The stereospecific d-glucose transport activity of cholate extracts from human erythrocyte membranes

1981 ◽  
Vol 644 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Per Lundahl ◽  
Fernando Acevedo ◽  
Gunnar Fröman ◽  
Suree Phutrakul
Keyword(s):  
Glucose Transport ◽  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Transport Activity ◽  
Human Erythrocyte Membranes

Evidence against the Involvement of Mutarotase in the D-Glucose Uptake Activity of Isolated Human Erythrocyte Membranes

1972 ◽  
Vol 50 (9) ◽  
pp. 1028-1030 ◽  
Author(s):  
Arthur Kahlenberg ◽  
Gary Miller
Keyword(s):  
Glucose Uptake ◽  
Membrane Transport ◽  
Glucose Transport ◽  
Human Erythrocyte ◽  
Transport Process ◽  
Human Erythrocytes ◽  
Erythrocyte Membranes ◽  
Human Erythrocyte Membranes ◽  
Uptake Activity ◽  
Glucose Carrier

Mutarotase, the enzyme catalyzing the interconversion of the anomeric forms of D-glucose, has recently been suggested to be the membrane glucose carrier in human erythrocytes. However, hemoglobin-free human erythrocyte membranes possessing D-glucose uptake activity were found to be free of mutarotase activity. Mutarotase activity was detected in the membrane-free hemolysates of the cells. It is therefore concluded that the D-glucose uptake activity of isolated erythrocyte membranes is not due to the binding of the sugar to mutarotase, and that this enzyme is not involved in glucose transport in a manner compatible with most presently held concepts of the membrane transport process.

scholarly journals Some transport properties of resealed washed human erythrocyte membranes

1978 ◽  
Vol 172 (3) ◽  
pp. 605-611 ◽  
Author(s):  
W J Mawby ◽  
J B C Findlay
Keyword(s):  
Glucose Transport ◽  
Human Erythrocyte ◽  
Phosphate Transport ◽  
Isolation Procedure ◽  
Transport Systems ◽  
Erythrocyte Membranes ◽  
Human Erythrocyte Membranes ◽  
Membrane Isolation ◽  
Phosphate Exchange ◽  
Protein Mediator

A comparison was made between the phosphate- and glucose-transport systems of intact erythrocytes and resealed washed membranes. Glucose transport exhibits identical properties in both cases, but the phosphate-transport system does not appear to have survived the membrane isolation procedure unaltered. Evidence is presented to support the suggestion that some form of structural perturbation has occurred to the protein mediator of phosphate exchange.

scholarly journals Interaction of platelet plasma membranes with thrombin-activated platelets

Blood ◽  
1981 ◽  
Vol 57 (2) ◽  
pp. 305-312 ◽  
Author(s):  
HR Prasanna ◽  
HH Edwards ◽  
DR Phillips
Keyword(s):  
Human Erythrocyte ◽  
Plasma Membranes ◽  
Membrane Binding ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Erythrocyte Membranes ◽  
Functional Sites ◽  
Activated Platelets ◽  
Platelet Membranes ◽  
Human Erythrocyte Membranes

Abstract This study described the binding of platelet plasma membranes to either control or thrombin-activated platelets. Glycoproteins in plasma membranes isolated from human platelets were labeled by oxidation with periodate followed by reduction with [3H]NaBH4. Labeled membranes were incubated with either control or thrombin-activated platelets. The amount of membranes bound was measured by separating platelets with bound membranes from solution by rapid centrifugation through 27% sucrose and determining the amount of radioactivity associated with platelets. Five- to sevenfold more membranes bound to thrombin- activated platelets than to control platelets. This enhanced binding of labeled membranes was completely inhibited by an excess of unlabeled platelet membranes. Human erythrocyte membranes had little affinity for either washed or thrombin-activated platelets and therefore did not compete for platelet-membrane binding. Binding of platelet membranes to thrombin-treated platelets was inhibited by prior incubation of the platelets with PGI2 suggesting that the enhanced binding of membranes was to activated platelets. This study demonstrates that the purified platelet membranes have functional sites that can mediate membrane binding to platelets and that quantitation of membrane binding appears to reflect the increased aggregation capability of activated platelets.

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