The aerobic oxidation of sulfite thus provides a magnified manometric response to the chain initiating event. Advantage was taken of this circumstance to develop an ultrasensitive assay for milk xanthine oxidase (5). The data obtained were consistent with the hypothesis that xanthine oxidase, when acting on purine substrates, initiates the aerobic oxidation of sulfite by the generation of free ...

The enhancement of CO2 fixation in isolated, intact spinach chloroplasts by ascorbate or by low sulfite concentrations (less than 1 mM) is strongly reduced or even abolished by the addition of superoxide dismutase (SOD). By the use of 35SO3(2-) it is demonstrated that the rate of sulfate formation is much lower than the sulfite induced increase in CO2 fixation. This indicates that the superoxid...

Two fluorescent probes, m-PSP and p-PSP , for sulfite and/or sulfide were constructed by connecting a pyridinium ion to a coumarin fluorophore through an α,β-unsaturated ketone. The presence of the pyridinium salt promoted the nucleophilic addition of sulfite and sulfide to the α,β-unsaturated ketone, which could be visualized by dramatic changes in the solution's color and fluorescence intensi...

BACKGROUND Wine yeasts can produce undesirable sulfur compounds during alcoholic fermentation, such as SO2 and H2S, in variable amounts depending mostly on the yeast strain but also on the conditions. However, although sulfur metabolism has been widely studied, some of the genetic determinants of differences in sulfite and/or sulfide production between wine yeast strains remain to be identified...

BACKGROUND Recent advances in the development of enzyme cocktails for degradation of lignocellulosic biomass, especially the discovery of lytic polysaccharide monooxygenases (LPMOs), have opened new perspectives for process design and optimization. Softwood biomass is an abundant resource in many parts of the world, including Scandinavia, but efficient pretreatment and subsequent enzymatic hydr...

The aerobic oxidation of sulfite thus provides a magnified manometric response to the chain initiating event. Advantage was taken of this circumstance to develop an ultrasensitive assay for milk xanthine oxidase (5). The data obtained were consistent with the hypothesis that xanthine oxidase, when acting on purine substrates, initiates the aerobic oxidation of sulfite by the generation of free ...

The molybdenum-containing enzyme sulfite oxidase catalyzes the conversion of sulfite to sulfate, the terminal step in the oxidative degradation of cysteine and methionine. Deficiency of this enzyme in humans usually leads to major neurological abnormalities and early death. The crystal structure of chicken liver sulfite oxidase at 1.9 A resolution reveals that each monomer of the dimeric enzyme...

Extracts of representative bacterial strains from the various families of photosynthetic prokaryotes are demonstrated to possess significant levels of sulfite reductase [EC 1.8.99.1; hydrogen-sulfide: (acceptor)oxidoreductase] activity with reduced methyl viologen as electron donor, but not NADPH(2). The enzyme is localized primarily in the soluble fraction of the extracts, in contrast to adeny...

Valorization of biomass to create sustainable bio-synthetic routes to chemicals, plastics, monomers, waxes, fuel and energy is a central tenet of the move towards a circular bio-economy. An area of particular importance is the ability to valorize low value waste/by-products such as lignin. Degradation of lignin can release potential chemical building blocks that can be used as substrates for th...

Previous papers in this series have reported the hypoxanthinedependent oxidation of sulfite by cyanide-inhibited xanthine oxidase (1) and experiments which permitted postulation of the structure of the active site of this enzyme (2). In the present study, xanthine oxidase acting on its substrates has been found to initiate the aerobic oxidation of sulfite by free radical chains of great length ...