Dong X, Stams A J
Department of Microbiology, Wageningen Agricultural University, The Netherlands.
Antonie Van Leeuwenhoek. 1995;67(4):345-50. doi: 10.1007/BF00872933.
Cell-free extracts of crotonate-grown cells of the syntrophic butyrate-oxidizing bacterium Syntrophospora bryantii contained high hydrogenase activities (8.5-75.8 mumol.min-1mg-1 protein) and relatively low formate dehydrogenase activities (0.04-0.07 mumol.min-1 mg-1 protein). The KM value and threshold value of the hydrogenase for H2 were 0.21 mM and 18 microM, respectively, whereas the KM value and threshold value of the formate dehydrogenase for formate were 0.22 mM and 10 microM, respectively. Hydrogenase, butyryl-CoA dehydrogenase and 3-OH-butyryl-CoA dehydrogenase were detected in the cytoplasmic fraction. Formate dehydrogenase and CO2 reductase were membrane-bound, likely located at the outer aspect of the cytoplasmic membrane. Results suggest that during syntrophic butyrate oxidation H2 is formed intracellularly while formate is formed at the outside of the cell.
以巴豆酸为碳源生长的互营丁酸氧化细菌布氏合成孢菌（Syntrophospora bryantii）的无细胞提取物具有较高的氢化酶活性（8.5 - 75.8 μmol·min⁻¹·mg⁻¹蛋白质）和相对较低的甲酸脱氢酶活性（0.04 - 0.07 μmol·min⁻¹·mg⁻¹蛋白质）。氢化酶对H₂的米氏常数（KM值）和阈值分别为0.21 mM和18 μM，而甲酸脱氢酶对甲酸的KM值和阈值分别为0.22 mM和10 μM。在细胞质组分中检测到了氢化酶、丁酰辅酶A脱氢酶和3-羟基丁酰辅酶A脱氢酶。甲酸脱氢酶和CO₂还原酶与膜结合，可能位于细胞质膜的外侧。结果表明，在互营丁酸氧化过程中，H₂在细胞内形成，而甲酸在细胞外形成。
