Collagen is a fibrous protein that provides the structure of connective tissue such as skin, arteries, tendons, bones, teeth, and cartilage. Collagen is tough and has high tensile strength. Collagen protein comprises almost half of all of the protein in the body. Collagen production, supported by vitamin C, is also important for veins, heart valves, intervertebral discs, the cornea, and the lens of the eye. Collagen is a large molecule consisting of about one thousand amino acid residues.
Collagen is mostly composed of only two amino acids, glycine and hydroxyproline. The collagen molecule has a unique triple-helix configuration with three intertwined polypeptide chains. Collagen provides the organic matrix upon which bone minerals crystallize. Collagen glues cut skin together by forming a scar. This is why surgeons will often recommend higher levels of vitamin C supplementation after surgery to support increased collagen production. The collagen protein is invaluable in artery and capillary walls to provide the strength and flexibility needed to resist cardiovascular disease.
HOW COLLAGEN IS MADE
It is a major manufacturing effort for our bodies to produce collagen. First, procollagen is made with the two amino acids, glycine and proline, as shown in Figure 2-2. Vitamin C is used in making procollagen. The conversion of procollagen to collagen involves a reaction (hydroxylation) that substitutes a hydroxyl group, OH, for a hydrogen atom, H. The proline residues at certain points in the polypeptide chains are hydroxylated to hydroxyproline. The essential amino acid
Figure 2-2 Biosynthesis of collagen
lysine is hydroxylated to hydroxylysine, which is needed to permit the cross-linking of the triple helices of collagen into the fibers and networks of the tissues. One molecule of vitamin C is destroyed each time proline or lysine is hydroxylated. Lack of vitamin C can cause weak and brittle arteries and raise the risk of cardiovascular disease because of lowered collagen production.
Collagen and keratin, another fibrous protein, are responsible for the elasticity of skin. The degradation of collagen leads to wrinkles that can be caused by aging or smoking. These wrinkles are partly due to oxidative damage by free radicals.
As we age, collagen becomes more highly cross-linked and therefore more rigid. Injected collagen is used in cosmetic surgery, especially to thicken lips. Ferrous iron is required as a cofactor for collagen synthesis in the body. Vitamin C plays its role as an antioxidant to reduce the iron from its oxidized state. The iron can then go on as a cofactor to make more collagen.
Collagen is mostly composed of only two amino acids, glycine and hydroxyproline. The collagen molecule has a unique triple-helix configuration with three intertwined polypeptide chains. Collagen provides the organic matrix upon which bone minerals crystallize. Collagen glues cut skin together by forming a scar. This is why surgeons will often recommend higher levels of vitamin C supplementation after surgery to support increased collagen production. The collagen protein is invaluable in artery and capillary walls to provide the strength and flexibility needed to resist cardiovascular disease.
HOW COLLAGEN IS MADE
It is a major manufacturing effort for our bodies to produce collagen. First, procollagen is made with the two amino acids, glycine and proline, as shown in Figure 2-2. Vitamin C is used in making procollagen. The conversion of procollagen to collagen involves a reaction (hydroxylation) that substitutes a hydroxyl group, OH, for a hydrogen atom, H. The proline residues at certain points in the polypeptide chains are hydroxylated to hydroxyproline. The essential amino acid
lysine is hydroxylated to hydroxylysine, which is needed to permit the cross-linking of the triple helices of collagen into the fibers and networks of the tissues. One molecule of vitamin C is destroyed each time proline or lysine is hydroxylated. Lack of vitamin C can cause weak and brittle arteries and raise the risk of cardiovascular disease because of lowered collagen production.
Collagen and keratin, another fibrous protein, are responsible for the elasticity of skin. The degradation of collagen leads to wrinkles that can be caused by aging or smoking. These wrinkles are partly due to oxidative damage by free radicals.
As we age, collagen becomes more highly cross-linked and therefore more rigid. Injected collagen is used in cosmetic surgery, especially to thicken lips. Ferrous iron is required as a cofactor for collagen synthesis in the body. Vitamin C plays its role as an antioxidant to reduce the iron from its oxidized state. The iron can then go on as a cofactor to make more collagen.
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