Role of substrate binding forces in exchange-only transport systems: II. Implications for the mechanism of the anion exchanger of red cells

1989 ◽  
Vol 109 (2) ◽  
pp. 159-171 ◽  
Author(s):  
R. M. Krupka
Keyword(s):  
Anion Exchanger ◽  
Substrate Binding ◽  
Red Cells ◽  
Transport Systems ◽  
Binding Forces

Oxygen-sensitive membrane transporters in vertebrate red cells

2000 ◽  
Vol 203 (9) ◽  
pp. 1395-1407 ◽  
Author(s):  
J.S. Gibson ◽  
A.R. Cossins ◽  
J.C. Ellory
Keyword(s):  
Membrane Transporters ◽  
Red Cells ◽  
Transport Systems ◽  
Red Cell ◽  
Organic Systems ◽  
Wide Range ◽  
Oxygen Sensitive ◽  
Radical Generation ◽  
Membrane Transport Systems

Oxygen is essential for all higher forms of animal life. It is required for oxidative phosphorylation, which forms the bulk of the energy supply of most animals. In many vertebrates, transport of O(2) from respiratory to other tissues, and of CO(2) in the opposite direction, involves red cells. These are highly specialised, adapted for their respiratory function. Intracellular haemoglobin, carbonic anhydrase and the membrane anion exchanger (AE1) increase the effective O(2)- and CO(2)-carrying capacity of red cells by approximately 100-fold. O(2) also has a pathological role. It is a very reactive species chemically, and oxidation, free radical generation and peroxide formation can be major hazards. Cells that come into contact with potentially damaging levels of O(2) have a variety of systems to protect them against oxidative damage. Those in red cells include catalase, superoxide dismutase and glutathione. In this review, we focus on a third role of O(2), as a regulator of membrane transport systems, a role with important consequences for the homeostasis of the red cell and also the organism as a whole. We show that regulation of red cell transporters by O(2) is widespread throughout the vertebrate kingdom. The effect of O(2) is selective but involves a wide range of transporters, including inorganic and organic systems, and both electroneutral and conductive pathways. Finally, we discuss what is known about the mechanism of the O(2) effect and comment on its physiological and pathological roles.

scholarly journals Role of Na+ in the Transport of Amino Acids in Rabbit Red Cells

1967 ◽  
Vol 242 (7) ◽  
pp. 1450-1457
Author(s):  
Kenneth P. Wheeler ◽  
Halvor N. Christensen
Keyword(s):  
Amino Acids ◽  
Red Cells

The Role of Politics in the Historical Transport Networks of the Iberian Peninsula and the Pyrenees from Roman Times to the Nineteenth Century

2021 ◽  
Vol 45 (2) ◽  
pp. 233-260
Author(s):  
Pau de Soto ◽  
Cèsar Carreras
Keyword(s):  
Iberian Peninsula ◽  
Social Factors ◽  
Transport Network ◽  
Political Organization ◽  
Transport Systems ◽  
The Political ◽  
Political Systems ◽  
Transport Networks ◽  
Political Economic

AbstractTransport routes are basic elements that are inextricably linked to diverse political, economic, and social factors. Transport networks may be the cause or result of complex historical conjunctions that reflect to some extent a structural conception of the political systems that govern each territory. It is for this reason that analyzing the evolution of the transport routes layout in a wide territory allows us to recognize the role of the political organization and its economic influence in territorial design. In this article, the evolution of the transport network in the Iberian Peninsula has been studied in a broad chronological framework to observe how the different political systems of each period understood and modified the transport systems. Subsequently, a second analysis of the evolution of transport networks in the northeast of the Iberian Peninsula is included in this article. This more detailed and geographically restricted study allows us to visualize in a different way the evolution and impact of changes in transport networks. This article focuses on the calculation of the connectivity to analyze the intermodal transport systems. The use of network science analyses to study historical roads has resulted in a great tool to visualize and understand the connectivity of the territories of each studied period and compare the evolution, changes, and continuities of the transport network.

The role of Glu196 in the environment around the substrate binding site of leucine aminopeptidase fromStreptomyces griseus

FEBS Letters ◽  
2006 ◽  
Vol 580 (3) ◽  
pp. 912-917 ◽  
Author(s):  
Jiro Arima ◽  
Yoshiko Uesugi ◽  
Misugi Uraji ◽  
Masaki Iwabuchi ◽  
Tadashi Hatanaka
Keyword(s):  
Binding Site ◽  
Leucine Aminopeptidase ◽  
Substrate Binding ◽  
Substrate Binding Site

Myocardial CO2 buffering: role of transmembrane transport of H+ or HCO3-ions

1976 ◽  
Vol 230 (4) ◽  
pp. 1037-1041 ◽  
Author(s):  
DR Strome ◽  
RL Clancy ◽  
NC Gonzalez
Keyword(s):  
Small Volume ◽  
Coronary Circulation ◽  
Myocardial Cell ◽  
Ringer Solution ◽  
Red Cells ◽  
Transmembrane Transport ◽  
High Degree

Isolated rabbit hearts were perfused with rabbit red cells suspended in Ringer solution. A small volume of perfusate was recirculated for 10 min at Pco2 of 33.4 +/- 0.9 or 150.8 +/- 7.5 mmHg. Hypercapnia resulted in an increase in perfusate HCO3- concentration that was smaller than that observed when isolated perfusate was equilibrated in vitro with the same CO2 tensions (delta HCO-3e = 1.6 mM, P less than 0.01). This difference is consistent with a net movement of HCO3- into or H+ out of the mycardial cell, and cannot be accounted for by dilution of HCO3- in the myocardial interstitium. Recirculation of perfusate through the coronary circulation at normal Pco2 for two consecutive 10-min periods was not followed by changes in perfusate HCO3- concentration. A high degree of correlation (r = 0.81) was observed between intracellular HCO-3e concentration and the corresponding delta HCO-3e in individual experiments. The results suggest that transmembrane exchange of H+ or HCO3- is a buffer mechanism for CO2 in the myocardial cell.

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