Comparisons between the structure and function of collagen and Insulin
Insulin is a very important hormone and is also it is a fibrous protein, this means its properties are that it is extensible, strong and insoluble it is also a secondary structure which is made up of α helices and β sheets, where as collagen is a important structural protein found in animals which is a globular protein (a secondary structure bent and folded into spherical shapes) which is soluble which consists of a hydrophobic core which is surrounded by a hydrophilic external surface. An insulin molecule consists of 51 amino acids and three disulphide cross links which is made up of two separate polypeptide chains know as chain A and chain B. Polypeptide chain A contains 21 amino acids and polypeptide chain B contains 30 amino acids, they are joined tighter by three disulphide bridges two inter-chain disulphide bridges and one intra-chain disulphide bridges. The structure of insulin is a compact cylinder with the carboxyl of polypeptide chain B longer then the rest of the protein. Insulin contains many hydrophobic residues which together form a hydrophobic core where as a collagen molecule is a much larger structure, it consists of three polypeptide chains which each contain around 1000 amino acids which are coiled together to form a triple helix.