EC Number   |
Reaction |
Reference |
|---|
    1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
a reaction mechanism for XDH is suggested in which an initial oxo rather than a hydroxo group and the sulfido ligand are essential for xanthine oxidation |
745069 |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
Acts on a variety of purines and aldehydes. The animal enzyme can be interconverted to EC 1.1.3.22 xanthine oxidase, the oxidase form. That from liver exists in vivo mainly in the dehydrogenase form, but can be converted into EC 1.1.3.22 by storage at -20°C, by treatment with proteolytic agents or organic solvents, or by thiol reagents such as Cu2+, N-ethylmaleimide or 4-hydroxymercuribenzoate. The effect of thiol reagents can be reversed by thiols such as 1,4-dithioerythritol. EC 1.1.1.204 can also be converted into EC 1.1.3.22 by EC 1.8.4.7 enzyme-thiol transhydrogenase (oxidized-glutathione) in the presence of the oxidized glutathione. In other animal tissues, the enzyme exists almost entirely as EC 1.1.3.22, but can be converted into the dehydrogenase form by 1,4-dithioerythritol. Formerly EC 1.2.1.37 |
- |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
catalytically labile Mo-OH oxygen forms a bond with a carbon atom of substrate, the Mo=S group of the oxidized enzyme becomes protonated to afford Mo-SH on reduction of the molybdenum center |
660378 |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
mechanism of conversion of dehydrogenase form to oxidase form |
659481 |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
reaction mechanism of XOR and binding modes of the substrate xanthine, overview. The oxidative hydroxylation of purine substrates takes place at the molybdenum center. Reducing equivalents introduced there are then transferred via two [2Fe-2S] centers to the FAD cofactor where reduction of the physiological electron acceptors occurs, NAD+ in the case of the dehydrogenase form, XDH, or O2 in the oxidase form, XO, of the enzyme occur |
715273 |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
reaction mechanism with substrate all-trans-retinol, overview |
704842 |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
reaction mechanism, The reaction is initiated by proton abstraction from the Mo-OH group by Glu730, the active-site base, followed by nucleophilic attack on the carbon to be hydroxylated, and hydride transfer to the Mo-S double bond. Suitable substrate orientation, overview. Arg310 is involved in stablizing the transition state in the course of nucleophilic attack, overview |
715157 |
| 1.17.1.4 | xanthine + NAD+ + H2O = urate + NADH + H+ |
the catalytic sequence of Rhodobacter capsulatus XDH is initiated by abstraction of a proton from the Mo-OH group by the highly conserved active site subunit B residue Glu730, followed by nucleophilic attack of the resulting Mo-O on the carbon center of the substrate (C-2 in hypoxanthine and C-8 in xanthine) and concomitant hydride transfer to the Mo-S of the molybdenum center, reaction and substrate binding mechanisms, overview |
704636 |
