Excluded volume and viscosity effects of crowding agents that mimic crowded conditions in
vivo on “classical” burst phase folding kinetics of cytochrome c are assessed in vitro. Upon
electron transfer-triggered folding of reduced cytochrome c, far-UV time-resolved circular
dichroism (TRCD) is used to monitor folding under different conditions. Earlier work has
shown that folding of reduced cytochrome c from the guanidinium hydrochloride-induced
unfolded ensemble in dilute phosphate buffer involves kinetic partitioning: one fraction of …