A previous study showed that 2′-3′-O-(2,4,6-trinitrophenyl) adenosine 5′-triphosphate (TNP-ATP) was a weak allosteric activator of Rhizobium etli pyruvate carboxylase (RePC) in the absence of acetyl-CoA. On the other hand, TNP-ATP inhibited the allosteric activation of RePC by acetyl-CoA. Here, we aimed to study the role of triphosphate group of TNP-ATP on its allosteric activation of the enzyme and inhibition of acetyl-CoA-dependent activation of RePC using TNP-ATP and its derivatives, including TNP-ADP, TNP-AMP and TNP-adenosine. The pyruvate carboxylation activity was assayed to determine the effect of reducing the number of phosphate groups in TNP-ATP derivatives on allosteric activation and inhibition of acetyl-CoA activation of RePC and chicken liver pyruvate carboxylase (CLPC). Reducing the number of phosphate groups in TNP-ATP derivatives decreased the activation efficacy for both RePC and CLPC compared to TNP-ATP. The apparent binding affinity and inhibition of activation of the enzymes by acetyl-CoA were also diminished when the number of phosphate groups in the TNP-ATP derivatives was reduced. Whilst TNP-AMP activated RePC, it did not activate CLPC, but it did inhibit acetyl-CoA activation of both RePC and CLPC. Similarly, TNP-adenosine did not activate RePC; however, it did inhibit acetyl-CoA activation using a different mechanism compared to phosphorylated TNP-derivatives. These findings indicate that mechanisms of PC activation and inhibition of acetyl-CoA activation by TNP-ATP and its derivatives are different. This study provides the basis for possible drug development for treatment of metabolic diseases and cancers with aberrant expression of PC.

先前的一项研究表明，2'-3'-O-(2,4,6-三硝基苯基) 腺苷 5'-三磷酸 (TNP-ATP) 是根瘤菌的弱变构激活剂丙酮酸羧化酶 (RePC) 在没有乙酰辅酶 A 的情况下。另一方面，TNP-ATP 抑制了乙酰辅酶 A 对 RePC 的变构激活。在这里，我们的目的是研究 TNP-ATP 的三磷酸基团在其变构激活酶和使用 TNP-ATP 及其衍生物（包括 TNP-ADP、TNP-AMP 和TNP-腺苷。测定丙酮酸羧化活性以确定减少 TNP-ATP 衍生物中磷酸基团的数量对 RePC 和鸡肝丙酮酸羧化酶 (CLPC) 的变构激活和乙酰辅酶 A 激活的抑制的影响。与 TNP-ATP 相比，减少 TNP-ATP 衍生物中磷酸基团的数量降低了 RePC 和 CLPC 的活化功效。当 TNP-ATP 衍生物中磷酸基团的数量减少时，乙酰辅酶 A 对酶活化的表观结合亲和力和抑制作用也减弱。虽然 TNP-AMP 激活 RePC，但它不激活 CLPC，但它确实抑制 RePC 和 CLPC 的乙酰辅酶 A 激活。同样，TNP-腺苷不激活 RePC；然而，与磷酸化的 TNP 衍生物相比，它确实使用不同的机制抑制了乙酰辅酶 A 的激活。这些发现表明TNP-ATP及其衍生物激活PC和抑制乙酰辅酶A激活的机制不同。该研究为治疗代谢性疾病和 PC 异常表达的癌症的可能药物开发提供了基础。