Isolation from human erythrocytes of a new membrane protein which inhibits the formation of complement transmembrane channels.
A protein which inhibited complement channel formation was isolated from extracts of papain-digested human erythrocyte membranes using DEAE-Sephacel, Bio-Gel A0.5m column chromatographies, and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by transfer to nitrocellulose paper and elution with 2% NP-40 solution. The purified protein showed a molecular weight of 18 kDa, and efficiently inhibited hemolysis of EC5-7 cells with C8 and C9, but did not show any decay-accelerating activity to C5 convertase. Immunochemical analysis of native membranes after sodium dodecyl sulfate-polyacrylamide gel electrophoresis using the antibody against this protein gave a single band having the same mobility as this protein; papain did not eliminate a significant portion of this protein.
Sugita
Y
Y
Department of Physiological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo.
Nakano
Y
Y
Tomita
M
M
D002848:Chromatography, DEAE-Cellulose / Q000379:methods; D003165:Complement System Proteins / Q000502:physiology*; D004910:Erythrocyte Membrane / Q000502:physiology*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D008565:Membrane Proteins / Q000097:blood* / Q000302:isolation & purification
D007473:Ion Channels; D008565:Membrane Proteins; D003165:Complement System Proteins