Heat Denaturation of Bovine Serum Albumin. I. Analysis by Acrylamide-gel Electrophoresis

Heat denaturation of bovine serum albumin (BSA) was studied at pH 8.9 in the temperature range 55-85°C. It was shown visually how various denatured-forms of BSA were produced. Depending upon the heating temperature and heating time, the number of discrete zones increased up to 6. The number did not exceed 6, but the next step was the broadening of the zone and the appearance of the tailing. Changes in the percent composition of each component were analyzed as a function of heating temperature and heating time. It was shown that (a) the mechanism of heat denaturation differs at the initial stage and at following stages, and that (b) some fraction of BSA is not denatured. A minor component 1 " was formed under some limited conditions. Effect of anti-denaturant was studied. The denaturation in distilled water was studied; it was found that only the native form was soluble and aggregates were precipitated. Present results were compared with those by Warner and Levy and by Stokrova et al. An attempt was made to assign present discrete zones to components postulated by them