Finke R G, Martin B D
Department of Chemistry, University of Oregon, Eugene 97403-1253.
J Inorg Biochem. 1990 Sep;40(1):19-22. doi: 10.1016/0162-0134(90)80036-w.
Comparison of the 25 degrees C Co-C bond homolysis rate constant of adenosyl-cobalamin (coenzyme B12) vs that for electrochemically reduced adenosyl-cobalamin radical anion indicates a rate enhancement of at least 10(12 +/- 2) upon the addition of one antibonding electron. Even though electrochemical reduction promotes Co-C homolysis by virtually the same amount as the 10(12 +/- 1) enzymic activation seen for adenosylcobalamin, electron-transfer activation of the Co-C homolysis in adenosylcobalamin-dependent enzyme reactions is considered unlikely, based on four lines of evidence.
将腺苷钴胺素（辅酶B12）在25摄氏度下的Co-C键均裂速率常数与电化学还原的腺苷钴胺素自由基阴离子的该速率常数进行比较，结果表明，添加一个反键电子后，速率提高了至少10(12±2) 。尽管电化学还原促进Co-C均裂的程度与腺苷钴胺素的10(12±1)酶促活化几乎相同，但基于四条证据线，腺苷钴胺素依赖性酶反应中Co-C均裂的电子转移活化被认为不太可能。
