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 '
The Keg of Nails 2014. Cincinnati leads the series 30–22–1. The Keg of Nails The Keg of Nails is a traveling trophy continuously-awarded to the winner of the American college football rivalry game between the Cincinnati Bearcats and Louisville Cardinals. The rivalry has stretched over the span of four conferences from the Missouri Valley Conference, to the Metro Conference to Conference USA, and more recently in the Big East Conference, which in 2013 was renamed to the American Athletic Conference. It is believed to be the oldest rivalry for the Louisville football team and the second oldest for Cincinnati, only behind the annual game