Leone F A, Ciancaglini P, Pizauro J M, Rezende A A
Departamento de Química, Faculdade de Filosofia, Ciências e Letras/USP, Ribeirão Preto, Brasil.
Biometals. 1995 Jan;8(1):86-91. doi: 10.1007/BF00156163.
Polidocanol-solubilized osseous plate alkaline phosphatase was modulated by manganese ions in a similar way as by zinc ions. For concentrations up to 1.0 nM, the enzyme was stimulated by manganese ions, showing site-site interactions (n = 2.2). However, larger concentrations (> 0.1 microns) were inhibitory. Manganese ions could play the role of zinc ions stimulating the enzyme synergistically in the presence of magnesium ions (Kd = 7.2 microns; V = 1005.5 U mg-1). Manganese ions could also play the role of magnesium ions, stimulating the enzyme synergistically in the presence of zinc ions (Kd = 2.2 microns; V = 1036.7 U mg-1). However, manganese ions could not substitute for zinc and magnesium at the same time since ion assymetry is necessary for full activity of the enzyme. A steady-state kinetic model for the modulation of enzyme activity by manganese ions is proposed.
聚多卡醇增溶的骨板碱性磷酸酶受锰离子调节的方式与受锌离子调节的方式相似。对于浓度高达1.0 nM的情况，该酶受锰离子刺激，表现出位点间相互作用（n = 2.2）。然而，更高的浓度（> 0.1微摩尔）具有抑制作用。在镁离子存在下，锰离子可起到协同刺激该酶的锌离子的作用（解离常数Kd = 7.2微摩尔；V = 1005.5 U mg-1）。锰离子也可起到镁离子的作用，在锌离子存在下协同刺激该酶（Kd = 2.2微摩尔；V = 1036.7 U mg-1）。然而，由于离子不对称性对于该酶的完全活性是必需的，锰离子不能同时替代锌离子和镁离子。提出了一个关于锰离子调节酶活性的稳态动力学模型。
