Laurinavichene T V, Tsygankov A A
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Oblast, 142290 Russia.
Mikrobiologiia. 2003 Nov-Dec;72(6):740-5.
The study of Escherichia coli mutants synthesizing either hydrogenase 1 (HDK203) or hydrogenase 2 (HDK103) showed that the nitrate-dependent uptake of hydrogen by E. coli cells can be accomplished through the action of either of these hydrogenases. The capability of the cells for hydrogen-dependent nitrate respiration was found to be dependent on the growth conditions. E. coli cells grown anaerobically without nitrate in the presence of glucose were potentially capable of nitrate-dependent hydrogen consumption. The cells grown anaerobically in the presence of nitrate exhibited a much lower capability for nitrate-dependent hydrogen consumption. The inhibitory effect of nitrate on this capability of bacterial cells was either weak (the mutant HDK203) or almost absent (the mutant HDK103) when the cells were grown in the presence of peptone and hydrogen. Hydrogen stimulated the growth of the wild-type strain and the mutant HDK103 (but not the mutant HDK203) cultivated in the medium with nitrate and peptone. These data suggest that hydrogenase 2 is much more active in catalyzing the nitrate-dependent hydrogen consumption than is hydrogenase 1.
对合成氢化酶1（HDK203）或氢化酶2（HDK103）的大肠杆菌突变体的研究表明，大肠杆菌细胞对硝酸盐依赖的氢气摄取可通过这两种氢化酶中的任何一种来实现。发现细胞进行氢气依赖的硝酸盐呼吸的能力取决于生长条件。在葡萄糖存在下无氧生长的大肠杆菌细胞有进行硝酸盐依赖的氢气消耗的潜在能力。在硝酸盐存在下无氧生长的细胞表现出较低的硝酸盐依赖的氢气消耗能力。当细胞在蛋白胨和氢气存在下生长时，硝酸盐对细菌细胞这种能力的抑制作用要么较弱（突变体HDK203），要么几乎不存在（突变体HDK103）。氢气刺激了在含有硝酸盐和蛋白胨的培养基中培养的野生型菌株和突变体HDK103（但不包括突变体HDK203）的生长。这些数据表明，氢化酶2在催化硝酸盐依赖的氢气消耗方面比氢化酶1更具活性。
