Globular protein

Globular proteins are one of two types of proteins, the other being Fibrous proteins. Globular proteins have a compact and relatively spherical structure. Globular proteins are soluble in water and tend to be involved in metabolic functions, as opposed to fibrous proteins which tend to have a structural role. The polypeptide chain of a globular protein can be folded into regions of α-helical or β-sheet structures forming the secondary structure of the protein. The secondary structure can be majoritively α-helical, majoritively β-sheet or a combination of both the structures. These secondary structures are then folded on one another to form the globular tertiary structure of the protein. The α-helix and β-sheet regions contain random coils forming irregular structured regions which allow for the polypeptide chain to fold in a unique way. This means that every globular protein has a unique tertiary structure which is specific to the function of that protein.

Common globular proteins include haemoglobin, myoglobin, immunoglobin and insulin.