Figure 3.

Bi-substrate reaction of XOD-mediated hydroxylation of xanthine and 6MP. The reaction mixture comprised of 1 ml of 0.2 M, sodium phosphate buffer pH 7.4 containing 10 μM of both xanthine and 6MP. The reaction was initiated by the addition of 2.8 U/ml of bovine XOD and observed for 20 min.