MECHANISMS OF DENATURATION OF BOVINE SERUM ALBUMIN BY UREA AND UREA-TYPE AGENTS

The kinetics of the reaction of bovine serum albumin with urea and urea-type denaturants as studied by dilatometry, acrylamide gel electrophoresis and urea gel perturbation reveal the occurrence of parallel and consecutive reactions which generate different forms of denatured albumin as a function of the conditions employed. The initial fast reaction produces conformationally altered albumins which are converted by subsequent slower temperature- and concentration-dependent reactions to multiple forms of denatured albumins. The pH of the system has a profound influence on the denaturation process with the products formed at low pH differing markedly from those found at neutrality and at high pH. Reversibility studies employing thin-film dialysis revealed the coexistence of both water- and dilute salt-insoluble products. The products formed by the slow time-dependent reactions reflect the operation of sulfhydryl mediated intra- and interdisulfide exchange processes. © 1969.