In a previous paper, we report a preliminary DSC study on bovine (BSA)
and human (HSA) serum albumins. However, at accurate HPLC analysis th
e commercial proteins show three peaks: Fraction V-I, probably globuli
ns (as declared by the producers), Fraction V-II (about 15-18% of the
product) and Fraction V-III that represents pure BSA or HSA. A hypothe
sis is that the Fraction II is a covalent dimer, or trimer or a mixtur
e of both, generated during the scalf-life of the commercial product.
Denaturation enthalpies of the purified Fraction V-III and Fraction V-
II of BSA, have been determined calorimetrically, at changing the pH,
and the results of both compared with those obtained on the untreated
protein. Few calorimetric experiments have been also carried on a BSA
monomer derivative with sulphidril group protected. Computer program h
ave been developed for the deconvolution of exo- and endothermic effec
ts and for the analysis of thermal denaturation profiles.