Lysine-21 of Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase participates in substrate binding through charge-charge interaction.
Lysine-21 of Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase participates in substrate binding through charge-charge interaction.
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肠膜明串珠菌葡萄糖 6-磷酸脱氢酶的赖氨酸 21 通过电荷-电荷相互作用参与底物结合。
DOI：
10.1002/pro.5560010304
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Levy,HR
中科院分区：
文献类型：
--
作者：
Lee,WT;Levy,HR
从一株缺乏自身葡萄糖- 6 -磷酸脱氢酶基因的大肠杆菌中高产地分离出肠系膜样Leuconostoc葡萄糖- 6 -磷酸脱氢酶（G6PD），并将其纯化至均质性。Lys - 21是酶中两个赖基残基之一，之前被亲和标记吡哆醛5′-磷酸和吡哆醛5′-二磷酸- 5′-腺苷修饰，它们是酶对葡萄糖6′-磷酸的竞争性抑制剂(LaDine， J.R, Carlow， D, Lee， W.T, Cross, r.l., Flynn， T.G, & Levy， H.R, 1991，J。医学杂志。化学。266,5558-5562)。对该酶的K21R和K21Q突变体进行了纯化，并对其进行了动力学表征，以确定其功能。与野生型酶相比，两种突变酶对葡萄糖6 -磷酸的km值均有所增加：K21R酶的km值分别为1.4倍（NAD连接反应）和2.1倍（NADP连接反应），K21Q酶的km值分别为36倍（NAD连接反应）和53倍（NADP连接反应）。两种突变酶的kmfor NADP+均未发生变化。与野生型酶相比，K21R和K21Q酶的km - for NAD+分别增加了1.5倍和3.2倍。对于K21R酶，NAD -和NADP -连锁反应的kcatt不变。与野生型酶相比，NAD - linked反应中K21Q酶的kcat值增加了26%，而在NADP - linked反应中则降低了30%。这些数据与Lys‐21通过电荷-电荷相互作用参与底物的磷酸基团与酶的结合一致。
Leuconostoc mesenteroidesglucose 6‐phosphate dehydrogenase (G6PD) was isolated in high yield and purified to homogeneity from a newly constructed strain ofEscherichia coliwhich lacks its own glucose 6‐phosphate dehydrogenase gene. Lys‐21 is one of two lysyl residues in the enzyme previously modified by the affinity labels pyridoxal 5′‐phosphate and pyridoxal 5′‐diphosphate‐5′‐adenosine, which are competitive inhibitors of the enzyme with respect to glucose 6‐phosphate (LaDine, J.R., Carlow, D., Lee, W.T., Cross, R.L., Flynn, T.G., & Levy, H.R., 1991,J. Biol. Chem. 266, 5558–5562). K21R and K21Q mutants of the enzyme were purified to homogeneity and characterized kinetically to determine the function of Lys‐21. Both mutant enzymes showed increasedKm‐values for glucose 6‐phosphate compared to wild‐type enzyme: 1.4‐fold (NAD‐linked reaction) and 2.1‐fold (NADP‐linked reaction) for the K21R enzyme, and 36‐fold (NAD‐linked reaction) and 53‐fold (NADP‐linked reaction) for the K21Q enzyme. TheKmfor NADP+was unchanged in both mutant enzymes. TheKmfor NAD+was increased 1.5‐ and 3.2‐fold, compared to the wild‐type enzyme, in the K21R and K21Q enzymes, respectively. For the K21R enzyme thekcatfor the NAD‐ and NADP‐linked reactions was unchanged. Thekcatfor the K21Q enzyme was increased in the NAD‐linked reaction by 26% and decreased by 30% in the NADP‐linked reaction from the values for the wild‐type enzyme. The data are consistent with Lys‐21 participating in the binding of the phosphate group of the substrate to the enzyme via charge–charge interaction.
影响因子：
12.7
作者：
BURACK, RC;LIANG, J
通讯作者：
LIANG, J
在临床实践中最大限度地提高结肠癌血潜筛查的合规性
影响因子：
3
作者：
R. Thompson;M. Michnich;J. Gray;L. Friedlander;B. Gilson
通讯作者：
B. Gilson
初级保健环境中癌症的早期发现：与接受和完成推荐程序相关的因素。
影响因子：
5.1
作者：
R. Burack;Jersey Liang
通讯作者：
Jersey Liang