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Kinetics, energetics and specificity of a general amino acid transporter from the ectomycorrhizal fungus Paxillus involutus

Chalot, Michel; Brun, Annick; Botton, Bernard and Söderström, Bengt LU (1996) In Microbiology 142. p.1749-1756
Abstract
The kinetics, energetics and specificity of a general amino acid transporter were studied in the ectomycorrhizal fungus Paxillus involutus (Batsch) Fr. The uptake of amino acids showed features characteristic of active transport. After correction for a non-mediated transport component, the kinetics of glutamate, glutamine, alanine and aspartate uptake measured over a wide concentration range followed the simple Michaelis-Menten saturation curves, The apparent K-m derived from the Eadie-Hofstee plots ranged from 7 mu M for alanine to 27 mu M for glutamate, Dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone and NaN3 strongly inhibited amino acid uptake, whereas dicyclohexylcarbodiimide. vanadate and the ionophores monensin and nonactin... (More)
The kinetics, energetics and specificity of a general amino acid transporter were studied in the ectomycorrhizal fungus Paxillus involutus (Batsch) Fr. The uptake of amino acids showed features characteristic of active transport. After correction for a non-mediated transport component, the kinetics of glutamate, glutamine, alanine and aspartate uptake measured over a wide concentration range followed the simple Michaelis-Menten saturation curves, The apparent K-m derived from the Eadie-Hofstee plots ranged from 7 mu M for alanine to 27 mu M for glutamate, Dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone and NaN3 strongly inhibited amino acid uptake, whereas dicyclohexylcarbodiimide. vanadate and the ionophores monensin and nonactin had no effect on the uptake. Both ph dependence and inhibition by protonophores are consistent with a proton symport mechanism for amino acid uptake by P. involutus, Competition studies indicated a broad substrate recognition by the uptake system, which resembles the general amino acid permease of yeast, Dixon plots of the inhibition of glutamate uptake by alanine, lysine and methionine sulfoximine showed that inhibitions were competitive, Tire physiological importance of this transporter for the exchange of nitrogenous compounds between fungal and host plant cells in ectomycorrhizal associations is discussed. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
keywords
amino acid uptake, competition and inhibition experiments, ectomycorrhizal fungus, proton symport mechanism, Paxillus involutus
in
Microbiology
volume
142
pages
1749 - 1756
publisher
MAIK Nauka/Interperiodica
external identifiers
  • scopus:0029948761
ISSN
1465-2080
DOI
10.1099/13500872-142-7-1749
language
English
LU publication?
yes
id
cfa3472f-c370-4bed-8f7a-fff3bf116f2d (old id 2226268)
date added to LUP
2012-01-13 13:00:38
date last changed
2017-08-27 04:14:08
@article{cfa3472f-c370-4bed-8f7a-fff3bf116f2d,
  abstract     = {The kinetics, energetics and specificity of a general amino acid transporter were studied in the ectomycorrhizal fungus Paxillus involutus (Batsch) Fr. The uptake of amino acids showed features characteristic of active transport. After correction for a non-mediated transport component, the kinetics of glutamate, glutamine, alanine and aspartate uptake measured over a wide concentration range followed the simple Michaelis-Menten saturation curves, The apparent K-m derived from the Eadie-Hofstee plots ranged from 7 mu M for alanine to 27 mu M for glutamate, Dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone and NaN3 strongly inhibited amino acid uptake, whereas dicyclohexylcarbodiimide. vanadate and the ionophores monensin and nonactin had no effect on the uptake. Both ph dependence and inhibition by protonophores are consistent with a proton symport mechanism for amino acid uptake by P. involutus, Competition studies indicated a broad substrate recognition by the uptake system, which resembles the general amino acid permease of yeast, Dixon plots of the inhibition of glutamate uptake by alanine, lysine and methionine sulfoximine showed that inhibitions were competitive, Tire physiological importance of this transporter for the exchange of nitrogenous compounds between fungal and host plant cells in ectomycorrhizal associations is discussed.},
  author       = {Chalot, Michel and Brun, Annick and Botton, Bernard and Söderström, Bengt},
  issn         = {1465-2080},
  keyword      = {amino acid uptake,competition and inhibition experiments,ectomycorrhizal fungus,proton symport mechanism,Paxillus involutus},
  language     = {eng},
  pages        = {1749--1756},
  publisher    = {MAIK Nauka/Interperiodica},
  series       = {Microbiology},
  title        = {Kinetics, energetics and specificity of a general amino acid transporter from the ectomycorrhizal fungus Paxillus involutus},
  url          = {http://dx.doi.org/10.1099/13500872-142-7-1749},
  volume       = {142},
  year         = {1996},
}