On the mechanism of porphobilinogen deaminase. Design, synthesis, and enzymatic reactions of novel porphobilinogen analogs.
作者:Clotilde Pichon、Karen R. Clemens、Alan R. Jacobson、A. Ian Scott
DOI:10.1016/s0040-4020(01)81567-2
日期:1992.6
Three new derivatives of porphobilinogen (PBG;1) were designed and synthesized to study the mechanism of ammonia loss during the tetramerization of PBG, catalyzed by the enzyme PBG deaminase. Two of these compounds are substituted at the C-11 carbon with CH3 or CF3, while the third analog is the N-methyl derivative of PBG wherein the pyrrole proton is replaced with methyl. All three compounds reacted
设计并合成了三种新的胆色素原(PBG; 1)衍生物,以研究PBG脱氨酶催化的PBG四聚反应过程中氨损失的机理。这些化合物中的两个在C-11碳上被CH 3或CF 3取代,而第三个类似物是PBG的N-甲基衍生物,其中吡咯质子被甲基取代。这三种化合物都与PBG脱氨酶反应至不同程度的完成。我们的结果表明,尽管目前尚不确定亲电子试剂的实际结构,但通过酶激活底物涉及一种在C-11碳上具有大量正电荷的中间体。除了定义最初形成的亲电试剂的性质外,我们的研究结果还揭示了有关酶活性位点亲核物种的性质。这三种新的吡咯的结果可能暗示了通过E1型途径进行的第一个已知的酶促脱氨反应。