Covalent modification as the cause of the anomalous kinetics of aryl sulfatase A.
Covalent modification as the cause of the anomalous kinetics of aryl sulfatase A.
复制标题
共价修饰是芳基硫酸酯酶 A 异常动力学的原因。
DOI：
10.1016/0003-9861(79)90348-5
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发表时间：
1979
影响因子：
3.9
通讯作者：
R. V. Van Etten
中科院分区：
文献类型：
--
作者：
A. Waheed;R. V. Van Etten
已知哺乳动物芳基硫酸酯酶A表现出异常的动力学行为，其中酶在催化底物水解时变得失活。这种失活的、营业额改变的酶的部分活性显然可以通过底物和硫酸根离子的同时存在而恢复。目前的实验，2-羟基-5-硝基苯基[35 S]硫酸盐（硝基儿茶酚硫酸盐）进行，建立周转修饰的酶共价标记。掺入放射性的化学计量相当于每摩尔酶单体2克35 S原子（兔肝芳基硫酸酯酶的每个单体由两个等价的亚基组成）。它还表明，分离的，营业额修饰的酶已经失去了80%的二级结构相比，天然酶。一种常用的硫酸化剂，吡啶-三氧化硫复合物导致活性和二级结构的类似损失。
Mammalian aryl sulfatase A enzymes are known to exhibit an anomalous kinetic behavior in which the enzyme becomes inactivated as it catalyzes the hydrolysis of substrate. Part of the activity of this inactive, turnover-modified form of the enzyme can apparently be restored by the simultaneous presence of substrate and sulfate ion. The present experiments, conducted with 2-hydroxy-5-nitrophenyl [35S]sulfate (nitrocatechol sulfate), establish that the turnover-modified enzyme is covalently labeled. The stoichiometry of the incorporation of radioactivity corresponds to 2 g atom of35S per mole of enzyme monomer (each monomer of rabbit liver aryl sulfatase consists of two equivalent subunits). It is also shown that isolated, turnover-modified enzyme has lost 80% of its secondary structure when compared to the native enzyme. A commonly used sulfating agent, pyridine-sulfur trioxide complex brings about a similar loss of activity and of secondary structure.