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Chondroitin and Keratin Sulfate



- Discussion:
    - two major glycosaminoglycans w/ in cartilage ground substance consist of chondroitin sulfate and keratan sulfate;
    - both of these substances are covalently attached to the core protein of proteoglycan;
    - their concentration and distribution w/ in matrix vary considerably according to age, type of cartilage, & morphological location within 
           the tissue;
           - ratio of chondroitin sulfate to keratin sulfate:
                  - infant: 12 to 1
                  - adult: 2 to 1
                  - osteoarthritis: 10 to 1
    - chondroitin sulfate:
         - N-acetyl galactosamine alternates w/ glucuronic acid to form disaccharide repeating unit of polymer;
         - chondroitin sulfate consists of a chain of about 40 repeating units of N-acetyl chondrosine sulfate w/ about about 80 anionic charges;
         - there are about 100 chondroitin sulfate glycosaminoglycan chains per proteoglycan subunit;
         - chondroitin sulfate is the most prevalent of the glycoaminoglycan in cartilage:
                - concentration of chondroitin-4 sulfate steadily decreases w/ age;
                - chondroitin-6 sulfate concentration increases w/ older age;
    - keratan sulfate:
         - disaccharide repeating unit consisting of N-acetyl glucosamine alternating w/ galactose;
         - keratan sulfate has variable chain length & variable degree of sulfonation;
         - present in low levels in fetal & newborn cartilage;
         - concentration rises w/ maturation upto 55% of total glycosaminoglycan content of the tissue;
         - of note, Morquio's Syndrome is a disorder characterized by excessive accumulation of keratin sulfate in the tissues



Synthesis of chondrocytic keratan sulphate-containing proteoglycans by human chondrosarcoma cells in long-term cell culture.

Effect of hyaluronic acid/chondroitin sulfate on healing of full-thickness tendon lacerations in rabbits.

Characterization of aggregating proteoglycans from the proliferative, maturing, hypertrophic, and calcifying zones of the cartilaginous physis.