Chondroitin sulfates, structure, enzymic

Fig. 4.1.1 Structure of chondroitin sulfate. Cleavage sites for lysosomal enzymes are also indicated (arrows). MPS Mucopolysaccharidosis...

H13. Hoffman, P., Linker, A., Lippman, V., and Meyer, K., The structure of chondroitin sulfate B from studies with Flavobacterium enzymes. /. Biol. Chem. 235, 3066-3069 (I960). 

Heparin and hyaluronic acid will not act as acceptors for the enzyme (El, J17), whereas chondroitin 4-sulfate is at best a very poor acceptor (El, J17). The Enzyme Nomenclature Handbook (E4) quotes two sul-fatotransferases concerned with heparan sulfate structures desulfato-heparin sulfatotranferase (EC 2.8.2.S) and heparan sulfate sulfatotransferase (EC 2.8.2.12), but the contents of the relevant references quoted in the Handbook (El and S55, respectively) do not permit any distinction between the two supposed enzymes, nor do the reports discussed... 

Oligosaccharides (mostly DP 2-6) released by various enzymic digestions of hyaluronic add were derivatized with l-(4-methoxyphenyl)-3-methyl-5-pyrazolone (to give u.v.-absotbingderivatives of an uncharacterized structure) for reversed-phase h.p.lc. analysis. Oligosaccharides from the enzymic digestion of chondroitin sulfate and heparin were examined by ion-pair reversed-phase h.p.l.c. - electrospray m.s. analyses. ... 

Gal( l-4)Xyl/i-Ser. Constitutes the core structure of proteoglycans, like heparan and chondroitin sulfate, which are the principal components of extracellular matrix. They are implicated in many biological processes like cell adhesion, enzyme inhibition, embryonic development, and blood coagulation... 

Histochemical techniques for detecting substrate before and after enzyme treatment are extremely useful in studies on cellular structure. One of the oldest histochemical tests utilized saliva to identify suspected glycogen or starch. More definitive results are obtained when thin sections of a tissue are incubated in a buffered solution of purified amylase and stained for poly-utc-glycols. Material stained by periodic acid-Schiff reagent in the control, but not in the section exposed to amylase, is assumed to be glycogen or starch. Two more of the numerous histochemical techniques associated with localization of substrate are—using hya-luronidase to locate hyaluronic acid and chondroitin 4- and 6-sulfates (179) and using neuraminidases to locate sialomucins (180). By use of electron microscopy in combination with the histochemical technique subcellular localization can be obtained. 

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