The effect of residue 1106 on the thioester-mediated covalent binding reaction of human complement protein C4 and the monomeric rat alpha-macroglobulin alpha 1 I3.


Journal Article

The histidine at position 1106 of the C4B isotype of human complement is involved in catalyzing the covalent binding of the thioester to glycerol and water. By replacing the histidine with other residues, it was found that tyrosine is also capable of mediating the reaction. We propose that they act as nucleophiles by first attacking the thioester, upon activation, to form acyl intermediates, which subsequently react with the hydroxyl groups of glycerol or water. The monomeric alpha-macroglobulin, alpha 1I3 of the rat, was also studied. Unlike alpha 2-macroglobulin, which is a tetramer, alpha 1I3 has binding properties similar to those of C4A.

Full Text

Cited Authors

  • Ren, XD; Dodds, AW; Enghild, JJ; Chu, CT; Law, SK

Published Date

  • July 1995

Published In

Volume / Issue

  • 368 / 1

Start / End Page

  • 87 - 91

PubMed ID

  • 7542207

Pubmed Central ID

  • 7542207

Electronic International Standard Serial Number (EISSN)

  • 1873-3468

International Standard Serial Number (ISSN)

  • 0014-5793

Digital Object Identifier (DOI)

  • 10.1016/0014-5793(95)00606-a


  • eng