Channel‐mediated permeation of ammonia gas through the peribacteroid membrane of soybean nodules

FEBS Letters

Tyerman, Stephen D¹  Niemietz, Christa M¹ 

[1] School of Biological Sciences, The Flinders University of South Australia, G.P.O. Box 2100, Adelaide, S.A. 5001, Australia

关键词: Peribacteroid membrane;    NH3 permeability;    Aquaporin;    Activation energy;    Mercury inhibition;    Nodulin 26;   

DOI  :  10.1016/S0014-5793(99)01729-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ammonia permeability of the peribacteroid membrane (PBM) from N₂-fixing soybean nodules was measured (8×10⁻⁵ m/s) using isolated PBM in a stopped-flow spectrofluorimeter. Ammonia (NH₃) uptake into PBM vesicles was inhibited by up to 42% by HgCl₂ (EC₅₀=2.9 μM, mercaptoethanol-reversible) and reduced by ATP pre-incubation. The activation energy of NH₃ uptake (52 kJ/mol) increased (118 kJ/mol) with HgCl₂. Water transport was also HgCl₂-sensitive (EC₅₀=52.6 μM), but increased by ATP pre-incubation. NH₃ and H₂O may permeate via different pathways through Nodulin 26 or there is another protein on the PBM that is permeable to NH₃.

【 授权许可】

Unknown