D-Arabinose

`unsulfonated 

`not covalently attached to proteins 

`serves as a lubricant and shock absorber 

found in synovial fluid in joints, vitreous humor of the eye, umbilical cord and loose connective tissue

`most abundant glycosoaminoglycans in the body

`cartilage, tendons, ligaments, aorta 

`bind collagen tightly and holds fibers in tight 

found in skin, blood vessels and heart valves

`very heterogeneous GAG

`cartilage and cornea

`the only intracellular GAG

`component of mast cells that line the arteries and serves as an anticoagulant