Hsu H H, Anderson H C
Int J Biochem. 1986;18(12):1141-6. doi: 10.1016/0020-711x(86)90089-3.
About 5 mumol CaPPi/mg protein was deposited within 3 h in the presence of the reaction mixtures containing 1 mM ATP, 2 mM Ca2+, 1 mM Pi, and 17 micrograms of purified NTP pyrophosphohydrolase. At 1 mM ATP, 50% of the deposition was inhibited by 0.5-1 mM of various substrate and product analogues including AMP, ADP, and ethylene hydroxyl diphosphonate. The magnitude of inhibition on NTP pyrophosphohydrolase activity was in the order of AMP = CMP = ADP greater than adenosine greater than adenine greater than NAD = NADP. AMP, CMP, ADP, and adenosine are competitive inhibitors. The modes of inhibition by adenine, NAD, and NADP differ from the competitive inhibition. Ribose, 3'-AMP, 2'-AMP, and cAMP did not inhibit the enzyme activity.
在含有1 mM ATP、2 mM Ca²⁺、1 mM无机磷酸（Pi）和17微克纯化的NTP焦磷酸水解酶的反应混合物存在的情况下，约5微摩尔焦磷酸钙（CaPPi）/毫克蛋白质在3小时内沉积。在1 mM ATP时，0.5 - 1 mM的各种底物和产物类似物（包括AMP、ADP和乙烯羟基二膦酸盐）可抑制50%的沉积。对NTP焦磷酸水解酶活性的抑制程度顺序为AMP = CMP = ADP大于腺苷大于腺嘌呤大于NAD = NADP。AMP、CMP、ADP和腺苷是竞争性抑制剂。腺嘌呤、NAD和NADP的抑制模式与竞争性抑制不同。核糖、3'-AMP、2'-AMP和cAMP不抑制该酶的活性。
