Studies on plasma protein interactions in heat-induced gels by differential scanning calorimetry and FT-Raman spectroscopy

Protein–protein interactions during the heat-induced gelation of plasma proteins were investigated by means of differential scanning calorimetry (DSC) and FT-Raman spectroscopy. The deconvolution of DSC curves revealed a specific interaction between fibrinogen and albumin, which involved changes in disulphide bonds, buriedness of hydrophobic groups and β-sheet content, as described by FT-Raman spectroscopy. On the other hand, mixtures of albumin and globulins showed specific interactions involving disulphide bonds and hydrophobic residues to a lesser extent, which could be responsible of the distinct physical attributes between heat-induced gels formed from single fractions and mixtures previously reported. In addition, an inhibitory effect of albumin on globulin's aggregation was observed in mixtures when albumin was the dominant fraction, although no major structural changes were involved in this process.