Proteins are large size molecules (macromolecules), polymers of structural units called amino acids. A total of 20 different amino acids exist in proteins and hundreds to thousands of these amino acids are attached to each other in long chains to form a protein. Amino acids can be released from proteins by hydrolysis. (Hydrolysis is the cleavage of a covalent bond by the addition of water inadequate conditions. Open access is a set of principles and a range of practices through which research outputs are distributed online, free of cost, or other access barriers. With open access strictly defined, or libre open access, barriers to copying or reuse are also reduced or removed by applying an open license for copyright.