Amino-terminal amino acid sequence and chemical and functional properties of a membrane attack complex-inhibitory factor from human erythrocyte membranes.
The protein corresponding to P-18 (Sugita et al. (1988) J. Biochem, 104, 633-637) was isolated from native human erythrocyte, and newly designated membrane attack complex-inhibitory factor (MACIF). The amino-terminal sequence of this protein was determined to be Leu-Gln-Cys-Tyr-Asn-Cys-Pro-Asn-Pro-Thr. Endoglycosidase F digestion of MACIF decreased its molecular weight by about 6K on SDS-PAGE. On the other hand, endoglycosidase H, neuraminidase, or endo-alpha-N-acetylgalactosaminidase treatment had no effect on the molecular weight, indicating that MACIF has complex-type N-linked oligosaccharide chains, but no O-linked chain. MACIF was highly resistant against trypsin digestion and heat treatment. The inhibitory activity of MACIF on the hemolysis of EC5-8 cells was comparable to that on EC5-7 cells, indicating that MACIF inhibited the binding of C9 to the intermediate cells, or the subsequent C9 polymerization.
Sugita
Y
Y
Department of Physiological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo.
Mazda
T
T
Tomita
M
M
D000595:Amino Acid Sequence; D000606:Amino Sugars / Q000032:analysis; D000818:Animals; D001798:Blood Proteins / Q000235:genetics*; D018957:CD59 Antigens; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D015938:Complement Membrane Attack Complex / Q000037:antagonists & inhibitors*; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006168:Guinea Pigs; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D008970:Molecular Weight
D000606:Amino Sugars; D001798:Blood Proteins; D018957:CD59 Antigens; D015938:Complement Membrane Attack Complex