Molecular Weight of Ovalbumin and of Bovine Serum Albumin in Urea Solution

SINCE 1902, when Ramsden 1 described the effects of urea on “proteids”, there has been much speculation regarding the molecular weights of proteins in urea solution. Some workers have claimed that aggregation does not take place in the urea denaturation of ovalbumin and bovine serum albumin. In spite of this, it is well known that their urea solutions frequently form gels when the protein concentration is high. Recently, Kauzmann et al. 2,3 have studied the viscosity changes accompanying the urea denaturation of these proteins and the gelling time for ovalbumin. Under certain conditions an aggregation dependent upon concentration occurred, and this was interpreted in terms of hydrogen bonding and inter-molecular disulphide bonds (the latter through the —SS— and —SH exchange reaction of Huggins, Tapley and Jensen 4 ).