Periodate oxidation of the d-glucuronic acid residues in heparan sulphate and heparin

Abstract

On oxidation with periodate at pH 7.0 and 37°, the uronic acid residues of heparan sulphate preparations were almost completely destroyed, whereas only 20% of those in heparin were susceptible to oxidation. At pH 3.0 and 4°, 30–40% of the uronic acid residues in heparan sulphates were destroyed, but very few in heparin. In all cases at pH 3.0 and 4°, the l-iduronic acid residues were resistant to oxidation, whereas a large proportion of the d-glucuronic acid residues were affected. However, a small but significant proportion of the d-glucuronic acid residues resisted oxidation. The initially periodate-resistant d-glucuronic acid residues were destroyed when alkali-treated oxyheparan sulphate was treated with periodate. When heparan sulphate and heparin derivatives containing mainly N-acetylated 2-amino-2-deoxy- d-glucose residues were treated with periodate at pH 3.0 and 4°, most of the d-glucuronic acid residues were destroyed, whereas the l-iduronic acid residues were resistant.