Chitin vs. Keratin — What's the Difference?

Chitin (C8H13O5N)n ( KY-tin) is a long-chain polymer of N-acetylglucosamine, an amide derivative of glucose. This polysaccharide is a primary component of cell walls in fungi, the exoskeletons of arthropods, such as crustaceans and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and skin of lissamphibians, making it the second most abundant polysaccharide in nature, behind only cellulose.

Keratin () is one of a family of fibrous structural proteins known as scleroproteins. α-Keratin is a type of keratin found in vertebrates.

A fibrous substance consisting of polysaccharides, which is the major constituent in the exoskeleton of arthropods and the cell walls of fungi.

A fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc.

A nitrogen-containing polysaccharide that is a tough, protective, semitransparent substance and is the principal component of arthropod exoskeletons and the cell walls of certain fungi.

Any of a class of filamentous proteins that are abundant in the cytoskeleton of vertebrate epithelial cells and are the main constituents of the outer layer of skin and tough epidermal structures such as hair, nails, hooves, feathers, and claws.

(carbohydrate) A complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans.

Material composed principally of keratin proteins.

A white amorphous horny substance forming the harder part of the outer integument of insects, crustacea, and various other invertebrates; entomolin.

(protein) The protein of which hair and nails are composed.

A tough semitransparent horny substance; the principal component of the exoskeletons of arthropods and the cell walls of certain fungi

A sulfur-containing fibrous protein constituting the main structural protein of hard epidermal tissues, such as horn, hair, feathers, nails, claws, hoofs, and the like. It is an insoluble substance, and, unlike elastin, is not dissolved even by gastric or pancreatic juice. By decomposition with sulphuric acid it yields leucine and tyrosine plus various other acid-stable amino acids. The amino acid composition varies, but it usually has a high percentage of cystine, which stabilizes and insolubilizes the protein by forming intrachain linkages. A softer form of keratin is present in the epidermis and whalebone. Called also epidermose.

A fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair feathers nails and hooves