scholarly journals Corrigendum to: ‘Leukotriene C4 (LTC4) does not share a cellular efflux mechanism with cGMP: characterisation of cGMP transport by uptake to inside-out vesicles from human erythrocytes’ [Biochim. Biophys. Acta 1463 (2000) 121–130]

2000 ◽  
Vol 1467 (2) ◽  
pp. 457 ◽  
Author(s):  
Elisabeth Sundkvist ◽  
Ragnhild Jaeger ◽  
Georg Sager
Keyword(s):  
Human Erythrocytes ◽  
Leukotriene C4 ◽  
Efflux Mechanism ◽  
Inside Out

Low- and high-Km transport of dinitrophenyl glutathione in inside out vesicles from human erythrocytes

1992 ◽  
Vol 1103 (1) ◽  
pp. 115-119 ◽  
Author(s):  
Theodorus P.M. Akerboom ◽  
Grzegorz Bartosz ◽  
Helmut Sies
Keyword(s):  
Human Erythrocytes ◽  
Inside Out

Membrane orientation of sheep spectrin

1980 ◽  
Vol 58 (10) ◽  
pp. 1120-1130
Author(s):  
P. Prokopchuk ◽  
A. U. Sargent
Keyword(s):  
Sheep Erythrocyte ◽  
Human Erythrocytes ◽  
Erythrocyte Membranes ◽  
Variable Degree ◽  
Vertebrate Species ◽  
Membrane Orientation ◽  
Cytoplasmic Surface ◽  
Immunofluorescence Studies ◽  
Surface Labelling ◽  
Inside Out

Based primarily on studies of human erythrocytes, current theories of the structure and organization of erythrocyte membranes localize spectrin to the membrane cytoplasmic surface. Affinity purified anti-sheep spectrin antibodies were used in indirect immunofluorescence studies of intact erythrocytes from various vertebrate species and inside-out and right-side-out impermeable sheep erythrocyte vesicles. This investigation detected i0mmunologically reactive external and potentially transmembranal determinant(s) of the sheep erythrocyte spectrin "assembly." Parallel studies using anti-sheep and anti-human spectrin antibodies, as well as 125I surface-labelling studies of intact sheep and human erythrocytes, indicated that this particular membrane orientation of spectrin was evident in sheep but not in human erythrocytes. Antisera containing antibodies to the external portion of this spectrin "assembly" demonstrated external fluorescence to a variable degree on some, but not all, vertebrate erythrocytes surveyed, confirming that the sheep erythrocyte was not the only exception. It is suggested that there may be subtle species variability in the intermolecular associations of the spectrin "assembly" with(in) the erythrocyte membrane not requiring alterations of the spectrin molecule itself.

Simple and rapid purification of inside-out vesicles from human erythrocytes

1980 ◽  
Vol 602 (1) ◽  
pp. 127-130 ◽  
Author(s):  
Takahito Kondo ◽  
George L. Dale ◽  
Ernest Beutler
Keyword(s):  
Human Erythrocytes ◽  
Rapid Purification ◽  
Inside Out

scholarly journals Human erythrocytes transport dehydroascorbic acid and sugars using the same transporter complex

2014 ◽  
Vol 306 (10) ◽  
pp. C910-C917 ◽  
Author(s):  
Jay M. Sage ◽  
Anthony Carruthers
Keyword(s):  
Steady State ◽  
Vitamin C ◽  
Blood Cells ◽  
Dehydroascorbic Acid ◽  
Membrane Vesicles ◽  
Human Erythrocytes ◽  
Cytoplasmic Surface ◽  
Glucose Transport Protein ◽  
Inside Out ◽  
Primary Substrate

GLUT1, the primary glucose transport protein in human erythrocytes [red blood cells (RBCs)], also transports oxidized vitamin C [dehydroascorbic acid (DHA)]. A recent study suggests that RBC GLUT1 transports DHA as its primary substrate and that only a subpopulation of GLUT1 transports sugars. This conclusion is based on measurements of cellular glucose and DHA equilibrium spaces, rather than steady-state transport rates. We have characterized RBC transport of DHA and 3- O-methylglucose (3-OMG), a transported, nonmetabolizable sugar. Steady-state 3-OMG and DHA uptake in the absence of intracellular substrate are characterized by similar Vmax (0.16 ± 0.01 and 0.13 ± 0.02 mmol·l−1·min−1, respectively) and apparent Km (1.4 ± 0.2 and 1.6 ± 0.7 mM, respectively). 3-OMG and DHA compete for uptake, with Ki(app) of 0.7 ± 0.4 and 1.1 ± 0.1 mM, respectively. Uptake measurements using RBC inside-out-membrane vesicles demonstrate that 3-OMG and DHA compete at the cytoplasmic surface of the membrane, with Ki(app) of 0.7 ± 0.1 and 0.6 ± 0.1 mM, respectively. Intracellular 3-OMG stimulates unidirectional uptake of 3-OMG and DHA. These findings indicate that DHA and 3-OMG bind at mutually exclusive sites at exo- and endofacial surfaces of GLUT1 and are transported via the same GLUT1 complex.

scholarly journals Calmodulin regulation of Ca2+ transport in human erythrocytes

1981 ◽  
Vol 200 (2) ◽  
pp. 185-191 ◽  
Author(s):  
F L Larsen ◽  
S Katz ◽  
B D Roufogalis
Keyword(s):  
Atpase Activity ◽  
Human Erythrocytes ◽  
Stoichiometric Ratio ◽  
Transport Activity ◽  
Electrochemical Gradient ◽  
Edta Treatment ◽  
Calmodulin Binding ◽  
High Affinity ◽  
Transport Component ◽  
Inside Out

Inside-out vesicles of human erythrocytes took up Ca2+ against an electrochemical gradient. This Ca2+ uptake was dependent on ATP and was stimulated by calmodulin. Treatment of vesicles with 1 mM-EDTA exposed an apparent low-CA2+-affinity Ca2+-transport component with Kd of about 100 microM-Ca2+ or more. This was converted into a single high-Ca2+-affinity transport activity of Kd about 2.5 microM-Ca2+ in the presence of 2 micrograms of calmodulin/ml, showing that the decrease in transport activity after EDTA treatment was reversible. Vesicles not extracted with EDTA showed mainly apparent high-Ca2+-affinity kinetics even in the absence of added calmodulin. Trifluoperazine (30 microM) and calmodulin-binding protein (20 micrograms/ml) inhibited about 50% of the high-affinity Ca2+ uptake and (Ca2+ + Mg2+)-ATPase (Ca2+-activated, Mg2+-dependent ATPase) activity of these vesicles, indicating that the vesicles isolated by the procedure used retained some calmodulin from the erythrocytes. Comparison of Ca2+ transport and (Ca2+ + Mg2+)-ATPase activities in inside-out vesicles yielded a variable Ca2+/P1 stoichiometric ratio. At low free Ca2+ concentrations (below 20 micro-Ca2+), a Ca2+/P1 ration of about 2 was found, whereas at higher Ca2+ concentrations the stoichiometry was approx. 1. The stoichiometry was not significantly altered by calmodulin.

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