Mucopolisacáridos

Mucopolisacáridos, also known as glycosaminoglycans or GAGs, are long unbranched polysaccharides consisting of repeating disaccharide units. Each disaccharide unit is composed of a hexosamine and a hexose or a uronic acid. The hexosamine can be glucosamine or galactosamine, and the hexose can be glucose or galactose. The uronic acid can be glucuronic acid or iduronic acid. GAGs are highly negatively charged due to the presence of sulfate and carboxyl groups, which allows them to bind large amounts of water and form a gel-like matrix. This property is crucial for their roles in the body.

These molecules are found in various tissues and play vital roles in biological processes. For instance, hyaluronic acid, a non-sulfated GAG, is a major component of connective tissues, synovial fluid, and the vitreous humor of the eye, providing lubrication and shock absorption. Chondroitin sulfate is abundant in cartilage, bone, and skin, contributing to their structural integrity and resilience. Heparan sulfate and heparin are found on the surface of cells and in the basement membrane, involved in cell signaling, growth factor binding, and anticoagulation (in the case of heparin). Dermatan sulfate is present in skin, blood vessels, and heart valves, contributing to their mechanical strength.

The synthesis and degradation of GAGs are tightly regulated processes. Deficiencies or abnormalities in GAG metabolism can lead to a group of genetic disorders known as mucopolysaccharidoses. These conditions are characterized by the accumulation of undegraded GAGs within cells, leading to a range of symptoms affecting multiple organ systems, including skeletal deformities, intellectual disability, and organ enlargement.