DEPOLYMERIZATION OF HYALURONIC-ACID BY D-FRUCTOSE 6-PHOSPHATE

Depolymerization of hyaluronic acid obtained from Streptococcus zooepi demicus by D-fructose 6-phosphate was investigated for characterizatio n of reducing sugar-mediated degradation of biopolymers under physiolo gical conditions. The extent of depolymerization was monitored by the decrease of viscosity of a reaction mixture containing 1.0% hyaluronic acid, D-fructose 6-phosphate, and 1.0 x 10(-2) mm of Cu2+ in phosphat e buffer, pH 7.4. It was found that the depolymerization of hyaluronic acid was dependent on the concentration of the reducing sugar and was specifically accelerated by the presence of Cu2+. The reaction was fo und to be significantly inhibited by catalase, superoxide dismutase (S OD), 1,2-dihydroxybenzene 3,5-disulfonic acid (Tiron), and chelating a gents such as EDTA and diethylene triamine pentaacetic acid (DETAPAC), although the inhibition by SOD was low. Almost the same depolymerizat ion rates were observed in hyaluronic acid preparations of different m olecular weight (1.1 x 10(6), 8.8 x 10(5), and 6.8 x 10(5)). The rates , however, were different for hyaluronic acids obtained from S. zooepi demicus, rooster comb, and umbilical cord. It was concluded that depol ymerization of the polysaccharide was caused by active oxygen species generated by the autoxidation Of D-fructose 6-phosphate in the presenc e of Cu2+, in a mechanism similar to that previously reported for the degradation of DNA and inactivation of virus in vitro.