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Treatment of Human Complement Components C4 and C3 with Amines or Chaotropic Ions
Author(s) -
ZABERN I.,
NOLTE R.,
VOGT W.
Publication year - 1981
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1981.tb00152.x
Subject(s) - chaotropic agent , chemistry , cleavage (geology) , ammonium , ammonium hydroxide , alternative complement pathway , biochemistry , hydroxide , peptide , complement system , chromatography , organic chemistry , biology , antibody , immunology , paleontology , fracture (geology)
Treatment of human components C4 and C3 with amines like hydrazine, ammonium hydroxide, and neutral ammonium salts or with chaotropic salts like KSCN und NaBr leads to complete loss of haemolytic activity. The pretreated components are however, still active in formation of soluble C3 convertases. This activity pattern is reminiscent of the activities of C4 and C3 that have been activated by cleavage in the fluid phase. Indeed, the antigenic properties of pretreated C4 and C3 are similar to soluble C4b and C3b. The polypeptide chain structure of pretreated C4 and C3, is, however, identical to that of the untreated components when investigated by SDS gel electrophoresis. Pretreatment even reduces greatly the susceptibility of C4 to cleavage by C1 and of C3 to cleavage by classical and alternative pathway C3 convertases. Pretreated components have lost the ability to combine with EAC1 and EAC142, respectively; this fact explains their failure to exhibit haemolytic activity. In serum, pretreated C4 and C3 are cleaved in a manner similar to C4b and C3b. Amines and chaotropic ions cause the same functional and structural alterations, which are best explained by assumption or a conformational change. A similar transformation can also occur in C4 and C3 during preparation or storage