Subramanian S, Ross J B, Ross P D, Brand L
Biochemistry. 1981 Jul 7;20(14):4086-93. doi: 10.1021/bi00517a022.
The difference spectra of binary and ternary complexes of horse liver alcohol dehydrogenase with oxidized and reduced nicotinamide adenine dinucleotides, nicotinamide 1,N6-ethenoadenine dinucleotide, and adenosine diphosphate ribose along with a number of substrate analogues have been measured. These spectra bear a very close resemblance to those obtained by perturbation of the coenzyme(s) and their analogues by acid, NaCl, dioxane, or tert-butyl alcohol. It is inferred that the coenzymes experience a combination of ionic and nonpolar environments at the adenine binding site of the enzyme. This is borne out by published X-ray crystallographic results. The phosphorescence spectra do not indicate the presence of ionized tyrosine in ternary complexes invovling enzyme, coenzyme, and substrate analogues. The ultraviolet spectra can be explained as arising from the perturbation of the coenzyme chromophores upon binding to the enzyme without having to invoke tyrosine ionization.
已测量了马肝醇脱氢酶与氧化型和还原型烟酰胺腺嘌呤二核苷酸、烟酰胺1,N6-乙烯腺嘌呤二核苷酸、二磷酸腺苷核糖以及多种底物类似物形成的二元和三元复合物的差光谱。这些光谱与通过酸、氯化钠、二氧六环或叔丁醇对辅酶及其类似物进行扰动所获得的光谱非常相似。据推断，辅酶在酶的腺嘌呤结合位点经历了离子和非极性环境的组合。已发表的X射线晶体学结果证实了这一点。磷光光谱并未表明在涉及酶、辅酶和底物类似物的三元复合物中存在离子化的酪氨酸。紫外光谱可以解释为是由于辅酶发色团与酶结合时受到扰动而产生的，无需涉及酪氨酸离子化。
