Chemical Effects of γ-Irradiation of Aqueous Solutions of Heparin and Keratan Sulphate

During γ-irradiation of dilute aqueous solutions of heparin and keratan sulphate, acid and reducing products are formed, mainly as a result of attack by OH radicals. Depolymerization to give lower dextrins also occurs without loss of sulphate groups, which results in a decrease in the dye binding ability of the polyanion. Pulse radiolysis was used to measure the rate constants for attack by OH radicals (k₂=4.7× 10⁸ M⁻¹ sec⁻¹) and e_ aq⁻ (k₂=3.0× 10⁷ M⁻¹ sec⁻¹). Oxygen exerts a protective effect which can be accounted for by the scavenging reaction e_ aq⁻+ O₂→ O₂⁻.