Proteoglycans –> Glycosaminoglycans

Hyaluronate

Uronic Acid: Glucuronic

Amino Sugar: N-Acetylglucosamine

Localization: Synovial fluid, vitreous humor, ECM of connective tissue, also found in neural tissues

Characteristics: Large polymers, lubricator and shock absorbing. Not covalently attached to proteins.

Beta linkages: beta-1,3

Chondoitin Sulfate

Uronic Acid: Glucuronic

Amino Sugar: N-Acetylgalactosamine sulfate

Localization: Important structural component of cartilage, bone, heart valves. Treatment of osteoarthritis.

Characteristics: Most abundant GAG. Found as proteoglycans.

Beta linkages: beta-1,3

Heparin sulfate

Uronic Acid: Iduronic acid sulfate and glucuronic acid

Amino Sugar: Glucosamine bis-sulfate (or glucosamine sulfate)

Localization: Basement membranes, components of cell surfaces

Characteristics: Contains higher acetylated glucosamine than Heparin. Blood anticoagulation. Found as proteoglycans.

Beta linkages: alpha-1,3

Heparin

Uronic Acid: Iduronic acid sulfate and glucuronic acid

Amino Sugar: Glucosamine bis-sulfate (or glucosamine sulfate)

Localization: Component of intracellular granules of mast cells lining the arteries of the lungs, liver and skin.

Characteristics: More sulfates than Heparan sulfates. Blood anticoagulation. Found as proteoglycans.

Beta linkages: alpha-1,4

Dermatan sulfate

Uronic Acid: Iduronic (some glucuronic)

Amino Sugar: N-Acetylgalactosamine sulfate

Localization: Skin, blood vessels, heart valves, tendons

Characteristics: Formerly called mucopolysaccharide. Found as proteoglycans.

Beta linkages: alpha-1,3

Keratan sulfate

Uronic Acid: None, but galacatose

Amino Sugar: N-Acetylglucosamine sulfate

Localization: Found in Bone, Cornea (I), and skeletal muscle (II). When in cartilage, aggregated with chondroitin sulfates.

Characteristics: Found as proteoglycans

Beta linkages: beta-1,4