Zantema A, de Smet M J, Robillard G T
Eur J Biochem. 1979 Jun 1;96(3):465-76. doi: 10.1111/j.1432-1033.1979.tb13059.x.
ADP and ATP with a spin-label linked to the terminal phosphate are activators of glutamate dehydrogenase and bind to the same site as the activator ADP. There is hardly any interaction with the coenzyme site. Glutamate dehydrogenase can be modified with a ketone spin-label at a site in the active centre[Andree and Zantema, (1978) Biochemistry, 17, 778--783]. The spin-labelled activators interact with ketone spin-labelled glutamate dehydrogenase in the same way as with native glutamate dehydrogenase relative to the activator site, but show a stronger binding to the coenzyme site. Upon binding to the coenzyme site a spin-spin interaction between the ketone spin-label and the spin-labelled activators is observed. Nuclear magnetic resonance studies of the linewidth of 2-oxoglutarate and NADP+ bound to their functional sites on glutamate dehydrogenase without and with spin-labels result in distances between the ligand nuclei and the spin-labels. The results show that NADP+ binds in an open conformation consistent with the conformation in other dehydrogenases. The activator ADP binds in the neighbourhood of the active centre, but with very little or no overlap with the coenzyme site.
与末端磷酸基团相连的带有自旋标记的二磷酸腺苷（ADP）和三磷酸腺苷（ATP）是谷氨酸脱氢酶的激活剂，且与激活剂ADP结合在同一部位。它们与辅酶部位几乎没有相互作用。谷氨酸脱氢酶可在活性中心的一个位点用酮自旋标记进行修饰[安德烈和赞特马，（1978年）《生物化学》，17卷，778 - 783页]。自旋标记的激活剂与酮自旋标记的谷氨酸脱氢酶在相对于激活剂位点上，与天然谷氨酸脱氢酶的相互作用方式相同，但对辅酶部位的结合更强。当与辅酶部位结合时，观察到酮自旋标记与自旋标记的激活剂之间存在自旋 - 自旋相互作用。对未标记和带有自旋标记的谷氨酸脱氢酶上与其功能位点结合的2 - 氧代戊二酸和烟酰胺腺嘌呤二核苷酸磷酸（NADP⁺）的线宽进行核磁共振研究，得出配体核与自旋标记之间的距离。结果表明，NADP⁺以与其他脱氢酶中一致的开放构象结合。激活剂ADP结合在活性中心附近，但与辅酶部位几乎没有重叠或完全不重叠。
