title: The association of the subunits of component C3 of hagfish complement is unstable and leads to novel degradation during electrophoresis.
abstract: An opsonic molecule that is designated the third component of hagfish complement (HC3), and a fragment of HC3 known as HC3b have recently been identified in the hagfish, Eptatretus burgeri. These proteins were purified from plasma and generated a set of several bands and/or smears during SDS-PAGE under standard, non-reducing conditions. Two-dimensional electrophoretic analysis of the proteins under non-reducing and reducing conditions revealed the breakdown of polypeptides at the site of a thioester bond and the concomitant partial release of a split product, depending on the weak covalent or non-covalent association of polypeptide chains, in a large fraction of molecules of HC3 during SDS-PAGE. Moreover, the heterogeneity of HC3b can be ascribed to the different configurations of subunits. A similar phenomenon was not observed in the case of lamprey C3, even though breakdown of polypeptides at a thioester bond did occur in some molecules.
authors.affiliation: Department of Health Science, Faculty of Human Life and Environmental Science, Hiroshima Women's University, Japan. fujii@hirojo-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Fujii
authors.forename: S
authors.initials: S
authors.lastname: Kunisada
mesh_terms: D000818:Animals; D003176:Complement C3 / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D003165:Complement System Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004220:Disulfides; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D006196:Hagfishes / Q000276:immunology*; D007122:Immunoelectrophoresis; D007798:Lampreys; D011487:Protein Conformation
chemical_list: D003176:Complement C3; D004220:Disulfides; D003165:Complement System Proteins