[Structural transitions of bovine serum albumin detected during scanning calorimetry]

The calorimetry studies of temperature dependence of bovine serum albumin heat capacity for the temperature interval 20-150 degrees C and pH value varying from 4 to 9 were carried out. It is shown that in the pH range considered four types of denaturation curves differing in quantity and temperatures of endothermic pikes exist. The different types of the melting curves correspond to different types of protein domain structure. At 110-120 degrees C and pH greater than or equal to 5.6 the high temperature maximum is shown to exist. The later is supposed to be due not to BSA denaturation process but to cooperative destruction of postdenaturation remnants of the secondary protein structure.