Oct 1, 1970

Effects of monovalent cations on the sodium-alanine interaction in rabbit ileum. Implication of anionic groups in sodium binding

The Journal of General Physiology
R A Frizzell, S G Schultz

Abstract

H, K, Rb, and Li inhibit Na-dependent alanine influx across the brush border of rabbit ileum. Kinetic analysis indicates that H and K behave as competitive inhibitors of influx so that increasing the concentration of H or K in the mucosal solution is kinetically indistinguishable from decreasing the Na concentration. In addition the coupling between alanine and Na influxes is markedly reduced at pH 2.5. With the exception of H and Li, none of these monovalent cations significantly affects carrier-mediated alanine influx in the absence of Na indicating that their inhibitory effects are largely restricted to the Na-dependent fraction of influx. Increasing H concentration from 0.03 to 3 mM does not affect influx in the absence of Na but markedly inhibits influx in the presence of Na. Li significantly enhances alanine influx in the absence of Na. Ag, UO(2), and La also inhibit the Na-dependent fraction of alanine influx. These findings suggest that anionic groups having a pK(a) of approximately 4 are involved in the interaction between Na and the alanine-carrier complex; present evidence implicates carboxylate groups however, phosphoryl residues cannot be ruled out. The previously proposed kinetic model for the Na-alanine interacti...Continue Reading

  • References28
  • Citations11

References

  • References28
  • Citations11

Citations

Mentioned in this Paper

Potassium
Ileum
Ions
Brush border antigen
Abufne
Structure of Intestinal Gland
Rubidium
Tritium
Chinchilla Rabbits
Entire Ileum

About this Paper

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