Storer A C, Cornish-Bowden A
Biochem J. 1977 Jul 1;165(1):61-9. doi: 10.1042/bj1650061.
Inhibition studies of glucokinase were carried out with the products of the reaction, glucose 6-phosphate and MgADP-, as well as with ADP3-, Mg2+ and ATP4-. The results of these, together with those of kinetic studies of the uninhibited reaction described previously [Storer & Cornish-Bowden (1976) Biochem. J. 159, 7-14], indicate that the enzyme obeys a 'mnemonical' mechanism. This implies that the co-operativity observed with glucose as substrate arises because glucose binds differentially to two forms of the free enzyme that are not in equilibrium under steady-state conditions. The mechanism predicts the decrease in glucose co-operativity observed at low concentrations of MgATP2-. The product-inhibition results suggest that glucose 6-phosphate is released first and that it is possibly displaced by MgATP2- in a concerted reaction.
用反应产物6-磷酸葡萄糖和MgADP⁻以及ADP³⁻、Mg²⁺和ATP⁴⁻对葡萄糖激酶进行了抑制研究。这些研究结果,连同先前描述的无抑制反应的动力学研究结果[斯托勒和科尼什-鲍登(1976年)《生物化学杂志》159, 7 - 14]表明,该酶遵循一种“记忆”机制。这意味着观察到以葡萄糖为底物时的协同性,是因为葡萄糖与两种游离酶形式的结合存在差异,而这两种形式在稳态条件下并非处于平衡状态。该机制预测了在低浓度MgATP²⁻时观察到的葡萄糖协同性降低。产物抑制结果表明,6-磷酸葡萄糖首先释放,并且它可能在协同反应中被MgATP²⁻取代。