| Title | 암모니아와 glutamine에 의한 rhodopseudomonas sphaeroides의 질소 고정 효소활성에 미치는 methionine sulfoximine의 영향 | ||
| Author | 이혜주 | ||
| Address | 동아대학교 자연과학대학 생물학과 | ||
| Bibliography | Korean Journal of Microbiology, 26(3),215-222, 1988 | ||
| DOI | |||
| Key Words | Rhodopseydomonas sphaeroides, nitrogenase switch0off, methionine sufoximine, glutamine synthetase | ||
| Abstract | The effect of ammonia and glutamine on nitrogenase activity of Rhodopseudomonas sphaeroides was examined. The nitrogenase activity of this strain was inhibited by ammonia and glutamine. When ammonia and glutamine were exhausted, nitrogenase activity promptly resumed at its original rate. Methionine sulfoximine (MSX), irreversible glutamine synthetase (GS) inhibitor, is a structural analogue of glutamate. MSX was used in order to know whether the nitrogenase activity was inhibited by ammonia and glutamine directly or not. The ability of MSX to prevent nitrogenase switch-off by ammonia was found to be dependent upon the phase of culture. When the cells were sampled after 12 hour culture, 500uM MSX would not prevent the nitrogenase switch-off by ammonia. Twenty one percents of GS activity was inhibited by 500uM of MSX and concentration of released ammonia decreased. But nitrogenase activity was still inhibited by ammonia. However, nitrogenase switch-off after 20 hours would be prevented by 100uM of MSX. On the other hand, GS activity was ingibited completely by 100uM MSX and concentration of released ammonia somewhat increased. But nitrogenase activity was not inhibited. The data indicated that the inhibition of in vivo nitrogenase activity of Rp. sphaeroides by ammonia seemed to be mediated by products of ammonia assimilation rather than by ammonia itself. | ||
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