Abstract
The temperature dependencies of the optical rotation, light transmittance and viscosity of human serum albumin (HSA) solutions containing 2 M guanidine hydrochloride were investigated, in order to elucidate the gelation mechanism.
Unfolding of HSA molecules started at a certain temperature (Td) and phase separation occurred at a higher temperature (Ts) than the Td. The phase separation resulted in a heterogeneous, binary phase solution consisting of a fine coacervate particle phase and a dilute solution phase. At the phase separation point, there were more native state molecules than unfolded ones. No increase in viscosity was observed within the temperature range from the Td to the Ts. An apparent increase in viscosity started at the Ts, showing that network formation proceeded from the Ts. These results suggested that the network formation was due to crosslinking among dispersed coacervate particles in the dilute solution phase.
