The reduction of methylene blue by sulfide ion in the absence and presence of oxygen: Simulation of the methylene blue-O2−HS−-CSTR oscillations

Resch, Peter; Schneider, F. W.; Field, Richard J.; Burger, Mária

doi:10.1007/bf02065355

Cited by 3 publications

(3 citation statements)

References 11 publications

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“…Upon injecting ≈ 10‐fold excess of NADH or (NAD) 2 into 5 × 10 −6 m methylene blue, the aerated solution ([O 2 ] = 0.252 m m ) temporarily loses its blue color. Although the reaction mechanism may be quite complex [33], the observed reactions can be summarized by , (1b) and .…”

Section: Resultsmentioning

confidence: 99%

Nicotinamide adenine dinucleotide species in the horseradish peroxidase–oxidase oscillator

Kirkor

Scheeline

2000

European Journal of Biochemistry

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NADH chemistry ancillary to the oscillatory peroxidase±oxidase (PO) reaction has been reexamined. Previously, (NAD) 2 has been thought of as a terminal, inert product of the PO reaction. We now show that (NAD) 2 is a central reactant in this system. Although we found traces of the dimer after several hours of the PO reaction, no accumulation of the dimer occurred, regardless of the reaction time or the number of oscillations. (NAD Keywords: horseradish peroxidase catalysis; methylene blue; NAD anomers; NAD dimer; rate constants.Peroxidases are widely distributed floral, fungal and animal heme-containing enzymes. Across the phyla, this class of enzymes participates in oxidations and reductions essential in anti-infectious defenses, hormonal signaling, and in a plants' formation and maintenance of cell walls. In mammals, peroxidases are also implicated in the pathology of inflammation. Horseradish peroxidase has found wide-spread use in a multitude of analytical assays and biosensors [1]. Due to its wide-range of catalytic activity and ready availability, HRP serves as the archetypal peroxidase in investigations of mechanisms of biochemical redox reactions. Even more importantly, pyridine nucleotides are the most common coenzymes in plant and animal cellular metabolism. NADH (Fig. 1) is one of a few substrates that activates both oxidase and peroxidase cycles of peroxidases. In stimulated neutrophils, pyridine coenzymes serve as the source of electrons shuttled by NADH oxidase through the plasma membrane to oxygen, in formation of superoxide radicals and activation of antimicrobial defenses, the chlorinating system of myeloperoxidase among them. The main target of this work is an assessment of the role of (NAD) 2 (Fig. 1) in reaction pathways operating in the horseradish peroxidase-catalyzed oxidation of NADH. A secondary goal concerns establishing the roles of other b-NADH-derived species in the PO reaction. Explorations of reduced nicotinamide adenine dinucleotide (NADH) reaction pathways are notoriously difficult. The difficulty lies in the wide range of transformations and instability of intermediates that can form. It is manifest in a large number of model compounds synthesized to restrict possible transformations. We select the HRP-NADH-O 2 oscillator as, on one hand, a more stringent framework for mechanistic evaluation of the relevant chemistry of NADH, and on the other hand, a medium kinetically enforcing a hierarchy of reaction pathways [2]. The HRP-NADH-O 2 reaction is the most thoroughly studied in the group of peroxidase oscillators [3]. The abstract models of this oscillator emulate its observable PO dynamics with general fidelity. Chemically realistic models, however, have been found lacking in simulating several features of the oscillator [4]. Our current work increases the number of reactions demonstrated to occur in the PO oscillator.In aqueous solutions of moderate acidity, the main transformations of nicotinamide adenine dinucleotide are acidcatalyzed autooxidation, anomerization, and hydration...

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Section: Resultsmentioning

confidence: 99%

Nicotinamide adenine dinucleotide species in the horseradish peroxidase–oxidase oscillator

Kirkor

Scheeline

2000

European Journal of Biochemistry

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“…65122) is found to remain pure for several months in a vacuum desiccator [29,45]. Methylene blue also catalyzes H 2 S autoxidation and the mechanism involves H 2 O 2 as an intermediate (see 4.3 ) [150,151]. This might at least in part explain the unreliability of the methylene blue method for the measurement of H 2 S concentration [29,45,152].…”

Section: H2s Reaction With Oxidantsmentioning

confidence: 99%

“…It is an interesting reaction because the pH of the reaction mixture oscillates between acid and base as the reaction proceeds [162,163]. Although the reaction mechanism is still not clear [151,156,161,164–167], the reported rate constants are similar (Table 1) [151,154,156]. Among these studies, Hoffmann’s work [156] deserves to be mentioned because the reaction solution was buffered, metal chelator was added (to avoid the catalytic effect of ferric iron), and the mechanism was examined [167].…”

Section: H2s Reaction With Oxidantsmentioning

confidence: 99%

Chemical foundations of hydrogen sulfide biology

2013

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Following nitric oxide (nitrogen monoxide) and carbon monoxide, hydrogen sulfide (or its newer systematic name sulfane, H2S) became the third small molecule that can be both toxic and beneficial depending on the concentration. In spite of its impressive therapeutic potential, the underlying mechanisms for its beneficial effects remain unclear. Any novel mechanism has to obey fundamental chemical principles. H2S chemistry was studied long before its biological relevance was discovered, however, with a few exceptions, these past works have received relatively little attention in the path of exploring the mechanistic conundrum of H2S biological functions. This review calls attention to the basic physical and chemical properties of H2S, focuses on the chemistry between H2S and its three potential biological targets: oxidants, metals and thiol derivatives, discusses the applications of these basics into H2S biology and methodology, and introduces the standard terminology to this youthful field.

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Pico-level DNA sensing by hetero-polymetalate, Na10{Dy2W10O30(µ-S)6}·80H2O, cluster

2018

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The reduction of methylene blue by sulfide ion in the absence and presence of oxygen: Simulation of the methylene blue-O2−HS−-CSTR oscillations

Cited by 3 publications

References 11 publications

Nicotinamide adenine dinucleotide species in the horseradish peroxidase–oxidase oscillator

Nicotinamide adenine dinucleotide species in the horseradish peroxidase–oxidase oscillator

Chemical foundations of hydrogen sulfide biology

Pico-level DNA sensing by hetero-polymetalate, Na10{Dy2W10O30(µ-S)6}·80H2O, cluster

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