Glycosaminoglycans (GAGs) and Related Polysaccharides

Vocabulary flashcards covering GAGs, their components, related polysaccharides, and key concepts from the notes.

Glycosaminoglycans (GAGs)

Heteropolysaccharides composed of repeating disaccharides of an amino sugar and a uronic acid; negatively charged, providing slippery action and shock absorption in tissues (e.g., mucous, synovial fluid, vitreous humor, extracellular matrix).

Hyaluronic acid

GAG with repeating units of N-acetylglucosamine and D-glucuronic acid; non-sulfated; present in synovial fluid and vitreous humor; functions as a lubricant and shock absorber.

Chondroitin sulfate

GAG with repeating units of N-acetylgalactosamine and D-glucuronic acid; sulfated; present in cartilage; involved in tissue structure and processes such as cell migration and wound repair.

Dermatan sulfate

GAG with repeating units of N-acetylgalactosamine and L-iduronic acid; sulfated; found in skin and valves; contributes to shape and structure.

Heparin

A highly sulfated GAG with repeating units including glucosamine and uronic acids; well known anticoagulant.

Heparan sulfate

GAG with repeating units of glucosamine and iduronic/glucuronic acids; located on basement membranes; provides negative charge and mediates attachment of lipoprotein lipase to capillary endothelium.

Keratan sulfate

GAG with repeating units of N-acetylglucosamine and galactose; sulfated; lacks uronic acid; found in cornea, cartilage, skin, blood, and kidney.

Agar

Heteropolysaccharide made of glucose and galactose; used as a bacterial culture medium.

Agarose

Polysaccharide composed of galactose and anhydrogalactopyranose; used for protein and nucleic acid electrophoresis.

Pectin

Polysaccharide rich in galacturonic acid; used in foods as a gelling agent and as dietary fiber.

Glycemic index (GI)

A value used to measure how much a carbohydrate-containing food raises blood glucose; assigns a number to foods based on glycemic response.

Proteoglycan

A macromolecule with a core protein bearing glycosaminoglycan chains; carbohydrate content predominates (>95%).

Glycoprotein

A protein with attached carbohydrate groups; the protein portion is dominant (often >95%), with relatively smaller carbohydrate content.