CHARACTERISTICS OF ACIDIC AMINO ACID TRANSPORT IN MAMMALIAN KIDNEY

A series of clearance experiments on dogs were carried out which were designed to confirm and characterize the renal tubular reabsorption of glutamic and aspartic acids. Tubular reabsorption was measured and found to reach a maximum of about 100 μmole/minute for L-glutamic and L-aspartic acids and a slightly lower level for D-aspartic. Competitive studies using substituted amino acids were performed and three patterns of inhibition of amino acid reabsorption observed. Acidic amino acids inhibited the reabsorption of each other, while neutral amino acids (and an acidic amino acid substituted so as to have a neutral side chain) inhibited the reabsorption of a wide range of other amino acids. Compounds with the amino group or either carboxyl group substituted or absent, but not resembling neutral amino acids, were not inhibitory. There appears to be a specialized mechanism for acidic amino acid transport which probably requires all three functional groups but which may be interfered with by a compound with alpha carboxyl and amino groups and a neutral side chain.

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Interactions of neutral and acidic amino acids in renal tubular transport

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1962.202.3.577 ◽

1962 ◽

Vol 202 (3) ◽

pp. 577-583 ◽

Cited By ~ 44

Author(s):

William A. Webber

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Plasma Concentrations ◽

Side Chain ◽

Neutral Amino Acids ◽

Acidic Amino Acids ◽

Renal Tubular Reabsorption ◽

Renal Tubular Transport ◽

Renal Tubular ◽

Amino Acid Concentrations

The effects of intravenous infusions of a variety of neutral and acidic amino acids on the plasma concentrations and excretions of naturally occurring amino acids were studied in dogs. Conventional clearance techniques were used, and the amino acid concentrations were determined by ion exchange column chromatography. Infusion of either l-glutamic acid or l-aspartic acid caused a gross increase in the plasma concentration and excretion of the other. Infusions of neutral amino acids including glycine, l-alanine, l-leucine, l-methionine, l-proline, and l-phenylalanine caused some minor changes in the endogenous plasma amino acid concentrations. They produced increases in the excretion of other neutral amino acids and, in some cases, of acidic and basic amino acids as well. In general, amino acids with long side chains were most effective in inhibiting reabsorption while cyclic side-chain compounds were less effective. There appear to be at least three somewhat separable mechanisms for renal tubular reabsorption of amino acids in dogs.

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Amino acid transport systems in intestinal brush-border membranes from lepidopteran larvae

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1989.257.3.r494 ◽

1989 ◽

Vol 257 (3) ◽

pp. R494-R500 ◽

Cited By ~ 1

Author(s):

B. Giordana ◽

V. F. Sacchi ◽

P. Parenti ◽

G. M. Hanozet

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Brush Border ◽

Amino Acid Transport ◽

Transport Systems ◽

Acid Transport ◽

Specific System ◽

Neutral Amino Acids ◽

Intestinal Brush Border ◽

Lepidopteran Larvae

Experiments with intestinal brush-border membrane vesicles from lepidopteran larvae disclosed the occurrence of unique cotransporter proteins that use K+ as the driver cation for the transmembrane transfer of amino acids across the luminal border of midgut enterocytes. Six apical membrane amino acid transport systems have been identified. These systems are 1) a neutral amino acid transporter with a broad spectrum of interactions with most neutral amino acids, which is highly concentrative, strongly K+- and electrical potential-dependent, poorly stereospecific, and recognizes histidine, but not proline, glycine, or alpha-(methylamino)isobutyric acid (MeAIB); 2) a specific system for L-proline; 3) a specific system for glycine with a higher affinity for Na+ than for K+; 4) a specific system for L-lysine, which is dependent on membrane potential, is highly sensitive to external K+, and does not interact with L-arginine or neutral amino acids; 5) a specific K+-dependent process for glutamic acid, which does not recognize aspartic acid; and last, 6) an apparently unique K+- driven mechanism for D-alanine, which is potential-dependent and strongly stereospecific.

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Intestinal Transport of Two Dipeptides Containing the Same Two Neutral Amino Acids in Man

Clinical Science ◽

10.1042/cs0450291 ◽

1973 ◽

Vol 45 (3) ◽

pp. 291-299 ◽

Cited By ~ 6

Author(s):

D. B. A. Silk ◽

D. Perrett ◽

M. L. Clark

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Transport System ◽

Amino Acid Transport ◽

Amino Acid Mixture ◽

Acid Mixture ◽

Acid Transport ◽

Peptide Hydrolysis ◽

Amino Acid Transport System ◽

Neutral Amino Acids

1. A double lumen perfusion technique has been used in man to study the absorption of the two neutral amino acids glycine and l-alanine from the two dipeptides, l-alanylglycine and glycyl-l-alanine and from an equivalent amino acid mixture. 2. Glycine was absorbed faster from the dipeptides than from the equivalent amino acid mixture, and the difference in absorption rates of glycine and alanine seen when the equimolar mixture of the amino acids was perfused, was abolished when either dipeptide was perfused. This suggests that dipeptides are taken up by the mucosal cell by a mechanism independent of the amino acid-transport system. 3. The presence of free amino acids in the lumen during perfusion of both dipeptides suggests that hydrolysis occurs at some stage in the uptake process. Intraluminal hydrolysis was insufficient to account for the concentration of the amino acids seen, and their presence is thought to be due to hydrolysis of the dipeptides at the brush border. 4. It is suggested that these results confirm that at least two modes of peptide absorption occur simultaneously, namely, direct peptide uptake, and peptide hydrolysis with subsequent absorption of the released amino acids by the amino acid transport system.

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Basic amino acid transport in renal papilla: microinfusion of Henle's loops and vasa recta

AJP Renal Physiology ◽

10.1152/ajprenal.1993.265.6.f830 ◽

1993 ◽

Vol 265 (6) ◽

pp. F830-F838 ◽

Cited By ~ 4

Author(s):

W. H. Dantzler ◽

S. Silbernagl

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Amino Acid Transport ◽

Basic Amino Acid ◽

Renal Papilla ◽

Tubular Structures ◽

Acid Transport ◽

Basic Amino Acids ◽

Neutral Amino Acids ◽

Vasa Recta

To determine whether basic amino acids, like acidic and neutral amino acids, could be reabsorbed distal to tips of Henle's loops and recycled between loops and vasa recta in the renal papilla, we continuously microinfused ascending Henle's loops and vasa recta with 14C-labeled L-lysine (L-Lys; 1.28 mM) or L-arginine (L-Arg; 1.17 mM) and 3H-labeled inulin. We also determined percent of recovered radiolabel as intact amino acid. Like acidic and neutral amino acids, relative to inulin, approximately 30% of L-Lys and approximately 45% of L-Arg microinfused into Henle's loops were reabsorbed. However, whereas radiolabeled L-Lys reabsorption, like reabsorption of acidic and neutral amino acids, was not readily inhibited, radiolabeled L-Arg reabsorption was reduced to approximately 25% by addition of unlabled L-Arg (50 mM) or L-homoarginine (L-Homo-Arg) (50 mM) to infusate. This observation provides greater evidence for specific, carrier-mediated reabsorption for L-Arg than for acidic or neutral amino acids. About 36% (relative to inulin) of each of these amino acids microinfused into ascending vasa recta apparently was transferred directly into ipsilateral tubular structures (probably thin descending limbs of Henle's loops). Transfer of radiolabeled L-Arg was reduced to approximately 8% by the inclusion of unlabeled L-Arg (50 mM) in infusate. Transfer of unlabeled L-Lys was unaffected by inclusion of unlabeled L-Lys (50 mM) in infusate but was reduced to approximately 20% by inclusion of unlabeled L-Arg (50 mM) or L-Homo-Arg (50 mM) in infusate. (ABSTRACT TRUNCATED AT 250 WORDS)

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Mammalian Amino Acid Transport System y + Revisited: Specificity and Cation Dependence of the Interaction with Neutral Amino Acids

The Journal of Membrane Biology ◽

10.1007/s002329900509 ◽

1999 ◽

Vol 168 (2) ◽

pp. 199-208 ◽

Cited By ~ 10

Author(s):

A.M. Rojas ◽

R. Devés

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Transport System ◽

Amino Acid Transport ◽

Acid Transport ◽

Amino Acid Transport System ◽

Neutral Amino Acids

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Amino acid transport in human and in sheep erythrocytes

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1980.0100 ◽

1980 ◽

Vol 209 (1176) ◽

pp. 355-375 ◽

Cited By ~ 35

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Amino Acid Transport ◽

Kinetic Studies ◽

Transport Systems ◽

Acid Transport ◽

Sheep Erythrocytes ◽

Neutral Amino Acids ◽

L System ◽

Dibasic Amino Acids

Amino acid transport was compared in human and in sheep erythrocytes. Kinetic studies established that human cells have three discrete amino acid transport systems, designated L, Ly + and ASC. The L system is partially stereospecific, with a preference for large neutral amino acids. L-leucine has a threefold lower apparent K m and a twofold smaller V max than D-leucine. Alanine, cysteine and possibly dibasic amino acids are transported by this route, but with a low affinity. The Ly + system is highly stereoselective, and specific for dibasic amino acids, including arginine. The ASC system is Na-dependent and selective for neutral amino acids of intermediate size. It has a particularly low apparent K m for cysteine and is stereospecific. Sheep erythrocytes lack these systems. Instead they possess an additional system (C system) responsible for the transport both of neutral and of dibasic amino acids, with cysteine as the optimal substrate. Although the substrate specificities of the human ASC and sheep C systems are similar, the sheep system does not require Na and has considerably higher apparent K m values. Dibasic amino acid transport (of lysine, but not of arginine) by the C system occurs with a low affinity.

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Amino acid transport systems of cultured soybean root cells

Canadian Journal of Botany ◽

10.1139/b75-233 ◽

1975 ◽

Vol 53 (18) ◽

pp. 2088-2091 ◽

Cited By ~ 27

Author(s):

J. King ◽

Rozina Hirji

Keyword(s):

Amino Acids ◽

Glycine Max ◽

Amino Acid ◽

Amino Acid Transport ◽

Transport Systems ◽

Acid Transport ◽

Root Cells ◽

Soybean Root ◽

Neutral Amino Acids ◽

Glycine Max L

The uptake of 1 μM14C-labelled arginine, glutamate, and alanine by cultured soybean (Glycine max L. cv. Mandarin) root cells was followed for periods up to 4 min at pH 5.5 in the presence of a 10 μM concentration of other amino compounds. From the degree of competition between 14C-labelled and unlabelled amino acids a number of uptake systems for basic, acidic, and neutral amino acids were identified, and a number of problems associated with amino acid transport in soybean cells were uncovered.

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Evidence for Distinct Amino Acid Transport Systems in Cultured Tobacco Cells

Zeitschrift für Naturforschung C ◽

10.1515/znc-1978-9-1006 ◽

1978 ◽

Vol 33 (9-10) ◽

pp. 641-645 ◽

Cited By ~ 9

Author(s):

Jochen Berlin ◽

Ulrich Mutert

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Aspartic Acid ◽

Cell Lines ◽

Amino Acid Transport ◽

Transport Systems ◽

Tobacco Cell ◽

Acid Transport ◽

Basic Amino Acids ◽

Neutral Amino Acids

Abstract It is shown by competition experiments that tobacco cell lines have distinct transport systems for ʟ-amino acids. For all tested amino acids the Lineweaver-Burk plots were diphasic indicating the presence of more than one carrier for any one amino acid. Moreover distinct transport systems for neutral, acidic and basic amino acids were kinetically characterized. Based on competition experiments neutral amino acids were absorbed by all transport systems. Aspartic acid entered the cells via its own carrier and via the basic carrier while arginine was taken up only by the basic carrier. Neutral amino acids such as ʟ-leucine or ʟ-phenylalanine were taken up faster than acidic or basic amino acids.

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