14.23 Differentiate between globular and fibrous proteins.

Globular proteins

Fibrous proteins

It is usually soluble in water.

It is insoluble in water.

All enzymes are globular protein. Some hormones such as insulin are also globular protein.

Fibrous proteins are usually used for structural purposes. For example, keratin is present in nails and hair; collagen in tendons; and myosin in muscles.

The polypeptide chain in this protein is folded around itself, giving rise to spherical structure.

It is a fibre-like-structure formed by the polypeptide chain. These proteins are held together by strong and disulphide

bonds.

They are soluble in acids and bases.

They are insoluble in acids and bases.

Examples:- egg albumin, casein of milk.

Examples :- Silk, Skin, Wool.

They have weak intermolecular hydrogen bonding.

They have comparatively stronger intermolecular forces of attraction.

They have folded, ball like structure.

They have thread like structure.

Globular proteins are also called as

spheroproteins owing to their shape.

Fibrous proteins are also called as

scleroproteins.

More sensitive to the changes in pH, temperature etc.

Less sensitive to the changes in pH, temperature etc.