Comparisons between the structure and function of collagen and insulin.

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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.

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The collagen polypeptide contains nearly one-third glycine, every third amino acid is glycine, and all the other amino acids are mostly either proline or hydroxyproline. Some the amino acids form a ring to force to become a triple helix and stop it from forming a secondary structure where as insulin is a chain and does not need to do this, the structure of collagen can be changed in diseases like scurvy, which is a lack of ascorbic acid, a cofactor in the hydroxylation of proline, an amino acid present in collagen.

As collagen is a very strong structural protein ...

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