D-penicillamine and the transport of L-cystine by rat and human renal cortical brush-border membrane vesicles

1990 ◽  
Vol 258 (2) ◽  
pp. F321-F327 ◽  
Author(s):  
T. J. Furlong ◽  
S. Posen
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Binding ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Anion Diffusion ◽  
Uptake Rates ◽  
Renal Cortical Tissue ◽  
Filtration Technique

Brush-border membrane vesicles (BBMV) were prepared from rat and human renal cortical tissue by magnesium aggregation and differential centrifugation, and the uptake of L-cystine, L-cysteine, and L-cysteine-D-penicillamine were assessed by a rapid-filtration technique. L-Cystine uptake was relatively sodium independent and associated with membrane binding. Sodium-stimulated uptake was sensitive to a cation but not anion diffusion potential. Both sodium-independent and sodium-stimulated uptake rates were inhibited by the cationic L-amino acids and by some neutral L-amino acids. The uptake rates of L-cysteine and L-cysteine-D-penicillamine were more sodium dependent, and sodium-stimulated uptake rates were more sensitive to cation and anion diffusion potentials. Neither the sodium-independent nor the sodium-stimulated uptake rates of L-cysteine or L-cysteine-D-penicillamine were inhibited by the cationic L-amino acids. L-Cysteine-D-penicillamine showed relatively little membrane binding. It is concluded that L-cystine is transported into renal cortical BBMV by pathways distinct from those concerned with the transport of L-cysteine and L-cysteine-D-penicillamine, and it is postulated that these differences may account for some of the effects of D-penicillamine in cystinuria.

Potential differences influence amino acid/Na+ symport rates in larval Manduca sexta midgut brush-border membrane vesicles.

1994 ◽  
Vol 189 (1) ◽  
pp. 55-67
Author(s):  
R Parthasarathy ◽  
W R Harvey
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Manduca Sexta ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Rate Determining Step ◽  
Half Saturation Constant

The time-dependent fluorescence intensity of an intravesicular potential-sensitive dye was used to probe the real-time kinetics of potential difference (PD)-dependent amino acid/Na+ symport at pH9 into brush-border membrane vesicles obtained from larval Manduca sexta midgut. Neutral amino acids (alanine, proline) are symported at higher rates as the vesicles are hyperpolarized. The symport rates of acidic (glutamate) and basic (arginine) amino acids are almost PD-independent. The half-saturation constant of alanine is PD-independent between -108 and -78 mV, although the maximal symport velocity increases by half as the voltage is increased. Amino acid throughput is evidently enhanced as the relatively high transmembrane PDs (> 150 mV, lumen positive) measured in vivo are approached. The half-saturation concentrations of Na+ were in the range 15-40 mmol l-1 for most of the amino acids examined and increased with voltage for alanine. The Vmax observed as a function of cation or amino acid concentration increased as the vesicle was hyperpolarized in the case of leucine and alanine. The data support the hypothesis that carrier and substrates are at equilibrium inasmuch as substrate translocation seems to be the rate-determining step of symport.

scholarly journals Characterization of an ATP-driven H+ pump in human placental brush-border membrane vesicles

1992 ◽  
Vol 287 (2) ◽  
pp. 423-430 ◽  
Author(s):  
B J Simon ◽  
P Kulanthaivel ◽  
G Burckhardt ◽  
S Ramamoorthy ◽  
F H Leibach ◽  
...  
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Bafilomycin A1 ◽  
Ph Indicator ◽  
Native Form ◽  
Anion Diffusion ◽  
Partial Activity

The presence of an ATP-driven H+ pump as measured by H+ uptake upon addition of ATP was not demonstrable in human placental brush-border membrane vesicles when used in their native form, owing to their right-side-out orientation. However, the presence of the H+ pump in these membranes became evident when the membrane vesicles were transiently exposed to 1% cholate, with subsequent removal of the detergent to re-form the vesicles. Apparently, cholate pretreatment reoriented the H+ pump from an inward-facing configuration to outward-facing. Consequently, H+ uptake in response to externally added ATP was easily demonstrable in these cholate-pretreated vesicles by using the delta pH indicator Acridine Orange. In addition, bafilomycin A1-sensitive ATPase activity was measurable in cholate-pretreated vesicles, but not in native intact vesicles, indicating reorientation of the H+ pump. The reoriented H+ pump was electrogenic because H+ uptake was stimulated by an inside-negative anion-diffusion potential or when the vesicles were voltage-clamped. ATP supported H+ uptake with an apparent Km of 260 microM. ITP and GTP supported the pump activity partially, whereas CTP and UTP did not. Mg2+ and Mn2+ were the most preferred bivalent cations. Co2+ and Zn2+ showed partial activity, whereas Ca2+ and Ba2+ showed little or no activity. The pump was inhibited by nanomolar concentrations of bafilomycin A1 and micromolar concentrations of N-ethylmaleimide, p-chloromercuribenzenesulphonate, NN-dicyclohexylcarbodi-imide and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, but was relatively insensitive to oligomycin, vanadate and NaN3. The inhibition by N-ethylmaleimide was protectable by ATP. It is concluded that human placental brush-border membranes possess an ATP-driven H+ pump and that, on the basis of its characteristics, it belongs to the class of vacuolar (V-type) H+ pumps.

scholarly journals Characterization of tryptophan transport in human placental brush-border membrane vesicles

1986 ◽  
Vol 238 (1) ◽  
pp. 201-208 ◽  
Author(s):  
M E Ganapathy ◽  
F H Leibach ◽  
V B Mahesh ◽  
J C Howard ◽  
L D Devoe ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Aromatic Amino Acids ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
System 1 ◽  
Tryptophan Uptake ◽  
Tryptophan Transport

The characteristics of tryptophan uptake in isolated human placental brush-border membrane vesicles were investigated. Tryptophan uptake in these vesicles was predominantly Na+-independent. Uptake of tryptophan as measured with short incubations occurred exclusively by a carrier-mediated process, but significant binding of this amino acid to the membrane vesicles was observed with longer incubations. The carrier-mediated system obeyed Michaelis-Menten kinetics, with an apparent affinity constant of 12.7 +/- 1.0 microM and a maximal velocity of 91 +/- 5 pmol/15 s per mg of protein. The kinetic constants were similar in the presence and absence of a Na+ gradient. Competition experiments showed that tryptophan uptake was effectively inhibited by many neutral amino acids except proline, hydroxyproline and 2-(methylamino)isobutyric acid. The inhibitory amino acids included aromatic amino acids as well as other system-1-specific amino acids (system 1 refers to the classical L system, according to the most recent nomenclature of amino acid transport systems). The transport system showed very low affinity for D-isomers, was not affected by phloretin or glucose but was inhibited by p-azidophenylalanine and N-ethylmaleimide. The uptake rates were only minimally affected by change in pH over the range 4.5-8.0. Tryptophan uptake markedly responded to trans-stimulation, and the amino acids capable of causing trans-stimulation included all amino acids with system-1-specificity. The patterns of inhibition of uptake of tryptophan and leucine by various amino acids were very similar. We conclude that system t, which is specific for aromatic amino acids, is absent from human placenta and that tryptophan transport in this tissue occurs via system 1, which has very broad specificity.

Lysine transport by brush-border membrane vesicles of eel intestine: interaction with neutral amino acids

1990 ◽  
Vol 259 (6) ◽  
pp. R1181-R1188 ◽  
Author(s):  
S. Vilella ◽  
G. A. Ahearn ◽  
G. Cassano ◽  
M. Maffia ◽  
C. Storelli
Keyword(s):  
Amino Acids ◽  
Transport System ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Hill Coefficient ◽  
European Eel ◽  
Diffusional Permeability ◽  
Wide Range

L-[3H]lysine uptake was measured in brush-border membrane vesicles prepared from intestinal mucosa of the European eel Anguilla anguilla. Lysine uptake occurred via 1) a nonsaturable component with an apparent diffusional permeability (P) of 0.58 microliter.mg protein-1.min-1,2) a Na-dependent transport system [half-saturation constant (Kapp) 0.16 mM, maximal transport rate (Jmax) 3.57 nmol.mg protein-1.min-1]; 3) a Na-independent transport system (Kapp 0.17 mM, Jmax 2.77 nmol.mg protein-1.min-1). Both carrier-mediated processes were accelerated by the presence of an intravesicular negative membrane potential. Hill analysis of L-lysine influx, over a wide range of external Na concentrations, resulted in a Hill coefficient (n) of approximately 2, suggesting that two or more Na ions may be associated with amino acid transport. The inhibition of lysine uptake by other amino acids was studied. Na-dependent lysine uptake was competitively inhibited by proline [inhibitory constant (Ki) approximately 2 mM] and may occur by a system specific for cationic amino acids. Na-independent lysine uptake was competitively inhibited by alanine (Ki approximately 1 mM) and may occur by a classic L system.

Lysine uptake by rat renal brush-border membrane vesicles

1986 ◽  
Vol 251 (4) ◽  
pp. F734-F742 ◽  
Author(s):  
P. D. McNamara ◽  
C. T. Rea ◽  
S. Segal
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Choline Chloride ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Sodium Accumulation ◽  
Renal Brush Border Membrane ◽  
Dibasic Amino Acids ◽  
Renal Brush Border

Lysine uptake by isolated rat renal brush-border membrane vesicles occurs via a single saturable system plus a significant diffusion component with indication of a single energy of activation on an Arrhenius plot. Initial uptake is not sodium dependent, and intravesicular accumulation of lysine at longer time points is greatest in the absence of sodium. Accumulation levels differ in the presence or absence of NaCl or choline chloride and are specific for the cation used. Lysine uptake is membrane potential sensitive and inhibitable by cystine, dibasic amino acids, and cycloleucine. Heteroexchange diffusion of lysine with cystine and lysine with arginine occurs, but no heteroexchange occurs with cycloleucine, indicating that lysine shares a transport system with cystine and dibasic amino acids but not with cycloleucine.

Characterization of human placental activity for transport of amino acids using syncytiotrophoblast brush border membrane vesicles

Placenta ◽  
1992 ◽  
Vol 13 (4) ◽  
pp. A24
Author(s):  
Hideaki Iioka ◽  
Shinobu Akada ◽  
Takako Shimamoto ◽  
Yoshihiko Yamad ◽  
Ikuko S. Moriyama ◽  
...  
Keyword(s):  
Amino Acids ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles
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