Collagen is the predominant protein in the animal body and constitutes approximately 30% of total protein (Birk & Bruckner, 2005; Unlua et al. 2014). It is an extracellular matrix protein that can interact directly or indirectly with cells to alter cellular activity. At least 27 different types of collagen have been identified, correspondingly referred to as types I to XXVII (Birk & Bruckner, 2005). Structure Collagen is characterized by a rod-like structure with a right-handed triple helix formed by three polypeptide chains with a left-handed helix. Although the triple helical structure is the main characteristic of collagen, some globular proteins are identified as collagen because of the repeating trilects and small triple helical rods (Prockop & Kivirikko 1995). Each polypeptide chain consists of repeating triplets, (Gly-XY), where X and Y are, with a high frequency, proline (Pro) and hydroxyproline (Hyp), respectively (Prockop & Kivirikko 1995; Ogawa et al. 2003). Glycine in every three amino acids is very essential. The small side chain of glycine allows the side chain of proline to...