Keratin sulfate, hyaluronic acid

Fig. 19 Structures of glycosaminoglycans (A) chondroitin-4-sulfate (B) heparin sulfate (C) dermatin sulfate (D) hyaluronic acid (E) chondroitin-6-sulfate (F) keratin sulfate. 

The effect of ascorbic acid on the production of proteoglycans is rather controversial. Edward and Oliver (1983) found that both hyaluronate and sulfated gly-cosaminoglycan synthesis by human skin fibroblasts was affected by vitamin C. Kao and coworkers (1990) found that ascorbic acid stimulates the production of glycosaminoglycans in cultured fibroblasts, whereas Pacifici (1990) observed that in chick chondrocyte cultures the secretion of keratin sulfate and chondroitin sulfate-containing proteoglycans was not affected by ascorbic acid in the culture medium. 

The GAGs contain specific sugars such as glucosamine sulfate, N-acetylglucosamine and glucosamine hydrochloride, all very able of attracting water. They form long chains of molecules that retain water, such as hyaluronic acid, keratin sulfate, heparin, dermatin, and chondroitin. 

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