Lestas A N, White J M
Ann Clin Biochem. 1983 Jul;20 (Pt 4):241-6. doi: 10.1177/000456328302000411.
gamma-Glutamylcysteine synthetase catalyses the combination of L-glutamate and L-cysteine to form gamma-glutamylcysteine with a stoichiometric conversion of ATP to ADP and inorganic phosphate (Pi). During the estimation of this enzyme in haemolysates from normal erythrocytes it was found that the Pi released was more than the amount of gamma-glutamylcysteine synthesised. Furthermore, the activity estimated by analysing either product was higher than the corresponding values reported in the literature. An investigation into these discrepancies resulted in improvements of the assay methods which produced two substantially different normal ranges for the gamma-glutamylcysteine synthetase activity in haemolysates: one derived from the Pi released and the other from the gamma-glutamylcysteine synthesised during the enzymatic reaction.
γ-谷氨酰半胱氨酸合成酶催化L-谷氨酸和L-半胱氨酸结合形成γ-谷氨酰半胱氨酸，同时ATP化学计量地转化为ADP和无机磷酸（Pi）。在对正常红细胞溶血产物中的这种酶进行测定时，发现释放的Pi量多于合成的γ-谷氨酰半胱氨酸量。此外，通过分析任一产物估算的活性均高于文献报道的相应值。对这些差异进行研究后改进了测定方法，这使得溶血产物中γ-谷氨酰半胱氨酸合成酶活性产生了两个截然不同的正常范围：一个来自释放的Pi，另一个来自酶促反应过程中合成的γ-谷氨酰半胱氨酸。
