Adapoe C, Silver M
Can J Microbiol. 1975 Jan;21(1):1-7. doi: 10.1139/m75-001.
Adenosine triphosphatase (ATPase) from Thiobacillus ferrooxidans was purified 55-fold. Polyacrylamide gel electrophoresis of the most purified fraction showed only one major band; histochemical analysis showed that the ATPase activity was associated with this band. The pH optimum is 9-10. The enzyme hydrolyzed ATP stoichiometrically to ADP and inorganic phosphate, the Km for this substrate being 7.75 times 10-3 M. GTP and ITP are alternate substrates, the Km values for these being 6.71 times 10-3 M and 3.12 times 10-3 M, respectively. ADP is slightly hydrolyzed. Magnesium, manganese, and calcium can serve as cofactors; Km values for these are 2.0 times 10-3 M, 9.4 times 10-4 M, and 8.0 times 10-4 M, respectively. The enzyme activity was not activated by either sodium or potassium, but a combination of the two ions were inhibitory. Azide and p-hydroxymercuribenzoate strongly inhibited the enzyme activity, whereas cyanide, dinitrophenol, and N,N'-dicyclohexylcarbodiimide (DCCD) were without effect. The enzyme was cold labile at 0 degrees-C, but was more stable at 18-24 degrees-C.
从氧化亚铁硫杆菌中纯化出的三磷酸腺苷酶（ATP酶），纯化倍数为55倍。对纯化程度最高的部分进行聚丙烯酰胺凝胶电泳，结果显示只有一条主要条带；组织化学分析表明，ATP酶活性与这条带相关。最适pH值为9 - 10。该酶将ATP化学计量地水解为ADP和无机磷酸，此底物的米氏常数（Km）为7.75×10⁻³ M。GTP和ITP是替代底物，它们的Km值分别为6.71×10⁻³ M和3.12×10⁻³ M。ADP可被轻微水解。镁、锰和钙可作为辅助因子；它们的Km值分别为2.0×10⁻³ M、9.4×10⁻⁴ M和8.0×10⁻⁴ M。该酶活性既不被钠也不被钾激活，但这两种离子的组合具有抑制作用。叠氮化物和对羟基汞苯甲酸强烈抑制该酶活性，而氰化物、二硝基苯酚和N,N'-二环己基碳二亚胺（DCCD）则无作用。该酶在0℃时对冷不稳定，但在18 - 24℃时更稳定。
