Collagen is the most common protein found in the human body. It is the main component of connective tissue and is the most abundant protein in mammals, making up 25-35 percent of total protein.
COLLAGEN is found in:
· hard tissue (ligaments, tendons)
· soft tissue (skin, intestine)
· structural tissue (bone, inter-vertebral disc)
The production of collagen in our body reduces as we age. The reduction of body collagen is at a rate of about 1.5 % per year from the age of 25. For example, when we reach 45 years of age, our body will have lost around 30% of its collagen content.
Collagen is a family of fibrous proteins having high tensile strength and, in mammals, accounts for around 30% of total protein mass. Collagen is a family of more than twenty distinct types based on the arrangement of the polypeptide chains that constitute each type, their biological function, morphological and pathological characteristics. Collagen types are made by a variety of different cells within the body. Importantly, the main helical portion of collagen varies little in different mammalian species.
The basic structural unit of collagen is tropocollagen, which consists of three amino acid strands intertwined in a helical fashion and each around 1,000 residues long. Collagen is unusually rich in glycine. Nearly every third residue is glycine. Glycine is a small amino acid which allows close packing of the triple stranded helix.
With three polypeptide chains, two of them referred to as α1 and the third referred to as α2. Type I Collagen forms the majority of connective tissue, both soft (skin, tendon, cornea) and hard (bone and dentine).
Type II Collagen is the major collagen of cartilage, inter-vertebral discs and vitreous bodies and comprises three α1 chains.
Type III Collagen comprises three α1 chains and is found in fetal skin, wounds, certain tumors, and blood vessels (tunica externa)