scholarly journals Reconstitution of the Ca2+-transport system of human erythrocytes

1980 ◽  
Vol 188 (1) ◽  
pp. 47-54 ◽  
Author(s):  
K Gietzen ◽  
S Seiler ◽  
S Fleischer ◽  
H U Wolf
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Transport System ◽  
Human Erythrocyte ◽  
Room Temperature ◽  
Proteinase Inhibitors ◽  
Membrane Vesicles ◽  
Tween 20 ◽  
Erythrocyte Ghosts ◽  
Lipid Ratio

The (Ca2+ + Mg2+)-dependent ATPase of human erythrocyte ‘ghosts’ was solubilized and reconstituted to form membranous vesicles capable of energized Ca2+ accumulation. The erythrocyte ‘ghosts’ for this purpose were prepared by using isoosmotic freeze-haemolysis in the presence of Tween 20 and proteinase inhibitors to stabilize the preparation. The reconstitution procedure is similar to that developed by Meissner & Fleischer [(1974) J. Biol. Chem. 249, 302-309] for skeletal-muscle sarcoplasmic-reticulum in that: (1) deoxycholate is used for the solubilization of the membrane; (2) controlled dialysis at near room temperature, rather than 0 degree C, is required in order to obtain a functional preparation capable of Ca2+ accumulation; and (3) membrane vesicles can be reassembled with protein/lipid ratio (approx. 60% protein and 40% lipid) similar to that of the original membrane.

Lead and calcium transport in human erythrocyte

1999 ◽  
Vol 18 (5) ◽  
pp. 327-332 ◽  
Author(s):  
J V Calderón-Salinas ◽  
M A Quintanar-Escorcia ◽  
M T González-Martínez ◽  
C E Hernández-Luna
Keyword(s):  
Transport System ◽  
Human Erythrocyte ◽  
Calcium Transport ◽  
Human Erythrocytes ◽  
The Other ◽  
Erythrocyte Ghosts ◽  
Passive Transport ◽  
Ca Uptake

In this paper we report the lead (Pb) and calcium (Ca) uptake by erythrocyte ghosts. In both cases the transport was carried out by a passive transport system with two kinetic components (Michaelis-Menten and Hill). Pb and Ca were capable of inhibiting the transport of the other metal in a non-competitive way. Under hyperpolarization, the uptakes of Ca and Pb were enhanced and the Michaelis-Menten component prevailed. Both Ca and Pb uptakes were inhibited by N-ethyl-maleimide to the same extent. These results indicate that Pb and Ca share the same permeability pathway in human erythrocytes and that this transport system is electrogenic.

scholarly journals Active transport of GSSG from reconstituted erythrocyte ghosts

Blood ◽  
1975 ◽  
Vol 46 (1) ◽  
pp. 111-117 ◽  
Author(s):  
J Prchal ◽  
SK Srivastava ◽  
E Beutler
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Concentration Gradient ◽  
Human Erythrocyte ◽  
Red Cells ◽  
Intracellular Concentration ◽  
Maximal Velocity ◽  
Erythrocyte Ghosts ◽  
The Relationship

Abstract Human erythrocyte ghosts were loaded with 35S-labeled GSSG and with a sucrose marker, and the transport of GSSG to the suspending medium was studied. GSSG transport from ghosts occurred only when ATP was also present in the ghosts, proceeded against a concentration gradient, and was inhibited by fluoride. The rate of transport was dependent upon the intracellular concentration of GSSG. The relationship between GSSG concentration and rate of transport was sigmoidal. Half-maximal transport was observed at a GSSG concentration of approximately 9.6mM. The maximal velocity was estimated to be in the range of 0.27 umole GSSG per ml of ghosts per hr. These data suggest that the rate of GSSG transport a physiologic concentrations of GSSG is not sufficiently rapid to account for the turnover of glutathione by red cells. It seems more likely that the GSSG transport system serves an emergency function of erythrocytes.

Two-dimensional structure of phospholipase induced crystals of Ca2+-ATPase from sarcoplasmic reticulum

1986 ◽  
Vol 6 (12) ◽  
pp. 1065-1070 ◽  
Author(s):  
M. Misra ◽  
S. K. Malhotra
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Phospholipase A2 ◽  
Membrane Vesicles ◽  
Rabbit Skeletal Muscle ◽  
Dimensional Structure ◽  
Two Dimensional

A two-dimensional projection map was computed of the Ca2+-ATPase molecules in sarcoplasmic reticulum, isolated from rabbit skeletal muscle. Crystalline arrays of Ca2+-ATPase molecules were formed by incubating the membrane vesicles with phospholipase A2 and dialysing against Tris/HCl buffer. Ca2+-ATPase molecules appear as quasi-triangular blobs in the projection map and seem to form dimers. The projection map seems to indicate an enzyme conformation somewhat similar to vanadate-induced crystals but different from lanthanide-induced crystals of Ca2*-ATPase.

scholarly journals Active transport of GSSG from reconstituted erythrocyte ghosts

Blood ◽  
1975 ◽  
Vol 46 (1) ◽  
pp. 111-117
Author(s):  
J Prchal ◽  
SK Srivastava ◽  
E Beutler
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Concentration Gradient ◽  
Human Erythrocyte ◽  
Red Cells ◽  
Intracellular Concentration ◽  
Maximal Velocity ◽  
Erythrocyte Ghosts ◽  
The Relationship

Human erythrocyte ghosts were loaded with 35S-labeled GSSG and with a sucrose marker, and the transport of GSSG to the suspending medium was studied. GSSG transport from ghosts occurred only when ATP was also present in the ghosts, proceeded against a concentration gradient, and was inhibited by fluoride. The rate of transport was dependent upon the intracellular concentration of GSSG. The relationship between GSSG concentration and rate of transport was sigmoidal. Half-maximal transport was observed at a GSSG concentration of approximately 9.6mM. The maximal velocity was estimated to be in the range of 0.27 umole GSSG per ml of ghosts per hr. These data suggest that the rate of GSSG transport a physiologic concentrations of GSSG is not sufficiently rapid to account for the turnover of glutathione by red cells. It seems more likely that the GSSG transport system serves an emergency function of erythrocytes.

scholarly journals Is the Calcium Pump Involved in Calcium Release?

1986 ◽  
Vol 41 (5-6) ◽  
pp. 647-651 ◽  
Author(s):  
Martina Ungeheuer ◽  
Andrea Migala ◽  
Wilhelm Hasselbach
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Transport System ◽  
Calcium Transport ◽  
Calcium Release ◽  
Membrane Vesicles ◽  
Calcium Pump ◽  
Complete Inactivation ◽  
Calcium Induced Calcium Release

The blockage of all thiol residues accessible to the mercurial mersalyl in the sarcoplasmic reticulum membranes resulting in complete inactivation of the membranes’ calcium transport system does interfere neither with caffeine- nor calcium-induced calcium release from actively loaded membrane vesicles.

Control of intracellular Ca2+ activity in rat myometrium

1977 ◽  
Vol 232 (1) ◽  
pp. 50-58 ◽  
Author(s):  
R. A. Janis ◽  
D. J. Crankshaw ◽  
E. E. Daniel
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Control System ◽  
Sarcoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Membrane Vesicles ◽  
High Energy ◽  
The Other ◽  
Relative Potential

Four fractions enriched, respectively, in plasma membrane (PM), smooth endoplasmic reticulum (SER), rough endoplasmic reticulum (RER), and mitochondria were isolated from estrogen-dominated rat myometrium. Ca2+ uptake by these fractions was studied in order to estimate the relative potential of the corresponding organelles for controlling intracellular Ca2+ activity. Ca2+ uptake properties of the PM, SER, and RER fractions were similar except that potentiation by oxalate was in the order RER greater than or equal SER greater than PM. However, studies with the ionophores X-537A and A23187 suggested that Ca2+ was transported into the lumen of membrane vesicles of all these fractions. Unlike that of skeletal muscle sarcoplasmic reticulum, Ca2+ uptake by the myometrial fractions was not supported by high-energy compounds other than ATP. Mitochondria took up much less Ca2+ at low, and much more Ca2+ at high, free Ca2+ concentrations than did the other fractions. The amount of Ca2+ taken up in 30 s from a 1 muM free Ca2+ solution in the presence of ATP was similar for all fractions. These results suggested that mitochondria may act as an important Ca2+ control system in rat myometrium when the intracellular Ca2+ concentration is near 1 muM or higher, whereas the PM, SER, and RER may be of major importance at Ca2+ levels of 0.3 muM or lower.

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