By use of steady photo-irradiation in the system of riboflavin aqueous solution containing methyl-sulf-amino acid and superoxide dismutase (SOD) as competitive scavenger of O2, the rate constant of superoxide anion radi- cal(O2 ·)scavenged by (Amberacid-chitosan-complex with copper (II), ACCC) was determined as 1.26×109, ? 1.11×109 and 4.98×108 mol-1 s-1 dm3 under irradiation of 254nm, 365nm UV lights and sun light, respectively. The results also show that the scavenge rate of O2 · by ACCC reached 91%, which is about the same as with ? natural SOD (93%), and is far more higher than the O2 · scavenge rate with just amberacid or chitosan, which is ? only 2.6% and 5.8%, respectively.
