Penefsky H S
J Biol Chem. 1977 May 10;252(9):2891-9.
Beef heart mitochondrial ATPase (F1) exhibited a single binding site for Pi. The interaction with Pi was reversible, partially dependent on the presence of divalent metal ions, and characterized by a dissociation constant at pH 7.5 of 80 micronM. A variety of substances known to influence oxidative phosphorylation or the activity of the soluble ATPase (F1) also influenced Pi binding by the enzyme. Thus aurovertin, an inhibitor of oxidative phosphorylation, which was bound tightly by F1 and inhibited ATPase activity, enhanced Pi binding via a 4-fold increase in the affinity of the enzyme for Pi (KD = 20 micronM) but did not alter binding stoichiometry. Anions such as SO4(2-), SO3(2-), chromate, and 2,4-dinitrophenolate, which stimulated ATPase activity of F1, also enhanced Pi binding. Inhibitors of ATPase activity such as nickel/bathophenanthroline and the protein ATPase inhibitor of Pullman and Monroy (Pullman, M. E., and Monroy, G. C. (1963) J. Biol. Chem. 238, 3762-3769) inhibited Pi binding. The adenine nucleotides ADP, ATP, and the ATP analog adenylyl imidodiphosphate as well as the Pi analog arsenate, also inhibited Pi binding. The observations suggest that the Pi binding site was located in or near an adenine nucleotide binding site on the molecule.
牛心线粒体ATP酶（F1）表现出对无机磷酸（Pi）的单一结合位点。与Pi的相互作用是可逆的，部分依赖于二价金属离子的存在，并且在pH 7.5时的解离常数为80微摩尔。多种已知会影响氧化磷酸化或可溶性ATP酶（F1）活性的物质也会影响该酶与Pi的结合。因此，氧化磷酸化抑制剂金褐霉素能与F1紧密结合并抑制ATP酶活性，它通过使酶对Pi的亲和力增加4倍（解离常数KD = 20微摩尔）来增强Pi结合，但不改变结合化学计量。诸如硫酸根离子（SO4(2-)）、亚硫酸根离子（SO3(2-)）、铬酸根离子和2,4-二硝基苯酚盐等阴离子，它们能刺激F1的ATP酶活性，也会增强Pi结合。ATP酶活性抑制剂如镍/红菲绕啉以及普尔曼和蒙罗的蛋白质ATP酶抑制剂（普尔曼，M. E.，和蒙罗，G. C.（1963年）《生物化学杂志》238卷，3762 - 3769页）会抑制Pi结合。腺嘌呤核苷酸二磷酸腺苷（ADP）、三磷酸腺苷（ATP）、ATP类似物腺苷酰亚胺二磷酸以及Pi类似物砷酸盐也会抑制Pi结合。这些观察结果表明，Pi结合位点位于分子上的腺嘌呤核苷酸结合位点内或其附近。
