Which of the following is the major proteoglycan of synol fluid?
Hyaluronic Acid A sulphate free mucopolysaccharide. It was first isolated from vitreous humour of eye. Later it was found to be present in synol fluid, skin, umbilical cord, haemolytic streptococci and in rheumatic nodule. It occurs both free and salt-like combination with proteins and forms so- called ground substance of mesenchyme, an integral pa of the gel-like ground substance of connective and other tissues. Composition: It is composed of repeating units of N-acetyl glucosamine and D-Glucuronic acid. On hydrolysis, it yields equimolecular quantities of D-Glucosamine, D-Glucoronic acid and acetic acid (Fig. 3.20). Functions: (See below under proteoglycans) Hyaluronidase: An enzyme present in ceain tissues, notably testicular tissue and spleen, as well as in several types of pneumococci and haemolytic streptococci. The enzyme catalyses the depolymerization of hyaluronic acid and by reducing its viscosity facilitates diffusion of materials into tissue spaces. Hence the enzyme, sometimes, is designated as spreading factor. Biomedical Impoance * The invasive power of some pathogenic organisms may be increased because they secrete hyaluronidase. In the testicular secretions, it may dissolve the viscid substances surrounding the ova to permit penetration of spermatozoa. * Clinically the enzyme is used to increase the efficiency of absorption of solutions administered by clysis.Ref: Textbook of Medical Biochemistry, Eighth Edition, Dr (Brig) MN Chatterjea, page no: 38
Chondroitin sulfate
Dermatan sulfate
Heparan sulfate
Hyaluronic acid
Metabolism of lipid