Association of glycoproteins with the membranes. II. Isolation and partial characterization of lipophilic fragment from human erythrocyte membrane glycoprotein

Biochemistry ◽  
1974 ◽  
Vol 13 (18) ◽  
pp. 3639-3642 ◽  
Author(s):  
Javaid I. Javaid ◽  
Richard J. Winzler
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Partial Characterization ◽  
Membrane Glycoprotein ◽  
Human Erythrocyte Membrane

scholarly journals Solubilization of human erythrocyte membrane glycoproteins by triton X-100

1979 ◽  
Vol 179 (2) ◽  
pp. 299-303 ◽  
Author(s):  
R S Pratt ◽  
G M Cook
Keyword(s):  
Sialic Acid ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
General Procedure ◽  
Membrane Glycoprotein ◽  
Membrane Glycoproteins ◽  
Human Erythrocyte Membrane ◽  
Ionic Detergent ◽  
Triton X ◽  
Mild Solubilization

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.

scholarly journals Identification of the membrane glycoprotein that is the C3b receptor of the human erythrocyte, polymorphonuclear leukocyte, B lymphocyte, and monocyte

1980 ◽  
Vol 152 (1) ◽  
pp. 20-30 ◽  
Author(s):  
DT Fearon
Keyword(s):  
B Lymphocytes ◽  
Erythrocyte Membrane ◽  
Polymorphonuclear Leukocyte ◽  
Human Erythrocyte ◽  
B Lymphocyte ◽  
Sodium Dodecyl ◽  
Scatchard Analysis ◽  
Membrane Glycoprotein ◽  
Human Erythrocyte Membrane ◽  
C3b Receptor

A human erythrocyte membrane glycoprotein of 205,000 mol wt (gp205) has been identified as the C3b receptor of the erythrocyte, polymorphonuclear leukocyte (PMN), B lymphocyte, and monocyte. Initially, gp205 was sought and characterized as a constituent of the human erythrocyte membrane that can impair activation of the alternative complement pathway by inducing loss of function of the properdin-stabilized amplification C3 convertase (C3b,Bb,P) through displacement of Bb from C3b and by promoting cleavage-inactivation of C3b by C3b inactivator. These inhibitory activities of gp205 suggested that this membrane glyeoprotein had an affinity for C3b and prompted an analysis of its possible identity as the C3b receptor of human peripheral blood cells. The F(ab')2 fragment of rabbit IgG anti-gp205 inhibited the formation of rosettes with sheep EC3b of human erythroeytes, B lymphocytes, monocytes and PMN in a dose-response manner; the 50 percent inhibitory doses were 0.13/μg/ml, 0.90 μg/ml, 1.25 μg/ml, and 1.20 μg/ml of F(ab')2, respectively. Anti-gp205 did not impair the formation of rosettes by monocytes and B lymphocytes with sheep EC3bi or with EC3d. Scatchard analysis of the number of specific (125)I-F(ab')(2) anti-gp205 binding sites/cell revealed 950 sites/erythrocyte, 21,000 sites/cell of B lymphocyte preparation, 57,000 sites/PMN, and 48,000 sites/monocyte, indicating that the higher concentrations of antibody that had been required for inhibition of rosette formation by the nucleated cells reflected larger numbers of receptors on these cells. Direct evidence for the identity of gp205 as the C3b receptor of the four cell types was obtained when detergent-solubilized membrane proteins of the surface-radioiodinated cells were reacted with anti- gp205 and the immunoprecipitate was analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. In each instance, the antigenic material reacting with anti-gp205 represented a single protein with an apparent 205,000 mol wt. Thus, gp205 is the C3b receptor of human erythrocytes, PMN, B lymphocytes, and monocytes.

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