EFFECT OF ADDITIVES ON REFOLDING OF A DENATURED PROTEIN

Denatured lysozyme was refolded by a dilution method. The refolding yi eld depended greatly on the lysozyme concentration in the refolding mi xture. When the concentration of denatured lysozyme was 0.02 g/L, the refolding yield was as high as 60%. However, when the concentration of denatured lysozyme was 0.2 g/L, the refolding yield was as low as 10% due to the formation of aggregates. To prevent the formation of aggre gates and to increase the refolding yield ata low cost, inexpensive ad ditives were screened. The addition of acetone, acetoamide, or urea de rivatives was very effective for improving the refolding yield. To cla rify why the addition of acetoamide in the refolding mixture improved the refolding yield at the high lysozyme concentration, the time cours es of the concentration and the average diameter of the aggregates in the refolding mixture were monitored by the dynamic light scattering m ethod. The experimental results showed that acetoamide played a role i n preventing the formation and growth of aggregates and secondary aggr egation between the lysozyme aggregates.