Marcinkowska A, Wolny M
School of Medicine, Department of Biochemistry, Wrocław, Poland.
Acta Biochim Pol. 1988;35(2):83-94.
Glyceraldehyde-3-phosphate dehydrogenase was purified from carp white muscle. On CM-Sephadex chromatography two well separated active peaks were obtained. Both of them show a single protein band on gel electrophoresis and have the same molecular and kinetic properties; they differ only by the amount of bound NAD, the enzyme in the second peak being coenzyme-free. Significant differences were observed between the properties of carp and pig muscle enzymes. Glyceraldehyde-3-phosphate dehydrogenase from carp is more resistant to heat and proteolytic inactivation. Moreover NAD does not protect it against inactivation. Only one sulphydryl group per subunit is able to react with 5,5'-dithiobis(2-nitrobenzoate), irrespective of the kind of the buffer. The structure of glyceraldehyde-3-phosphate dehydrogenase from white muscle of carp seems to be more compact and therefore more inaccessible to some agents than that of the enzyme from pig muscle.
从鲤鱼白肌中纯化出3-磷酸甘油醛脱氢酶。在CM-葡聚糖凝胶柱层析上得到两个分离良好的活性峰。它们在凝胶电泳上均显示出一条单一的蛋白带，并且具有相同的分子和动力学性质；它们仅在结合的NAD量上有所不同，第二个峰中的酶不含辅酶。观察到鲤鱼和猪肌肉酶的性质之间存在显著差异。鲤鱼的3-磷酸甘油醛脱氢酶对热和蛋白水解失活更具抗性。此外，NAD不能保护它免于失活。无论缓冲液的种类如何，每个亚基只有一个巯基能够与5,5'-二硫代双（2-硝基苯甲酸）反应。鲤鱼白肌中的3-磷酸甘油醛脱氢酶的结构似乎更紧密，因此比猪肌肉中的酶更难被某些试剂作用。
