Oxypurinol can slowly dissociate from the enzyme. Moreover, oxypurinol can fail to completely inhibit the oxidized form of xanthine oxidase in certain biologic milieus (as opposed to enzyme inhibition in simple solution), as shown by the recent work of Kelley et al (Kelley EE, Trostchansky A, Rubbo H, et al. Binding of xanthine oxidase to glycosaminoglycans limits inhibition by oxypurinol. J Biol Chem. 2004;279:37231-37234).
Please visit www.The-Rheumatologist.org to download a corrected version of the July issue under the “Download Issues” tab.
