The acid lability of the glycosidic bonds of L-iduronic acid residues in glycosaminoglycans.
Heparan sulphate, heparin and dermatan sulphate were hydrolysed in 0.5M-H2SO4 at 100 degrees C. At intervals portions of the hydrolysate were removed and treated with HNO2 at pH 4.0 to cleave the glycosidic bonds of the N-unsubstituted hexosamine residues and to convert both free and combined hexosamines into anhydrohexoses. These hydrolysis/deamination mixtures were reduced with NaB3H4 and analysed by radiochromatography for alpha-L-iduronosylanhydrohexose, beta-D-glucuronosylanhydrohexose, and the free uronic acids and anhydrohexose. These data gave a kinetic profile of the cleavage of the alpha-L-iduronosyl and the beta-D-glucuronosyl bonds in these glycosaminoglycans. The beta-D-glucuronosyl bonds showed the expected resistance to acid hydrolysis, but the alpha-L-iduronosyl bonds were found to be as labile to acid as some neutral sugar glycosides. This unusual lability of alpha-D-iduronosyl-anhydromannitol and beta-D-glucuronosylanhydromannitol. The procedures used to follow the kinetics of glycosaminoglycan hydrolysis can also be sued to obtain quantitative analyses of L-iduronic acid, D-glucuronic acid and hexosamine in these polymers.
D055598:Chemical Phenomena; D002621:Chemistry; D002807:Chondroitin / Q000031:analogs & derivatives; D002854:Chromatography, Paper; D003641:Deamination; D003871:Dermatan Sulfate; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D006868:Hydrolysis; D007067:Iduronic Acid / Q000032:analysis*; D009005:Monosaccharides / Q000032:analysis; D014574:Uronic Acids / Q000032:analysis*
D002807:Chondroitin; D003871:Dermatan Sulfate; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D007067:Iduronic Acid; D009005:Monosaccharides; D014574:Uronic Acids