Channel-mediated permeation of ammonia gas through the peribacteroid membrane of soybean nodules |
| |
Authors: | Niemietz C M Tyerman S D |
| |
Institution: | School of Biological Sciences, The Flinders University of South Australia, G.P.O. Box 2100, Adelaide, S.A., Australia. |
| |
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). |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|