Microcalorimetric study of human serum

It was established that albumin of donor blood serum denatures in two temperature ranges. It is shown that the first stage of denaturation with Td = 61.5 degrees C is dominant and corresponds to melting of regions not bound to fatty acids. The second stage with Td = 80 degrees C corresponds to melting of regions bound to fatty acids. Serum denaturation heat is equal to 20.2 J/g dry protein. A change in denaturation heat capacity is 0.21 J/(g.K). Analysis of thermal parameters of deconvolution peaks showed that albumin of donor blood serum is in a fatless state and its multiple binding centers are essentially free as compared with freshly isolated albumin and may play an important role in binding of ligands in vivo. The thermal parameters of denaturation of some important human blood serum proteins including gamma-globulins, transferrin ceruloplasmin and protease inhibitors were also determined.