Domenech C E, Lisa T A, Salvano M A, Garrido M N
Departamento de Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de Río Cuarto, Córdoba, Argentina.
FEBS Lett. 1992 Mar 24;299(1):96-8. doi: 10.1016/0014-5793(92)80108-s.
In Pseudomonas aeruginosa, the effect of different cations on the acid phosphatase activity was studied in order to acquire more information related to a previously proposed mechanism, involving the coordinated action of this enzyme with phospholipase C. Although the natural substrate of this enzyme is phosphorylcholine, in order to avoid the possible interaction of its positive charge and those of the different cations with the enzyme molecule, the artificial substrate p-nitrophenylphosphate was utilized. Kinetic studies of the activation of acid phosphatase (phosphorylcholine phosphatase) mediated by divalent cations Mg2+, Zn2+ and Cu2+ revealed that all these ions bind to the enzyme in a compulsory order (ordered bireactant system). The Km values obtained for p-NPP in the presence of Mg2+, Zn2+ and Cu2+ were 1.4 mM, 1.0 mM and 3.5 mM, respectively. The KA values for the same ions were 1.25 mM, 0.05 mM and 0.03 mM, respectively. The Vmax obtained in the presence of Cu2+ was about twofold higher than that obtained in the presence of Mg2+ or Zn2+. The inhibition observed with Al3+ seems to be a multi-site inhibition. The K'app and n values, from the Hill plot, were about 0.25 mM and 4.0 mM, respectively, which were independent of the metal ion utilized as activator. It is proposed that the acid phosphatase may exert its action under physiological conditions, depending on the availability of either one of these metal ions.
在铜绿假单胞菌中，研究了不同阳离子对酸性磷酸酶活性的影响，以便获取更多与先前提出的一种机制相关的信息，该机制涉及这种酶与磷脂酶C的协同作用。尽管这种酶的天然底物是磷酸胆碱，但为了避免其正电荷以及不同阳离子的正电荷与酶分子之间可能的相互作用，使用了人工底物对硝基苯磷酸酯。对由二价阳离子Mg2+、Zn2+和Cu2+介导的酸性磷酸酶（磷酸胆碱磷酸酶）激活的动力学研究表明，所有这些离子都以强制顺序与酶结合（有序双反应物系统）。在Mg2+、Zn2+和Cu2+存在下，对硝基苯磷酸酯的Km值分别为1.4 mM、1.0 mM和3.5 mM。相同离子的KA值分别为1.25 mM、0.05 mM和0.03 mM。在Cu2+存在下获得的Vmax比在Mg2+或Zn2+存在下获得的Vmax高约两倍。观察到的Al3+抑制似乎是一种多位点抑制。从希尔图得到的K'app和n值分别约为0.25 mM和4.0 mM，这与用作激活剂的金属离子无关。有人提出，酸性磷酸酶可能在生理条件下发挥作用，这取决于这些金属离子中任何一种的可用性。
