Applied Environmental Biology Laboratory, Graduate School of Pharmaceutical Sciences, Osaka University.
Biochemical Laboratory, Saraya Co., Ltd.
Biol Pharm Bull. 2021;44(12):1832-1836. doi: 10.1248/bpb.b21-00494.
γ-Glutamylcysteine (γ-EC) has antioxidant properties similar to those of glutathione (GSH) and acts as its precursor in mammals. There are a few procedures for the production of γ-EC, such as chemical synthesis or enzymatic synthesis from glutamate and cysteine; however, they are very costly and not suitable for industrial production. A phytochelatin synthase-like enzyme derived from Nostoc sp. Pasteur Culture Collection 7120 (NsPCS) catalyzes the hydrolysis of GSH to γ-EC and glycine in the absence of ATP or other additives. Our research aims to establish an alternative γ-EC production procedure with low cost and high productivity. To this end, we optimized the reaction conditions of NsPCS and characterized its properties in this study. We found that 200 mM potassium phosphate buffer, pH 8.0, at 37 °C, had the highest NsPCS activity among the conditions we tested. Under these conditions, NsPCS had a K of 385 µM and a V of 26 mol/min/mg-protein. In addition, NsPCS converted 100 mM GSH into γ-EC with high yields. These results suggest that the NsPCS reaction has great potential for the low-cost, industrial-scale production of γ-EC.
γ-谷氨酰半胱氨酸（γ-EC）具有与谷胱甘肽（GSH）相似的抗氧化性质，并且在哺乳动物中作为其前体发挥作用。有几种生产 γ-EC 的方法，例如化学合成或从谷氨酸和半胱氨酸的酶促合成；然而，它们非常昂贵，不适合工业生产。来自念珠藻属 Pasteur 培养物收集 7120（NsPCS）的植物螯合肽合酶样酶在没有 ATP 或其他添加剂的情况下催化 GSH 水解为 γ-EC 和甘氨酸。我们的研究旨在建立一种具有低成本和高生产力的替代 γ-EC 生产方法。为此，我们优化了 NsPCS 的反应条件，并在本研究中对其性质进行了表征。我们发现，在我们测试的条件中，200 mM 磷酸钾缓冲液，pH 值 8.0，在 37°C 时，具有最高的 NsPCS 活性。在这些条件下，NsPCS 的 K 值为 385 μM，V 值为 26 mol/min/mg-蛋白。此外，NsPCS 将 100 mM GSH 转化为 γ-EC，产率很高。这些结果表明，NsPCS 反应具有在低成本、工业规模生产 γ-EC 的巨大潜力。
