A Study on Nitrogenase - Mediated Evolution of Molecular Hydrogen in Rhodopseudomonas sphaeroides K-7

Rhodopseudomonas sphaeroides K-7 의 질소고정 효소 의존성 수소생성에 관한 연구

  • Lee, Jeong-Kug (Applied Microbiology Laboratory, Korea Advanced Institute of Science and Technology) ;
  • Moo Bae (Department of Biology, Ewha Women′s University)
  • Published : 1983.09.01


Rhodopseudomonas sphaeroides K-7 evolves large quantities of molecular hydrogen under anaerobic and light illuminated conditions in the presence of utilizable organic compounds as electron donors. Photoevolution of molecular hydrogen was strictly dependent on light as the activity of nitrogenase in this organism. Both of these were inhibited to the nearly same extent at varying concentrations of ammonium ion which also depressed nitrogenase synthesis. In the reaction mixtures devoid of molybdenum ion which is known as the component of nitrogenase, hydrogen evolution also decreased similarly like nitrogenase activity. Photoevolution of molecular hydrogen appeared to have no relationship with hydrogenase activity and bacteriocholophyll content and it was markedly inhibited under the atmosphere of $C_2$H$_2$, $N_2$ or $O_2$. The results strongly indicate that hydrogen evolution by R. sphaeroides K-7 might be catalyzed by nitrogenase. Both hydrogen evolution and nitrogenase activity were largely influenced by the nutritional history of the resting cells. From which we propose that glutamate might play an important role in the regulation of nigrogenase activity in vivo.