Corrigall A V, Siziba K B, Maneli M H, Shephard E G, Ziman M, Dailey T A, Dailey H A, Kirsch R E, Meissner P N
MRC/UCT Liver Research Centre, University of Cape Town Medical School, Observatory, 7925, South Africa.
Arch Biochem Biophys. 1998 Oct 15;358(2):251-6. doi: 10.1006/abbi.1998.0834.
The previously cloned and expressed protoporphyrinogen oxidase from Bacillus subtilis has been purified to homogeneity by Ni2+ affinity chromatography using a His6 tag and characterized. The enzyme has a molecular weight of approximately 56,000 daltons, a pI of 7.5, a pH optimum (protoporphyrinogen) of 8.7, and a noncovalently bound flavine adenine dinucleotide cofactor. The Michaelis constants (Km) for protoporphyrinogen-IX, coproporphyrinogen-III, and mesoporphyrinogen-IX are 1.0, 5.29, and 4.92 microM, respectively. Polyclonal antibody to B. subtilis protoporphyrinogen oxidase demonstrated weak cross-reactivity with both human and Myxococcus xanthus protoporphyrinogen oxidase. B. subtilis protoporphyrinogen oxidase is not inhibited by the diphenyl ether herbicide acifluorfen at 100 microM and is weakly inhibited by methylacifluorfen at the same concentration. Bilirubin, biliverdin, and hemin are all competitive inhibitors of this enzyme.
先前从枯草芽孢杆菌中克隆并表达的原卟啉原氧化酶已通过使用His6标签的Ni2+亲和色谱法纯化至同质，并进行了表征。该酶的分子量约为56,000道尔顿，pI为7.5，最适pH（原卟啉原）为8.7，并且具有非共价结合的黄素腺嘌呤二核苷酸辅因子。原卟啉原-IX、粪卟啉原-III和中卟啉原-IX的米氏常数（Km）分别为1.0、5.29和4.92 microM。针对枯草芽孢杆菌原卟啉原氧化酶的多克隆抗体与人及黄色黏球菌原卟啉原氧化酶均表现出弱交叉反应性。枯草芽孢杆菌原卟啉原氧化酶在100 microM浓度下不受二苯醚除草剂三氟羧草醚的抑制，在相同浓度下受氟磺胺草醚的抑制作用较弱。胆红素、胆绿素和血红素均为该酶的竞争性抑制剂。
