Keratin reactivity depends on a number of factors. The main beingits chemical composition, morphological structure and also the character of intermolecular bonds and active keratin groups. Keratin reactivity is also influenced by its solubility, water susceptibility, adhesion to various substrates and mechanical properties [14]. The above factors depend on the hydrogen, ionic and covalent bonds present in the protein. One of keratin’s major influences is making hydrogen bonds with surrounding water molecules. The energy of hydrogen bonds is lower than that of ionic or covalent bonds, but higher than the energy of hydrophobic influences. Hydrogen bonds can be found between =NH and ≡C−OH groups. The presence of various groups in keratin structure enable it to participate in various processes. Figure 3 presentsthe possible chemical modifcations of proteins, including keratin.