Haddock J D, Nadim L M, Gibson D T
Department of Microbiology, University of Iowa, Iowa City 52242.
J Bacteriol. 1993 Jan;175(2):395-400. doi: 10.1128/jb.175.2.395-400.1993.
Pseudomonas sp. strain LB400 grows on biphenyl as the sole carbon and energy source. This organism also cooxidizes several chlorinated biphenyl congeners. Biphenyl dioxygenase activity in cell extract required addition of NAD(P)H as an electron donor for the conversion of biphenyl to cis-2,3-dihydroxy-2,3-dihydrobiphenyl. Incorporation of both atoms of molecular oxygen into the substrate was shown with 18O2. The nonlinear relationship between enzyme activity and protein concentration suggested that the enzyme is composed of multiple protein components. Ion-exchange chromatography of the cell extract gave three protein fractions that were required together to restore enzymatic activity. Similarities with other multicomponent aromatic hydrocarbon dioxygenases indicated that biphenyl dioxygenase may consist of a flavoprotein and iron-sulfur proteins that constitute a short electron transport chain involved in catalyzing the incorporation of both atoms of molecular oxygen into the aromatic ring.
假单胞菌属菌株LB400以联苯作为唯一的碳源和能源生长。该微生物还能共氧化几种氯代联苯同系物。细胞提取物中的联苯双加氧酶活性需要添加NAD(P)H作为电子供体，以便将联苯转化为顺式-2,3-二羟基-2,3-二氢联苯。用18O2证明了分子氧的两个原子都掺入了底物中。酶活性与蛋白质浓度之间的非线性关系表明该酶由多种蛋白质成分组成。细胞提取物的离子交换色谱法得到了三个蛋白质组分，它们共同作用才能恢复酶活性。与其他多组分芳烃双加氧酶的相似性表明，联苯双加氧酶可能由一种黄素蛋白和铁硫蛋白组成，它们构成了一个短电子传递链，参与催化分子氧的两个原子掺入芳香环。
