THE REACTION OF COENZYME PQQ WITH HYDRAZINES
THE REACTION OF COENZYME PQQ WITH HYDRAZINES
复制标题
DOI：
10.1039/p29900000315
复制
发表时间：
1990-02-01
期刊：
影响因子：
--
通讯作者：
OHSHIRO, Y
中科院分区：
文献类型：
--
作者：
MURE, M;NII, K;OHSHIRO, Y
辅酶PQQ与肼的反应，这是已知的醌蛋白胺氧化酶的抑制剂，已在体外进行了研究。在与苯肼、甲基肼、N，N-二甲基肼和N，N′-二甲基肼的反应中仅观察到氧化还原反应。然而，PQQ加合物的形成伴随着与4-硝基苯肼的反应发生，并且在与2，4-二硝基苯肼的反应中仅观察到腙的形成[分别为（3）和（4）]。动力学研究表明，氧化还原反应活性的大小顺序为苯肼、N，N′-二甲基肼、N，N-二甲基肼，与肼的二电子氧化还原电位无关。PQQ模型化合物[PQQ、PQQTME和（5）-（10）]在甲基肼氧化中的反应性也被检查，相对反应性似乎与醌官能团对亲核加成（水合）的反应性有关，但不反映双电子氧化还原电位。这些结果表明，PQQ与肼的还原是通过肼与醌的共价加成形成甲醇胺型中间体，然后电子从肼的氮流入醌部分来进行的。
The reaction of coenzyme PQQ with hydrazines, which are known to be inhibitors of quinoprotein amine oxidases, has been investigated in vitro. Only the redox reaction is observed in the reaction with phenylhydrazine, methylhydrazine,N,N-dimethylhydrazine, and N, N′-dimethylhydrazine. However, the PQQ adduct formation occurs concomitantly in the reaction with 4-nitrophenylhydrazine, and only hydrazone formation is observed in the reaction with 2,4-dinitrophenylhydrazine [(3) and (4), respectively]. Kinetic studies reveal that the order of the redox reactivity is phenylhydrazine ≃ methylhydrazine > N, N′-dimethylhydrazine N,N-dimethylhydrazine, which does not correlate with the two-electron redox potentials of these hydrazines. The reactivity of the PQQ model compounds [PQQ, PQQTME, and (5)–(10)] in the oxidation of methylhydrazine is also examined, the relative reactivity seems to be related to the reactivity of the quinone functional group toward nucleophilic addition (hydration), but does not reflect the two-electron redox potentials. These results suggest that reduction of PQQ with hydrazines proceeds via covalent addition of hydrazines to the quinone to form a carbinolamine type intermediate followed by electron flow from the nitrogen of hydrazines into the quinone moiety.