Cytochrome P450-catalyzed dealkylation of atrazine by<i>Rhodococcus</i>sp. strain NI86/21 involves hydrogen atom transfer rather than single electron transfer
作者:Armin H. Meyer、Agnieszka Dybala-Defratyka、Peter J. Alaimo、Inacrist Geronimo、Ariana D. Sanchez、Christopher J. Cramer、Martin Elsner
DOI:10.1039/c4dt00891j
日期:——
Cytochrome P450 enzymes are responsible for a multitude of natural transformation reactions. For oxidative N-dealkylation, single electron (SET) and hydrogen atom abstraction (HAT) have been debated as underlying mechanisms. Combined evidence from (i) product distribution and (ii) isotope effects indicate that HAT, rather than SET, initiates N-dealkylation of atrazine to desethyl- and desisopropylatrazine
细胞色素P450酶负责多种自然转化反应。对于氧化性N-脱烷基反应,单电子(SET)和氢原子抽象(HAT)已被讨论为潜在的机制。来自(i)产品分布和(ii)同位素效应的综合证据表明,HAT而非SET通过微生物红球菌(Rhodococcus sp。)引发了r去津的N-去烷基化作用,形成了去乙基和去异丙基去去津。NI86 / 21株 (i)产物分析表明,在烷基链的αC和βC原子上均发生了非选择性氧化,这是自由基反应所期望的,但不是SET。(ii)正常的13 C和15 N以及明显的2 H同位素效应(ε碳:-4.0‰±0.2‰;ε氮:−1.4‰±0.3‰,KIE H:3.6±0.8)与HAT的计算值定性吻合,而SET预测有13 C和15 N同位素反作用。用Fe(IV)O模型系统[5,10,15,20-四(五氟苯基)卟啉-铁(III)-氯化物+ NaIO 4 ]观察到相似的结果,但用高锰酸盐观察不到。