Ansell R J, Small D A, Lowe C R
Institut für Analytische Chemie, Chemo- und Biosensorik, Universität Regensburg, 93 053 Regensburg, Germany.
J Mol Recognit. 1999 Jan-Feb;12(1):45-56. doi: 10.1002/(SICI)1099-1352(199901/02)12:1<45::AID-JMR374>3.0.CO;2-9.
We have previously shown that a range of nicotinamide containing 'biomimetic coenzymes' function as active analogues of NAD+ in the oxidation of alcohols by horse liver alcohol dehydrogenase (HLADH), despite their apparently astonishing lack of structural similarity to the natural coenzyme. The simplest structure as yet shown to exhibit activity is the biomimetic coenzyme CL4. To investigate the effect of the structure of this truncated artificial coenzyme on its activity, a range of close structural analogues of CL4 were designed, synthesized and characterized. The electrochemical reduction potentials of the analogues were strongly influenced by the nature of the groups attached to the pyridine ring. All of the analogues could be chemically reduced using sodium borohydride, to give compounds with altered UV-visible absorption and fluorescence properties. An HPLC-based assay suggested that two of the new analogues were coenzymically active in the oxidation of butan-1-ol by HLADH, with one displaying a significantly higher activity than CL4. The results demonstrate which features of the structures of the coenzymes lead to desirable electrochemical and spectroscopic properties, but suggest that the structural requirements for a functional coenzyme are quite stringent. These observations may be used to design an artificial coenzyme which combines the best features of those studied so far.
我们之前已经表明，一系列含烟酰胺的“仿生辅酶”在马肝醇脱氢酶（HLADH）催化醇类氧化反应中可作为NAD+的活性类似物发挥作用，尽管它们与天然辅酶在结构上明显缺乏相似性，令人惊讶。目前已证明具有活性的最简单结构是仿生辅酶CL4。为了研究这种截短的人工辅酶结构对其活性的影响，设计、合成并表征了一系列CL4的紧密结构类似物。这些类似物的电化学还原电位受吡啶环上连接基团性质的强烈影响。所有类似物都可用硼氢化钠进行化学还原，得到具有改变的紫外可见吸收和荧光性质的化合物。基于高效液相色谱的分析表明，其中两种新类似物在HLADH催化1-丁醇氧化反应中具有辅酶活性，其中一种的活性明显高于CL4。结果表明了辅酶结构的哪些特征导致了理想的电化学和光谱性质，但也表明功能性辅酶的结构要求相当严格。这些观察结果可用于设计一种结合了迄今为止所研究辅酶最佳特性的人工辅酶。
