Stopped-flow studies of the N ⇌ F transition in serum albumin

Abstract Stopped-flow studies of the refolding of iodoacetamide-blocked bovine serum albumin from the acid unfolded “F” state have been performed. If the protein is incubated with low concentrations of perchlorate anion then the refolding kinetics follow a simple first-order process. The dependence on pH of both the amplitude of the observed transients and the measured rate constants indicates that the N ⇌ F transition is highly cooperative. The results are consistent with the postulated multidomain structure of albumin which has been developed as a result of both sequence work and a variety of physical studies.