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Increase of Na+ gradient-dependent L-glutamate and L-aspartate transport in high K+ dog erythrocytes associated with high activity of (Na+, K+)-ATPase.
Title: | Increase of Na+ gradient-dependent L-glutamate and L-aspartate transport in high K+ dog erythrocytes associated with high activity of (Na+, K+)-ATPase. |
Authors: | Inaba, Mutsumi Browse this author →KAKEN DB | Maede, Yoshimitsu Browse this author →KAKEN DB |
Issue Date: | 10-Jan-1984 |
Publisher: | American Society for Biochemistry and Molecular Biology |
Journal Title: | The Journal of biological chemistry |
Volume: | 259 |
Issue: | 1 |
Start Page: | 312 |
End Page: | 317 |
PMID: | 6142884 |
Abstract: | As reported previously, some dogs possess red cells characterized by low Na+, high K+ concentrations, and high activity of (Na+, K+)-ATPase, although normal dog red cells contain low K+, high Na+, and lack (Na+, K+)-ATPase. Furthermore, these red cells show increased activities of L-glutamate and L-aspartate transport, resulting in high accumulations of such amino acids in their cells. The present study demonstrated: (i) Na+ gradient-dependent L-glutamate and L-aspartate transport in the high K+ and low K+ red cells were dominated by a saturable component obeying Michaelis-Menten kinetics. Although no difference of the Km values was observed between the high K+ and low K+ cells, the Vmax values for both amino acids' transport in the high K+ cells were about three times those of low ones. (ii) L- and D-aspartate, but not D-glutamate, competitively inhibited L-glutamate transport in both types of the cells. (iii) Ouabain decreased the uptake of the amino acids in the high K+ dog red cells, whereas it was not effective on those in the low K+ cells. (iv) The ATP-treated high K+ cells [(K+]i not equal to [K+]o, [Na+]i greater than [Na+]o) showed a marked decrease of both amino acids' uptake rate, which was almost the same as that of the low K+ cells. (v) Valinomycin stimulated the amino acids' transport in both of the high K+ and the ATP-treated low K+ cells [( K+]i greater than [K+]o, [Na+]o), suggesting that the transport system of L-glutamate and L-aspartate in both types of the cells might be electrogenic. These results indicate that the increased transport activity in the high K+ dog red cells was a secondary consequence of the Na+ concentration gradient created by (Na+, K+)-ATPase. |
Relation: | http://www.jbc.org/content/259/1/312 |
Type: | article |
URI: | http://hdl.handle.net/2115/73326 |
Appears in Collections: | 獣医学院・獣医学研究院 (Graduate School of Veterinary Medicine / Faculty of Veterinary Medicine) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 前出 吉光
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