Elastin since they become crosslinked into elastin fibres immediately after their synthesis by the cell and during their export into the extracellular matrix. Each tropoelastin consists of a string of 36 small domains, each weighing about 2 kDa in a random coil conformation. The protein consists of alternating hydrophobic and hydrophilic domains, which are encoded by separate exons, so that the domain structure of tropoelastin reflects the exon organization of the gene. The hydrophilic domains contain Lys-Ala (KA) and Lys-Pro (KP) motifs that are involved in crosslinking during the formation of mature elastin. In the KA domains, lysine residues occur as
Collagen a cofactor, a long-term deficiency in this vitamin results in impaired collagen synthesis and scurvy. These hydroxylation reactions are catalyzed by two different enzymes: prolyl-4-hydroxylase and lysyl-hydroxylase. Vitamin C also serves with them in inducing these reactions. In this service, one molecule of vitamin C is destroyed for each H replaced by OH. The synthesis of collagen occurs inside and outside of the cell. The formation of collagen which results in fibrillary collagen (most common form) is discussed here. Meshwork collagen, which is often involved in the formation of filtration systems, is the other form of collagen. All types of