REGULATION OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE IN BLUE-GREEN-ALGAE
REGULATION OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE IN BLUE-GREEN-ALGAE
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DOI：
10.1104/pp.55.4.658
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发表时间：
1975-01-01
期刊：
影响因子：
7.4
通讯作者：
MCGOWAN, RE
中科院分区：
文献类型：
--
作者：
GROSSMAN, A;MCGOWAN, RE
用硫酸铵分级沉淀和凝胶层析的方法从水华鱼腥藻和水华鱼腥藻中分离纯化了葡萄糖6-磷酸脱氢酶(EC 1.1.1.49)，并测定了其动力学性质。在此pH下测得葡萄糖-6-磷酸的Km值为0.37mM，NADP的Km值为10μm。当pH高于7.4时，该酶对6-磷酸葡萄糖的饱和度呈S形动力学，但对NADP的饱和曲线仍为双曲线，ATP是该酶的抑制剂，Ki2~5 mM。NADPH与葡萄糖6-磷酸竞争抑制该酶。对NADPH的抑制曲线在pH 6.7时呈双曲线，在pH 8.6时呈S形。结合活体实验数据，讨论了这些曲线在控制蓝藻葡萄糖6-磷酸代谢中的意义。
Glucose 6-phosphate dehydrogenase (EC 1.1.1.49) has been partially purified fromAnacystis nidulansandAnabaena flos-aquaeby means of ammonium sulfate fractionation and exclusion gel chromatography and the kinetic properties determined.Glucose 6-phosphate dehydrogenase from these blue-green algae exhibits Michaelis-Menten kinetics at pH 6.7. At this pH, Kmvalues of 0.37 mmfor glucose 6-phosphate and 10 μmfor NADP were determined. At a pH above 7.4, the enzyme exhibits sigmoidal kinetics with respect to glucose 6-phosphate saturation but the saturation curve for NADP remains hyperbolic.ATP is an inhibitor of the enzyme competitively with NADP with a Kiof 2 to 5 mm. NADPH inhibits the enzyme competitively with glucose 6-phosphate. The inhibition curves for NADPH are hyperbolic at pH 6.7 and sigmoidal at pH 8.6.The significance of thesein vitrokinetics are discussed relative toin vivodata on the control of glucose 6-phosphate turnover in blue-green algae.