Adenosylcobinamide, the Base-Free Analog of Coenzyme B12 (Adenosylcobalamin). 1.1 Probing the Role of the Axial 5,6-Dimethylbenzimidazole Base in Coenzyme B12 via Exogenous Axial Base Kassociation, ΔH, and ΔS Measurements plus a Critical Review of the Relevant Biochemical Literature
Adenosylcobinamide, the Base-Free Analog of Coenzyme B12 (Adenosylcobalamin). 1.1 Probing the Role of the Axial 5,6-Dimethylbenzimidazole Base in Coenzyme B12 via Exogenous Axial Base Kassociation, ΔH, and ΔS Measurements plus a Critical Review of the Relevant Biochemical Literature
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腺苷钴酰胺，辅酶 B12 的无碱基类似物（腺苷钴胺素） 1.1 通过外源轴向碱基结合、ΔH 和 ΔS 测量以及相关生化文献的批判性回顾探讨辅酶 B12 中轴向 5,6-二甲基苯并咪唑碱基的作用。
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发表时间：
1996
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影响因子：
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通讯作者：
R. Finke
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作者：
C. Garr;and Jeanne M. Sirovatka;R. Finke
腺苷钴胺（AdoCbi+BF4-）是腺苷钴胺素（AdoCbl或辅酶B12）的无碱形式，已经用一系列14个外源α-轴碱基进行了研究。具体地说，测量了平衡缔合常数Kassoc作为温度的函数，从而得到了它们相关的ΔH和ΔS。所研究的碱基包括：(i)外源性1,5,6-三甲基苯并咪唑[类似于腺苷钴胺素分子内附加的5,6-二甲基苯并咪唑碱]；（ii）位阻磷化氢碱基（没有一种显示出可检测到的结合，这与对钴胺素B12 “模型”的研究形成鲜明对比）；(3)电子上给价越来越大，但等构的4-取代吡啶轴碱。目前Kassoc研究的总体趋势是两方面的：碱提供的电子越多，Kassoc越大，如果有的话，大的碱结合弱。本文还包含了现有的，非ado RCbi+轴基Kassoc文献的表格摘要加上…
Adenosylcobinamide (AdoCbi+BF4-), the base-free form of adenosylcobalamin (AdoCbl or coenzyme B12), has been studied with a series of 14 exogenous α-axial bases. Specifically, equilibrium association constants, Kassoc, as a function of temperature were measured, and thus their associated ΔH and ΔS were obtained. Bases studied include the following: (i) exogenous 1,5,6-trimethylbenzimidazole [analogous to adenosylcobalamin's intramolecularly appended 5,6-dimethylbenzimidazole base]; (ii) sterically encumbered phosphine bases (none of which showed detectable binding in dramatic contrast to studies of, for example, cobaloxime B12 “models”); and (iii) electronically increasingly donating, but isosteric, 4-substituted pyridine axial bases. The general trends from the present Kassoc studies are 2-fold: the more electron donating the base, the greater the Kassoc, and bulky bases bind weakly if at all. This paper also contains a tabular summary of the existing, non-Ado RCbi+ axial-base Kassoc literature plus th...