Exendin-4 is a polypeptide composed of 39 amino acids, and its structure is thought to resemble a random coil chain. The short-range local interactions of a polypeptide influence the conformational preferences of its amino acid chain. In general terms, it is well established that the partial double bond character of a peptide bond gives rise to its planar structure, and free rotation is restricted about this bond. We hypothesise that with sufficient thermal energy and free volume present in the system, two local motions could take place for exendin-4, which would give rise to the β-relaxation process: (1) local side chain rotations, and ( ) local rotation about two single bonds. Given that the amino acids of the exendin-4 polypeptide chain are linked by peptide bonds, rotational freedom arises from the single bonds between an amino group and the α-carbon atom and the carbonyl group of the peptide backbone. However, the rotation of these bonds are limited by steric hindrance. Based on the chemical structure of the exendin-4 this polypeptide can act as a hydrogen bond acceptor via its carbonyl groups (-C=O) or as a hydrogen bond donor via its amine group (-NH), and its hydroxyl groups (-OH) can act as both the hydrogen bond donor or acceptor. The