FIGURE 44.3.. Degradation of chondroitin/dermatan sulfates (CS/DS) and keratan sulfate (KS).

FIGURE 44.3.

Degradation of chondroitin/dermatan sulfates (CS/DS) and keratan sulfate (KS). (Left) Only DS degradation is shown. After removal of sulfated iduronic acid in two steps, further sequential degradation can proceed by two different routes. One route (straight down) uses GalNAc-4-SO4 sulfatase followed by cleavage with β-N-acetylhexosaminidase A or B. The other route uses only β-N-acetylhexosaminidase A, which is one of the few exoglycosidases that can cleave sulfated amino sugars at low pH. These two routes of sequential degradation also work in CS degradation. (Right) Degradation of KS. Sequential degradation of KS occurs from the nonreducing end like the degradation of DS and CS. The terminal GlcNAc-6-SO4 can be cleaved sequentially by a sulfatase and then by β-N-acetylhexosaminidase A or B, or, alternatively, β-N-acetylhexosaminidase A can cleave GlcNAc-6-SO4 directly at low pH.

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From: Chapter 44, Genetic Disorders of Glycan Degradation

Cover of Essentials of Glycobiology
Essentials of Glycobiology [Internet]. 4th edition.
Varki A, Cummings RD, Esko JD, et al., editors.
Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 2022.
Copyright © 2022 The Consortium of Glycobiology Editors, La Jolla, California; published by Cold Spring Harbor Laboratory Press; doi:10.1101/glycobiology.4e.44. All rights reserved.

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