Premium
Channel‐mediated permeation of ammonia gas through the peribacteroid membrane of soybean nodules
Author(s) -
Niemietz Christa M,
Tyerman Stephen D
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01729-9
Subject(s) - incubation , ammonia , chemistry , permeation , membrane , membrane transport , permeability (electromagnetism) , biochemistry , mole , chromatography , nuclear chemistry , biophysics , biology
Ammonia permeability of the peribacteroid membrane (PBM) from N 2 ‐fixing soybean nodules was measured (8×10 −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 μM, 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 μM), 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 .