小球藻 ADP-葡萄糖焦磷酸化酶的调节。
Regulation of ADP-Glucose Pyrophosphorylase from Chlorella vulgaris.
机构信息
Radioisotope Centre, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113, Japan.
出版信息
Plant Physiol. 1985 Jul;78(3):601-5. doi: 10.1104/pp.78.3.601.
ADP-glucose pyrophosphorylase was partially purified from Chlorella vulgaris 11h. 3-Phosphoglycerate activated the enzyme by lowering the Michaelis constant for glucose-1-phosphate (from 0.97 to 0.36 millimolar in the presence of 2 millimolar phosphoglycerate) and ATP (from 0.23 to 0.10 millimolar), as well as increasing the V(max). Saturation curves for 3-phosphoglycerate were hyperbolic and the activator concentration at half V(max) value for 3-phosphoglycerate was 0.41 millimolar either in the presence or absence of phosphate. Phosphate inhibited the enzyme in a competitive manner with respect to glucose-1-phosphate, but did not affect the Michaelis constant value for ATP. 3-Phosphoglycerate changed neither the inhibitor concentration at half V(max) value of 1.0 millimolar for phosphate nor the hyperbolic inhibition kinetics for phosphate. The enzyme required divalent cations for its activity. The activation curves for Mn(2+) and Mg(2+) were highly sigmoidal. The activator concentration at half V(max) values for Mn(2+) and Mg(2+) were 2.8 and 3.7 millimolar, respectively. With optimal cations, the Michaelis constant values for ATP-Mn and ATP-Mg were 0.1 and 0.4 millimolar, respectively.
从普通小球藻 11h 中部分纯化 ADP-葡萄糖焦磷酸化酶。3-磷酸甘油酸通过降低葡萄糖-1-磷酸的米氏常数（在存在 2 毫摩尔 3-磷酸甘油酸的情况下从 0.97 降低至 0.36 毫摩尔）和 ATP（从 0.23 降低至 0.10 毫摩尔），以及增加 Vmax，来激活该酶。3-磷酸甘油酸的饱和曲线呈双曲线形，并且在有或没有磷酸盐的情况下，3-磷酸甘油酸的 Vmax 值的一半的激活剂浓度为 0.41 毫摩尔。磷酸盐以竞争性方式抑制该酶对葡萄糖-1-磷酸的作用，但不影响 ATP 的米氏常数值。3-磷酸甘油酸既不改变磷酸盐的 Vmax 值的一半的抑制剂浓度为 1.0 毫摩尔，也不改变磷酸盐的双曲线抑制动力学。该酶的活性需要二价阳离子。Mn(2+)和 Mg(2+)的激活曲线呈高度 S 形。Mn(2+)和 Mg(2+)的 Vmax 值的一半的激活剂浓度分别为 2.8 和 3.7 毫摩尔。在最佳阳离子存在下，ATP-Mn 和 ATP-Mg 的米氏常数值分别为 0.1 和 0.4 毫摩尔。
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