits with apparent molecular weights of 55 kDa (a and ß), 35 kDa (y), 26 kDa (8 ’) and 22 kDa (8 ). The e subunit was barely detectable. Both enzymes reveal typical non-linear kinetics but show variability in their response to bicarbonate and chloride. While the wheat F, ATPase is stimulated by bicarbonate and chloride, the pearlmillet F j ATPase is inhibited by both anions. The two enzymes are Mg2+ dependent ATPases and are competi­ tively inhibited by Ca2+, unlike maize, pea and turnip ATPases. Both the enzymes also pos­ sess a GTPase activity which is two fold higher than the ATPase, unlike rice, sorghum and oat root Fj ATPases.