The activity of xanthine dehydrogenase in human postmortem tissues is surprisingly high in brain and heart; activity was found in most tissue samples, whereas many samples contained little or no oxidase activity. We have confirmed the high level of oxidase activity in liver in which tissue conversion of dehydrogenase to oxidase appears complete. We have also confirmed the virtual absence of eit...

BACKGROUND Metabolic engineering of Saccharomyces cerevisiae for xylose fermentation into fuel ethanol has oftentimes relied on insertion of a heterologous pathway that consists of xylose reductase (XR) and xylitol dehydrogenase (XDH) and brings about isomerization of xylose into xylulose via xylitol. Incomplete recycling of redox cosubstrates in the catalytic steps of the NADPH-preferring XR a...

BACKGROUND Current research into the mechanisms of organ atrophy associated with cancer cachexia have centred on the loss of skeletal muscle, as it is one of the most profound physical changes of the disease. However, many patients with cancer cachexia also experience significant atrophy of the heart. The mechanisms causing cardiac tissue wastage in cancer cachexia are largely unknown. However,...

2,5-Diaziridinyl-3-(hydroxymethyl)-6-methyl-1,4-benzoquinone (RH1) is a novel antitumor diaziridinyl benzoquinone derivative designed to be bioactivated by the two-electron reductase NAD(P)H:quinone oxidoreductase (NQO1) and is currently in clinical trials. NQO1 is expressed at high levels in many solid tumors. RH1 cytotoxicity has been shown previously to be NQO1-dependent. The purpose of this...

Saccharomyces strains engineered to ferment xylose using Scheffersomyces stipitis xylose reductase (XR) and xylitol dehydrogenase (XDH) genes appear to be limited by metabolic imbalances, due to differing cofactor specificities of XR and XDH. The S. stipitis XR, which uses both NADH and NADPH, is hypothesized to reduce the cofactor imbalance, allowing xylose fermentation in this yeast. However,...

Aldehyde oxidase (AOX) is a member of the xanthine oxidase (XO) family of molybdenum hydroxylase, iron-sulfur flavoproteins and is involved in the metabolism of a wide range of native and xenobiotic compounds. The potentially toxic reduced oxygen intermediates (ROI), hydrogen peroxide (H2O2) and superoxide anion (O2(.-)), are generated when reduced AOX becomes oxidized by molecular oxygen, rais...

BACKGROUND The aim of this study was to study the effects of gypenosides (GPS) on lowering uric acid (UA) levels in hyperuricemic rats induced by lipid emulsion (LE) and the related mechanisms. GPS are natural saponins extracted from Gynostemma pentaphyllum. MATERIAL AND METHODS Forty-eight male SD rats were randomly divided into six groups: normal, model, two positive controls, and two GPS tre...