Allopurinol and oxypurinol are hydroxyl radical scavengers.
Allopurinol is a scavenger of the highly reactive hydroxyl radical (k2 approx. 10(9) M-1 X s-1). One product of attack of hydroxyl radical upon allopurinol is oxypurinol, which is a major metabolite of allopurinol. Oxypurinol is a better hydroxyl radical scavenger than is allopurinol (k2 approx. 4 X 10(9) M-1 X s-1) and it also reacts with the myeloperoxidase-derived oxidant hypochlorous acid. Hence the protective actions of allopurinol against reperfusion damage after hypoxia need not be entirely due to xanthine oxidase inhibition.
D000493:Allopurinol / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003855:Deoxyribose / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D006878:Hydroxides; D017665:Hydroxyl Radical; D006997:Hypochlorous Acid / Q000378:metabolism; D007700:Kinetics; D010117:Oxypurinol / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D011743:Pyrimidines / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000378:metabolism
D005290:Ferric Compounds; D006878:Hydroxides; D011743:Pyrimidines; D017665:Hydroxyl Radical; D003855:Deoxyribose; D000493:Allopurinol; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide; D009195:Peroxidase; D014969:Xanthine Oxidase; D010117:Oxypurinol; D001205:Ascorbic Acid