Kristjansson H, Hochstein L I
Arch Biochem Biophys. 1985 Sep;241(2):590-5. doi: 10.1016/0003-9861(85)90584-3.
Membranes from Halobacterium saccharovorum contained a cryptic ATPase which required Mg2+ or Mn2+ and was activated by Triton X-100. The optimal pH for ATP hydrolysis was 9-10. ATP or GTP were hydrolyzed at the same rate while ITP, CTP, and UTP were hydrolyzed at about half that rate. The products of ATP hydrolysis were ADP and phosphate. The ATPase required high concentrations (3.5 M) of NaCl for maximum activity. ADP was a competitive inhibitor of the activity, with an apparent Ki of 50 microM. Dicyclohexylcarbodiimide (DCCD) inhibited ATP hydrolysis. The inhibition was marginal at the optimum pH of the enzyme. When the ATPase was preincubated with DCCD at varying pH values, but assayed at the optimal pH for activity, DCCD inhibition was observed to increase with increasing acidity of the preincubation medium. DCCD inhibition was also dependent on time of preincubation, and protein and DCCD concentrations. When preincubated at pH 6.0 for 4 h at a protein:DCCD ratio of 40 (w/w), ATPase activity was inhibited 90%.
嗜糖嗜盐菌的膜中含有一种隐性ATP酶，该酶需要Mg2+或Mn2+，并可被 Triton X-100激活。ATP水解的最适pH为9 - 10。ATP或GTP以相同的速率水解，而ITP、CTP和UTP的水解速率约为前者的一半。ATP水解的产物是ADP和磷酸。该ATP酶需要高浓度（3.5M）的NaCl才能达到最大活性。ADP是该活性的竞争性抑制剂，表观Ki为50μM。二环己基碳二亚胺（DCCD）抑制ATP水解。在酶的最适pH下，抑制作用较弱。当ATP酶在不同pH值下与DCCD预孵育，但在活性最适pH下进行测定时，观察到DCCD抑制作用随着预孵育培养基酸度的增加而增强。DCCD抑制作用还取决于预孵育时间、蛋白质和DCCD浓度。当在pH 6.0下以蛋白质：DCCD比例为40（w/w）预孵育4小时时，ATP酶活性被抑制90%。
