The primary function of keratins is to protect epithelial cells from mechanical and non-mechanical stresses that could cause cell death [2]. Additional functions of keratins include cell signalling, stress response and apoptosis. Keratin is generally considered to be single substance, but it is a mixture of proteins and enzymes. Other characteristics of keratin include indigestibility to pepsin/trypsin and also to dilute acids, alkalis, water and organic solvents. Keratins are, in general, insoluble in salt solutions but can be made soluble in the presence of urea and other denaturing agents.