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

FEBS Lett. 2000 Jan 14;465(2-3):110-4. doi: 10.1016/s0014-5793(99)01729-9.

Abstract

Ammonia permeability of the peribacteroid membrane (PBM) from N(2)-fixing soybean nodules was measured (8x10(-5) m/s) using isolated PBM in a stopped-flow spectrofluorimeter. Ammonia (NH(3)) uptake into PBM vesicles was inhibited by up to 42% by HgCl(2) (EC(50)=2.9 microM, mercaptoethanol-reversible) and reduced by ATP pre-incubation. The activation energy of NH(3) uptake (52 kJ/mol) increased (118 kJ/mol) with HgCl(2). Water transport was also HgCl(2)-sensitive (EC(50)=52.6 microM), but increased by ATP pre-incubation. NH(3) and H(2)O may permeate via different pathways through Nodulin 26 or there is another protein on the PBM that is permeable to NH(3).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonia / metabolism*
  • Cell Membrane / metabolism
  • Ion Channels / metabolism*
  • Mercuric Chloride / metabolism
  • Permeability
  • Soybeans / metabolism*
  • Water / metabolism

Substances

  • Ion Channels
  • Water
  • Mercuric Chloride
  • Ammonia