(b) Most globular proteins are denatured and lose their activity when briefly heated to 65 8C. However, globular proteins that c
ontain multiple disulfide bonds often must be heated longer at higher temperatures to denature them. One such protein is bovine pancreatic trypsin inhibitor (BPTI), which has 58 amino acid residues in a single chain and contains three disulfide bonds. On cooling a solution of denatured BPTI, the activity of the protein is restored. What is the molecular basis for this property?
The higher temperature is the factor which is responsible for the process of denaturation of proteins in which the breaking down of hydrogen, disulphide bonds and destabilization occurs. This process breaks up the bond between the polypeptides.
The bovine pancreatic trypsin inhibitor comprises of 58 amino acids this consists of the disulphide bonds which are destroyed on heating as a result of this the inhibitor becomes inactive. But on cooling it comes to the original form as the internal structure starts making hydrogen and disulphide bonds again. Thus the activity of the BPTI again gets restored.
