摘要
报道了某些双齿配体对固氮酶促反应影响的研究结果．发现１，２－双（二苯基磷）－乙烷（ＤＰＰＥ）对固氮酶酶促乙炔还原反应有促进作用，但同时又抑制了固氮酶的放氢反应。而比ＤＰＰＥ少一个－ＣＨ２－链的双（二苯基磷）－甲烷（ＤＰＰＭ）却不能表现出对固氮酶促乙炔还原活力的促进作用．对照固氮酶ＭｏＦｅ－蛋白Ｘ－光衍射结构分析结果和量子化学近似计算所导出的固氮酶活性中心结构模型提出了ＤＰＰＥ促进酶促乙炔还原反应的一种可能的解释．
In previous work from this laboratory,nitrogenase substrates of about a dozen known types were regarded as chemical probes,and multinuclear coordination activation of the exogenous substrates by cubane-like,or twin-cubane-like cluster structural active-center was inferred.Recent publications of models of nitrogenase M-cluster and P-clusters by Bolin and Rees et al,based upon single-crystal Xray diffraction data with 0.28 and 0.22 nm resolution,have shed new light on the structure of nitrogenase active center.In the present work,we aim to gain information from new chemical probes which alter the substrate specificities(N2,acetylene,or proton reduction etc)of nitrogenase,It will be very useful in examining and understanding the structure and function of the latest proposed model of nitrogenase active center.The behaviors of 1,2-bis(diphenylphosphino)ethane,a promoter of in vitro nitrogenasc catalyzed acetylene reductive hydrogenation,but an inhibitor of hydrogen evolution reaction, as a new chemical probe of nitrogenase active center are reported,together with more detailed study on the behaviors of o-phthalaldehyde as a potent inhibitor of nitrogenase activity.The preliminary data we had acquired are consistent with the hypothesis of the two-site model of H2 evolution in nitrogenase MoFe-protein.Furthermore,in addition to the M-cluster,P-cluster is probably involved in the second site of H2 evolution,Further information provided by this work indicate that the functions of M-& P-clusters in nitrogenase catalyzed N2 reduction reactivity may be different from that of acetylene reduction,for example, N2 redution to NH3 needs assistance of Mo,whereas acetylene reduction does not.
出处
《分子催化》
EI
CAS
CSCD
1994年第2期81-85,共5页
Journal of Molecular Catalysis(China)
基金
国家基础性研究重大关键项目
人事部专家司博士后经费资助
关键词
固氮酶
双齿配体
固氮
活性
酶
Nitrogenase,Bidentate ligands,Promoter,Inhibitor.
