Lee K Y
Zhonghua Min Guo Wei Sheng Wu Xue Za Zhi. 1978 Mar;11(1):21-9.
In vitro assembly of Neurospora crassa NADPH-nitrate reductase (EC1.6.6.2) could be effected by combing the nitrate induced Neurospora crassa mutant nit-1 with the extract of any known molybdenum-containing enzyme. The process involves the participation of a molybdenum-cofactor contributed by the molybdenum-enzyme fraction. This paper emphasizes two points: Firstly, the indispensable role played by EDTA in the viability of Mo-cofactor and secondly, the nature of Mo-cofactor predicated by our previous work is supported by concrete experimental results. Recent experiments with Chelax-100 column provide evidence that the in vitro formation of Neurospora NADPH-nitrate reductase involves EDTA and the latter may take part in the formation of a molybdenum, labile sulfide and EDTA complex. In addition to 10(-2) M sodium molybdate, both EDTA and reducing agent are required to activate the cofactor in the Chelax-100 column eluate. The cofactor is of low molecular weight and devoid of protein as was predicated. To substantiate those predications, concrete experimental results are provided.
通过将硝酸盐诱导的粗糙脉孢菌突变体nit-1与任何已知含钼酶的提取物相结合，可实现粗糙脉孢菌NADPH-硝酸还原酶（EC1.6.6.2）的体外组装。该过程涉及钼酶组分提供的钼辅因子的参与。本文强调两点：第一，EDTA在钼辅因子活性方面发挥的不可或缺的作用；第二，我们之前工作所预测的钼辅因子的性质得到了具体实验结果的支持。最近使用Chelax-100柱的实验提供了证据，表明粗糙脉孢菌NADPH-硝酸还原酶的体外形成涉及EDTA，并且后者可能参与钼、不稳定硫化物和EDTA复合物的形成。除了10⁻² M钼酸钠外，还需要EDTA和还原剂来激活Chelax-100柱洗脱液中的辅因子。如所预测的那样，该辅因子分子量低且不含蛋白质。为证实这些预测，提供了具体的实验结果。
