What Are the Differences Between Fibrous and Globular Proteins?

Globular proteins are spherical, elliptical or oval in shape and soluble in water, acids and bases, while fibrous proteins are not soluble, except in strong concentrations of acid and alkali. Fibrous proteins are one of three types of scleroprotein that make up connective tissue, bone matrices, tendons and muscle fiber. Fibrous proteins are more rod-like in structure.

The peptide sequence of scleroproteins can have limited residues which sometimes lead to the formation of secondary structures like a collagen helix. An easy way to differentiate the two is to picture their respective names; globular being glob-like and circular in structure, held together by a weak intermolecular hydrogen bond, whereas fibrous proteins look more similar to fibers of an elongated thread. They are asymmetrical in shape and are a peptide chain held together by very strong intermolecular hydrogen bonds. Insulin and egg albumin are two examples of globular proteins, while keratin, fibroin and collagen are some examples of fibrous proteins.

The word "protein" is derived from the Greek word "proteos," meaning first. Indeed, proteins are essential to the functions of all living beings and work to transport oxygen throughout the body, support mechanical movements and build necessary muscle, bone, skin and organ tissue.