Keratin Keratin Keratin () is one of a family of fibrous structural proteins. It is the key structural material making up hair, horns, claws, hooves, and the outer layer of human skin. Keratin is also the protein that protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin derives from Greek ' from '
Major basic protein MBP does not bind either calcium or any of the other carbohydrates that this family recognize. Instead, MBP recognises heparan sulfate proteoglycans. Two crystallographic structures of MBP have been determined. Major basic protein has been shown to interact with Pregnancy-associated plasma protein A. arylsulfatase Major basic protein Eosinophil Major basic protein, often shortened to Major basic protein (MBP) (also called Proteoglycan 2(PRG2)) in humans is encoded by the "PRG2" gene. The protein encoded by this gene is the predominant constituent of the crystalline core of the eosinophil granule. High levels of the proform of this protein are also present in