Tsuboi K K, Chervenka C H
J Biol Chem. 1975 Jan 10;250(1):132-40.
Adenylate kinase exists in the human erythrocyte in a number of molecular forms with two allels at a single polymorphic locus coding for most of the enzyme forms. The predominant enzyme form, AK a, was purified to constant specific activity in excess of 3000 and appeared homogeneous by chromatography, electrophoresis, and ultracentrifugation. Sedimentation velocity and partial specific volume measurments of AK a yielded values of s20,w = 2.1 S and 0.722 cm-3per g. The molecular weight of the native enzyme was estimated to be 22,500 by sedimentation equilibrium and gel filtration analyses. The molecular weight of the denatured enzyme did not differ, indicating an absence of subunit structure in confirmation of genetic evidence of a single locus coding for the enzyme. The isolated enzyme demonstrated remarkable stability to denaturants (heat, guanidine HCl, urea) in the presence of appropriate stabilizing agents and could not be distinguished from rabbit muscle enzyme on this basis (as well as by a number of other kinetic and physicochemical parameters). The erythrocyte adenylate kinases have a common molecular size but differ in their charge properties. They demonstrate anomalous electrophoretic behavior, migrating anionic to hemoglobin in starch gel, yet exhibit isoelectric points considerably alkaline to hemoglobin (e.g. AK a, pI = 9.0) by isoelectric focusing.
腺苷酸激酶在人类红细胞中以多种分子形式存在，在一个单一的多态位点上有两个等位基因，编码大多数酶形式。主要的酶形式AK a被纯化至比活性超过3000且恒定，通过色谱法、电泳法和超速离心法显示为均一。AK a的沉降速度和比容测量得出s20,w = 2.1 S和0.722 cm³/g的值。通过沉降平衡和凝胶过滤分析估计天然酶的分子量为22,500。变性酶的分子量没有差异，这表明不存在亚基结构，从而证实了该酶由单个位点编码的遗传证据。在适当的稳定剂存在下，分离出的酶对变性剂（热、盐酸胍、尿素）表现出显著的稳定性，并且在此基础上（以及通过许多其他动力学和物理化学参数）与兔肌肉酶无法区分。红细胞腺苷酸激酶具有共同的分子大小，但电荷性质不同。它们表现出异常的电泳行为，在淀粉凝胶中向血红蛋白阴离子迁移，但通过等电聚焦显示其等电点比血红蛋白碱性强得多（例如AK a，pI = 9.0）。
