Favourable interaction between heavy and light chains arrests the undesirable oligomerization of heavy chains in the refolding of denatured and reduced immunoglobulin G.

Abstract

Recently we developed a slow dialysis method that effectively refolds denatured and reduced immunoglobulin G (IgG) [Maeda, Ueda and Imoto (1996) Prot. Engng 9: 95-100]. This method allows both individual and simultaneous refolding of denatured and reduced H and L chains. Analysis by SDS-polyacrylamide gel electrophoresis revealed that some oligomers were formed through disulfide bonds when H chains were refolded individually. It was also shown that the extent of IgG obtained by rejoining the mixture of refolded H and L chains which had been refolded individually was similar to that obtained by refolding denatured and reduced whole IgG. The results indicated that a favourable interaction between H and L chains prevented formation of H-chain oligomers to yield intact IgG. The present results suggest a mechanism whereby individually folded chains might associate to form IgG molecules in vivo.