Concentrations and partial volumes of proteins

The amount of egg albumin and bovine serum albumin in water has been studied as a function of temperature and time. The temperature selected for heating was 102 °C. The proteins appear to decompose above this temperature. The suitable length of time of drying is 24 h at 102 °C. Four modifications of the method of dry weight have been explored. Glass paper in the weighing bottle increases the area available for evaporation. The densities of solutions of egg albumin and bovine serum albumin have been measured at 30.00 °C as a function of concentration with a Mettler/Paar density meter and the apparent specific volumes calculated. The apparent specific volume of egg albumin is independent of concentration and is 0.7463 ± 0.00016. The apparent specific volume of bovine serum albumin is constant from zero concentration up to about 0.2 g/g of solution and in this concentration range the apparent specific volume is 0.7348 ± 0.0001. Beyond this concentration, in agreement with the results of Bernhardt and Pauly, the apparent specific volume drops sharply with increasing protein concentration.