Studies on Aggregation Interaction between Reduced‐Denatured Egg White Lysozymes during Refolding Procedure in Urea Solution

Abstract The aggregation interaction between reduced‐denatured egg white lysozymes during refolding procedure in urea solution was studied by means of reducing and non‐reducing protein electrophoreses. Results of non‐reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) of the supernatant and aggregate precipitate formed in refolding process show that except being refolded to native egg white lysozymes, the reduced‐denatured lysozymes can also form the aggregates with molecular weights (MW) being separately about 30.0 and 35.0 kD, while the reducing SDS‐PAGE and the refolding results in the presence of sodium dodecyl sulphate show that these aggregates are formed chiefly through the misconnection of disulfide bonds between the reduced‐denatured lysozymes, and the aggregate precipitates are formed through the non‐covalent interactions between the aggregates with molecular weight being about 30.0 kD. From the results of electrophoresis and size‐exclusion chromatographic analyses, it can be inferred that the aggregates with molecular weights being about 30.0 and 35.0 kD are bi‐molecular and tri‐molecular egg white lysozyme aggregates, respectively. And finally, a suggested refolding mechanism of reduced‐denatured egg white lysozymes in urea solution was presented.