FAVORABLE INTERACTION BETWEEN HEAVY AND LIGHT-CHAINS ARRESTS THE UNDESIRABLE OLIGOMERIZATION OF HEAVY-CHAINS IN THE REFOLDING OF DENATURED AND REDUCED IMMUNOGLOBULIN-G

Recently we developed a slow dialysis method that effectively refolds denatured and reduced immunoglobulin G (IgG) [Maeda, Ueda and Imoto (1 996) Prot. Engng 9: 95-100]. This method allows both individual and si multaneous refolding of denatured and reduced H and L chains. Analysis by SDS-polyacrylamide gel electrophoresis revealed that some oligomer s were formed through disulfide bonds when H chains were refolded indi vidually. It was also shown that the extent of IgG obtained by rejoini ng the mixture of refolded H and L chains which had been refolded indi vidually was similar to that obtained by refolding denatured and reduc ed whole IgG. The results indicated that a favourable interaction betw een H and L chains prevented formation of H-chain oligomers to yield i ntact IgG. The present results suggest a mechanism whereby individuall y folded chains might associate to form IgG molecules in vivo.