Isolation from human erythrocytes of a new membrane protein which inhibits the formation of complement transmembrane channels

J Biochem. 1988 Oct;104(4):633-7. doi: 10.1093/oxfordjournals.jbchem.a122524.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, DEAE-Cellulose / methods
  • Complement System Proteins / physiology*
  • Erythrocyte Membrane / physiology*
  • Hemolysis / drug effects
  • Humans
  • Ion Channels / metabolism
  • Membrane Proteins / blood*
  • Membrane Proteins / isolation & purification

Substances

  • Ion Channels
  • Membrane Proteins
  • Complement System Proteins