Gold G, Widnell C C
J Biol Chem. 1976 Feb 25;251(4):1035-41.
Arion et al; (Arion, W. J., Wallin, B. K., Lange A. J., and Ballas, L. M. (1975) Mol. Cell. Biochem. 6, 75-83) propsed a model for glucose-6-phosphatase in which the substrate was transported across the microsomal membrane by a carrier before hydrolysis on the cisternal side. Evidence to support this model has been obtained by studying the inhibition of the enzyme by pyridoxal-P. Pyridoxal-P was a linear noncompetitive inhibitor of glucose-6-phosphatase (EC 3.1.3.9) in freshly isolated ("intact") microsomes from rat liver. Pyridoxol-P was a much less effective inhibitor and no inhibition was observed with pyridoxamine-P. When microsomes were subjected to nitrogen cavitation, treatment with solium deoxycholate, or glutaraldehyde fixation, the Km of glucose-6-phosphatase for glucose-6 P decreased from approximately 6 mM to approximately 2.5 mM; the corresponding change in the Vmax ranged from-10% to +40%. The same procedures decreased the inhibition of glucose-6-phosphatase by pyridoxal-P several-fold. No inhibition by pyridoxal-P was observed in a preparation of glucose-6-phosphatase purified approximately 20 fold (on the basis of Vmax) from micoromes. A nondialyzable inhibitor was apparently formed when intact microsomes were reacted with pyridoxal-P and NaBH4; this inhibition was also reversed by procedures which changed the kinetic properties of glucose-6-phosphatase.
阿里昂等人（阿里昂，W.J.，瓦林，B.K.，兰格，A.J.，以及巴拉斯，L.M.（1975年），《分子与细胞生物化学》第6卷，第75 - 83页）提出了一种葡萄糖 - 6 - 磷酸酶的模型，该模型认为底物在微粒体膜上通过载体转运，然后在内质网一侧水解。通过研究吡哆醛 - P对该酶的抑制作用，已获得支持此模型的证据。吡哆醛 - P是大鼠肝脏新鲜分离的（“完整的”）微粒体中葡萄糖 - 6 - 磷酸酶（EC 3.1.3.9）的线性非竞争性抑制剂。吡哆醇 - P是一种效果差得多的抑制剂，而吡哆胺 - P未观察到抑制作用。当微粒体进行氮空化、用脱氧胆酸钠处理或戊二醛固定时，葡萄糖 - 6 - 磷酸酶对葡萄糖 - 6 - P的Km值从约6 mM降至约2.5 mM；Vmax的相应变化范围为 - 10%至 + 40%。相同的处理方法使吡哆醛 - P对葡萄糖 - 6 - 磷酸酶的抑制作用降低了几倍。在从微粒体中纯化了约20倍（基于Vmax）的葡萄糖 - 6 - 磷酸酶制剂中未观察到吡哆醛 - P的抑制作用。当完整的微粒体与吡哆醛 - P和硼氢化钠反应时，显然形成了一种不可透析的抑制剂；这种抑制作用也可通过改变葡萄糖 - 6 - 磷酸酶动力学性质的方法来逆转。
