Thermodynamic stability of ribonuclease B

The thermodynamic stability of pancreatic ribonuclease B (RNase B), which p ossesses identical protein structure of pancreatic ribonuclease A (RNase A) , but differs by the presence of a carbohydrate chain attached to Asn 34, w as studied by means of differential scanning calorimetry (DSC) at different pH conditions. The comparison between the two proteins has shown a little but significant stabilization of RNase B with respect to the unglycosylated one at pH values higher than 7.0. The thermodynamic analysis reveals the c arbohydrate moiety to have a small stabilization effect of 3 kJ mol(-1) at pH 8.0 and 63%C on the protein.