Heyes D J, Martin G E, Reid R J, Hunter C N, Wilks H M
Krebs Institute for Biomolecular Research and Robert Hill Institute for Photosynthesis, Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN, Sheffield, UK.
FEBS Lett. 2000 Oct 13;483(1):47-51. doi: 10.1016/s0014-5793(00)02081-0.
protochlorophyllide oxidoreductase (POR) catalyses the light-dependent reduction of protochlorophyllide to chlorophyllide, a key regulatory reaction in the chlorophyll biosynthetic pathway. POR from the cyanobacterium Synechocystis has been overproduced in Escherichia coli with a hexahistidine tag at the N-terminus. This enzyme (His(6)-POR) has been purified to homogeneity and a preliminary characterisation of its kinetic and substrate binding properties is presented. Chemical modification experiments have been used to demonstrate inhibition of POR activity by the thiol-specific reagent N-ethyl maleimide. Substrate protection experiments reveal that the modified Cys residues are involved in either substrate binding or catalysis.
原叶绿素酸酯氧化还原酶（POR）催化原叶绿素酸酯光依赖性还原为叶绿素酸酯，这是叶绿素生物合成途径中的关键调控反应。来自集胞藻的POR已在大肠杆菌中过量表达，其N端带有六聚组氨酸标签。该酶（His(6)-POR）已纯化至同质，并对其动力学和底物结合特性进行了初步表征。化学修饰实验已用于证明硫醇特异性试剂N-乙基马来酰亚胺对POR活性的抑制作用。底物保护实验表明，修饰的半胱氨酸残基参与底物结合或催化。
