Collagen Biosynthesis


- Discussion:
    - biosynthesis of collagen is initiated w/ osteoblasts;
    - these intracellular events involve protein synthesis on endoplasmic reticulum to form 3 polypeptide chains, which make up protocollagen;
    - protocollagen is hydroxylated to form procollagen, which is glyco-sylated at the endoplasmic reticulum;
         - degree of hydroxylation of the lysine residue is important in that it will determine the number of crosslinks and therefore strength of the 
              collagen;
    - procollagen is converted to a triple helix before secretion from cell by microtubules;
    - procollagen helices are actually longer than collagen molecules owing to amino-terminal and carboxy-terminal endpieces that keep collagen
         soluble while inside the cell;
         - intracellular processes require more than eight enzymes, result in over l50 modifications of each chain, and alter one-tenth of the amino 
              acids;
    - once the osteoblasts secretes procollagen, a procollagen peptidase splits off the terminal endpieces, and polymerization and maturation 
         naturally follow;
    - covalent bonds are formed between the adjacent collagen molecules both within microfibrils and between adjacent microfibrils;
         - these crosslinks determine maximal tensile strength of tissue collagen & its subsequent solubility and thus extractability



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, September 13, 2011 1:12 pm