The Phosphorus Components of Solubilized Erythrocyte Membrane Protein

1971 ◽  
Vol 49 (3) ◽  
pp. 337-347 ◽  
Author(s):  
F. B. St. C. Palmer ◽  
J. A. Verpoorte

Membrane protein preparations were obtained by n-butanol extraction of salt-free aqueous suspensions of human erythrocyte ghosts. The solubilized protein contained 4.5% carbohydrate, including glucosamine and galactosamine, 1.7% sialic acid, and 0.2% phosphorus. Gel electrophoresis indicated the presence of a large number of proteins in the solubilized fraction. Of the phosphorus present 15% could be extracted with chloroform–methanol (2/1) and was shown to consist of phosphatidylserine and some phosphatidylinositol. A further 65% of the phosphorus was extracted with chloroform–methanol–HCl (200/100/1) and this extract was shown to consist principally of diphosphoinositide and triphosphoinositide. The remaining protein-bound phosphorus, representing 0.03% of the protein, could not be separated from the protein. Following treatment with the organic solvents the protein was resolubilized. The carbohydrate and sialic acid concentrations and the gel electrophoretic pattern were not altered. Following incubation of erythrocytes with inorganic 32P, the polyphosphoinositides were rapidly labelled. The phosphoprotein was also rapidly labelled but to a lesser extent. The phosphatidylinositol and phosphatidylserine were very poorly labelled.

1974 ◽  
Vol 63 (3) ◽  
pp. 1018-1030 ◽  
Author(s):  
Arnljot Elgsaeter ◽  
Daniel Branton

We have used freeze-etching and SDS-polyacrylamide gel electrophoresis to study the conditions under which the intramembrane particles of the human erythrocyte ghost may be aggregated. The fibrous membrane protein, spectrin, can be almost entirely removed from erythrocyte ghosts with little or no change in the distribution of the particles. However, after spectrin depletion, particle aggregation in the plane of the membrane may be induced by conditions which cause little aggregation in freshly prepared ghosts. This suggests that the spectrin molecules form a molecular meshwork which limits the translational mobility of the erythrocyte membrane particles.


1974 ◽  
Vol 137 (3) ◽  
pp. 531-534 ◽  
Author(s):  
D. H. Boxer ◽  
R. E. Jenkins ◽  
M. J. A. Tanner

The enzyme lactoperoxidase was used to catalyse the radioiodination of membrane proteins in intact human erythrocytes and in erythrocyte ‘ghosts’. Two major proteins of the erythrocyte membrane were isolated after iodination of these two preparations, and the peptide ‘maps’ of each protein so labelled were compared. Peptides from both proteins are labelled in the intact cell. In addition, further mobile peptides derived from one of the proteins are labelled only in the ‘ghost’ preparation. Various sealed ‘ghost’ preparations were also iodinated, lactoperoxidase being present only at either the cytoplasmic or extra-cellular surface of the membrane. The peptide ‘maps’ of protein E (the major membrane protein) labelled in each case were compared. Two discrete sets of labelled peptides were consistently found. One group is obtained when lactoperoxidase is present at the extra-cellular surface and the other group is found when the enzyme is accessible only to the cytoplasmic surface of the membrane. The results support the assumption that the organization of protein E in the membrane of the intact erythrocyte is unaltered on making erythrocyte ‘ghosts’. They also confirm previous suggestions that both the sialoglycoprotein and protein E extend through the human erythrocyte membrane.


1974 ◽  
Vol 140 (3) ◽  
pp. 557-560 ◽  
Author(s):  
Cesare Balduini ◽  
Carlo Luigi Balduini ◽  
Edoardo Ascari

Glycopeptides were extracted by papain digestion from old and young human erythrocyte membranes and fractionated on DEAE-Sephadex A-25. Chemical characterization of the unfractionated samples and of the main peak eluted from the column indicates that glycoproteins of the erythrocyte membrane undergo significant decreases in sialic acid and galactosamine content with aging.


Blood ◽  
1984 ◽  
Vol 64 (3) ◽  
pp. 599-606 ◽  
Author(s):  
MJ Telen ◽  
TJ Palker ◽  
BF Haynes

Abstract We have previously shown that a murine monoclonal antibody (A3D8) identifies a human erythrocyte protein antigen whose expression is regulated by the Lutheran inhibitor [In(Lu)] gene. In the present study, we demonstrated by immunoprecipitation and Western blot techniques that the antigen defined by A3D8 was on an 80-kD erythrocyte membrane protein. A second 170-kD protein was coprecipitated with the 80-kD protein but failed to show antigen activity by Western blot analysis. The 170-kD protein, when analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis in two dimensions, was composed of 50- and 30-kD disulfide-linked subunits. In(Lu) Lu[a-b-) erythrocytes differed from Lu(a+b+) or Lu(a-b+) erythrocytes in that In(Lu) deoxycholate erythrocyte membrane extracts contained trace amounts of immunoprecipitable 80-kD protein compared with detergent-solubilized erythrocyte membrane extracts prepared from Lu(a+b+) or Lu(a-b+) subjects.


1979 ◽  
Vol 179 (2) ◽  
pp. 299-303 ◽  
Author(s):  
R S Pratt ◽  
G M Cook

1. The enzymic removal of sialic acid residues from the glycoproteins of the human erythrocyte decreases the solubilization of membrane glycoprotein by Triton X-100. 2. The solubilization of asialoglycoprotein by Triton X-100 may be restored by the addition of borate. 3. Use of this non-ionic detergent in the presence of borate, as a general procedure for the mild solubilization of membrane glycoproteins deficient in sialic acid residues, is discussed.


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