Dicarboxylic amino acid influx across brush border of rabbit ileum. Effects of amino acid charge on the sodium-amino acid interaction.
TLDR
Comparison of the kinetic parameters for anionic, neutral, and cationic amino acids suggests that amino acid charge influences the stability of the binary (amino acid-site) complex and the affinity of this binary complex for the subsequent binding of Na.Abstract:
Glutamate and aspartate influxes across the brush border of rabbit intestine are saturable processes that are subject to competitive inhibition and are markedly influenced by the Na concentration in the mucosal solution. Lowering the Na concentration increases the amino acid concentration needed to elicit a half-maximal influx but does not significantly affect the maximal influx. The interaction between Na and anionic amino acid influx can be described by the same kinetic model that has been applied to the influxes of neutral amino acids and lysine. Comparison of the kinetic parameters for anionic, neutral, and cationic amino acids suggests that amino acid charge influences (a) the stability of the binary (amino acid-site) complex and (b) the affinity of this binary complex for the subsequent binding of Na. A mechanistic interpretation of these interactions is proposed.read more
Citations
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Amino acid transport across mammalian intestinal and renal epithelia.
TL;DR: The identification of most epithelial amino acid transporters over the past 15 years allows the definition of these disorders at the molecular level and provides a clear picture of the functional cooperation between transporter in the apical and basolateral membranes of mammalian epithelial cells.
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High affinity uptake systems for glycine, glutamic and aspartic acids in synaptosomes of rat central nervous tissues
TL;DR: The uptakes of glutamic and aspartic acids were mutually competitive in both cerebral cortical and spinal cord preparations, suggesting that they utilize the same uptake mechanism.
Journal ArticleDOI
Studies on the Electrical Potential Profile across Rabbit Ileum Effects of sugars and amino acids on transmural and transmucosal electrical potential differences
TL;DR: It appears that the Na influx that is coupled to the influxes of amino acids and sugars is electrogenic and responsible for the depolarization of ψmc, which is seen in tissues poisoned with metabolic inhibitors or ouabain.
Journal ArticleDOI
Protein digestion and absorption.
Gary M. Gray,Herbert L. Cooper +1 more
TL;DR: Conditionally essential amino acids are typically present, but in certain conditions may be deficient and an example is found in the disease phenylketonuria (PKU).
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Metabolism of absorbed aspartate, asparagine, and arginine by rat small intestine in vivo
TL;DR: Catabolism of several amino acids from the lumen plus glutamine from arterial blood may provide an important energy source in small intestine.
References
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Journal ArticleDOI
Alanine and Sodium Fluxes Across Mucosal Border of Rabbit Ileum
TL;DR: Evidence is presented that Na transport across the mucosal border cannot be attributed to simple diffusion even though the net flux across this surface is in the direction of the electrochemical potential difference.
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Autoradiographic study of sugar and amino acid absorption by everted sacs of hamster intestine.
TL;DR: Autoradiographs were prepared from frozen sections of everted sacs of hamster jejunum which had been incubated in vitro with C14- or H3-labeled sugars and amino acids, inferring that active transport systems for sugars and Amino acids reside in the brush border region of the cell.
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Sodium and Sugar Fluxes across the Mucosal Border of Rabbit Ileum
TL;DR: A model has been developed for the sugar transport system involving a transport site that combines with both sugar and Na and there appeared to be little mediated entry of 3 MG into the cells from Na-free solution.
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Kinetic Relations of the Na-Amino Acid Interaction at the Mucosal Border of Intestine
TL;DR: The hypothesis that interactions between Na and amino acid transport depend in part on a common entry mechanism at the mucosal border of the intestine is supported.