A patient suffering from a combined deficiency of sulfite oxidase (sulfite dehydrogenase; sulfite:ferricytochrome c oxidoreductase, EC 1.8.2.1) and xanthine dehydrogenase (xanthine:NAD+ oxidoreductase, EC 1.2.1.37) is described. The patient displays severe neurological abnormalities, dislocated ocular lenses, and mental retardation. Urinary excretion of sulfite, thiosulfate, S-sulfocysteine, ta...

The catalytically essential persulphide groups at the molybdenum centres of xanthine oxidase and xanthine dehydrogenase are essential to interaction with arsenite (Edmonson et al., 1972; Cleere et al., 1974) Inhibition of xanthine hydroxylation may result from arsenite forming a complex with the persulphides and vicinal thiol groups (Massey & Edmonson, 1970). The NADH-dichlorophenol-indophenol ...

It is proposed, Phosphoribosyl Pyrophosphate (PRPP), (product of the pyrimidine biosynthesis key regulative enzyme Phosphoribosylpyrophosphate Synthase-1 (PRPS-1)), accelerates Epidermal Growth Factor (Egf) dependent cells proliferation. However, Egf or its fragments don't have direct impact on the PRPS-1. Reactive Oxygen Species, generated by purine catabolism regulative enzyme Xanthine Oxidor...

© 2013 Ashizawa and Shimo, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mechanism of Urinary Bladder Carcinogenesis Induced by a Xanthine Oxidoreductase...

Xanthine oxidoreductase (XOR) is a cytoplasmic molybdenum-containing oxidoreductase, catalyzing both endogenous purines and exogenous compounds. It is suggested that XOR in porcine hepatocytes catalyzes the N-oxide reduction of quinoxaline 1,4-di-N-oxides (QdNOs). To elucidate the molecular mechanism underlying this metabolism, the cDNA of porcine XOR was cloned and heterologously expressed in ...