Vanadate-Stimulated Nadh Oxidation Requires Polymeric Vanadate, Phosphate and Superoxide

Patole, Milind S.; Gullapalli, Sharada; Ramasarma, T.

doi:10.3109/10715768809055144

Cited by 11 publications

(9 citation statements)

References 17 publications

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“…cat ventricles, human heart erythrocytes, mouse liver plasma membranes and rat liver microsomes was stimulated by vanadates, [6][7][8] Vanadates are capable of oxidizing NADH under non-enzymic conditions. Isopolydecavanadate in presence of phosphate buffer was found to be an effective oxidant of NADH compared to other forms of vanadates viz.…”

Section: Mechanismmentioning

confidence: 99%

“…1-3 Studies on the electron transfer reaction of NADH and its synthetic analogue were reported by several workers. [4][5][6][7][8][9][10] The mechanism of reaction of NADH largely depends on the nature of oxidants. When the oxidants are iminium ions of activated carbonyl compounds 11 and quinone, 12 there is a transfer of hydride ion from the 4th position of the dihydropyridine ring to the oxidizing agent in the rate limiting step (scheme 1).…”

Section: Nadhmentioning

confidence: 99%

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Studies on electron transfer reactions of Keggin-type mixed addenda heteropolytungstovanadophosphates with NADH

Sami

Rajasekaran

2009

J Chem Sci

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The coenzyme nicotinamide adenine dinucleotide (NADH) undergoes facile electron transfer reaction with vanadium (V) substituted Keggin-type heteropolyanions (HPA) [PV V W 11 O 40 ] 4-(PV 1 ) and [PV V 2 W 10 O 40 ] 5-(PV 2 ) in aqueous phosphate buffer of pH 6 at ambient temperature. Electrochemical and optical studies show that the stoichiometry of the reaction is 1 : 2 (NADH : HPA). EPR and optical studies show that HPA act as one electron acceptor and the products of electron transfer reactions are one electron reduced heteropoly blues (HPB), viz. [PV IV W 11 O 40 ] 5-and [PV IV V V W 10 O 40 ] 6-.Oxygraph measurements show that there is no uptake of molecular oxygen during the course of reaction. The reaction proceeds through multi-step electron-proton-electron transfer mechanism, with rate limiting initial one electron transfer from NADH to HPA by outer sphere electron transfer process. Bimolecular rate constant for electron transfer reaction between NADH and PV 2 in phosphate buffer of pH = 6 has been determined spectrophotometrically.

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Section: Mechanismmentioning

confidence: 99%

Section: Nadhmentioning

confidence: 99%

Studies on electron transfer reactions of Keggin-type mixed addenda heteropolytungstovanadophosphates with NADH

Sami

Rajasekaran

2009

J Chem Sci

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“…The effect of varying [NADH] on the reaction rate was studied at fixed pH (7.5) and between 20-35 o C. The concentration of Co III W 5was kept constant and 10 4 [NADH] was changed from 5.07 to 15.22 mol dm -3 .…”

Section: Effect Of [Nadh] On Reaction Ratementioning

confidence: 99%

“…The reaction is reversible 8 , this means the coenzyme can continuously cycle between NAD + and NADH forms. Studies on the electron transfer reactions of NADH and its synthetic analogues have been reported [2][3][4][5][6][7][8] . Reduction of methemoglobin 9 , orthovanadate and vanadyl sulphate 10 , ferric siderophores 11 and heteropolytungstovanadophosphates 12 by NADH has been reported.…”

Section: Introductionmentioning

confidence: 99%

Nonenzymatic NADH‐Dependent Reduction of Keggin‐Type 12‐Tungstocobaltate(III) in Aqueous Medium

Kumari

Das

Baral

et al. 2010

Journal of Chemistry

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The kinetics of the electron transfer reaction of NADH with 12-tungstocobaltate(III) has been studied over the range 5.07 ≤ 104[NADH] ≤ 15.22 mol dm-3, 7.0 ≤ pH ≤ 8.0 and 20 ≤ t ≤ 35oC in aqueous medium. The electron transfer reaction showed first-order dependence each in [NADH]Tand [12-tungstocobaltate(III)]T. The products of the reaction were found to be NAD+and 12-tungstocobaltate(II). The activation parameters ΔH#(kJ mol-1) and ΔS#(JK-1mol-1) of the electron transfer reactions were found to be 64.4±1.8 and -48.86±6.0. Negative value of ΔS#is an indicative of an ordered transition state for the electron transfer reaction.

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“…Decavanadate was also reported to be more prone to reduction than metavanadate (monomer, dimer, tetramer, etc. ), and its cage-like structure remained unchanged after its partial reduction. − However, the structure–redox property relationship, underlying electron-transfer mechanism, and the properties of reduction products remained largely unknown for aquatic vanadium(V) species. In addition, the complexation of organic and inorganic ligands with vanadium(V) affects its redox behavior. , In particular, vanadium(V) forms stronger complexes with phosphate than other inorganic ligands .…”

Section: Introductionmentioning

confidence: 99%

Understanding the Reduction Kinetics of Aqueous Vanadium(V) and Transformation Products Using Rotating Ring-Disk Electrodes

Chen

Liu

2017

Environ. Sci. Technol.

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Vanadium(V) is an emerging contaminant in the most recent Environmental Protection Agency's candidate contaminant list (CCL4). The redox chemistry of vanadium controls its occurrence in the aquatic environment, but the impact of vanadium(V) speciation on the redox properties remains largely unknown. This study utilized the rotating ring-disk electrode technique to examine the reduction kinetics of four pH- and concentration-dependent vanadium(V) species in the presence and the absence of phosphate. Results showed that the reduction of VO, HVO (V), and HVO proceeded via a one-electron transfer, while that of NaHVO (V) underwent a two-electron transfer. Koutecky-Levich and Tafel analyses showed that the intrinsic reduction rate constants followed the order of V > VO > V > HVO. Ring-electrode collection efficiency indicated that the reduction product of V was stable, while those of VO, HVO, and V had short half-lives that ranged from milliseconds to seconds. With molar ratios of phosphate to vanadium(V) varying from 0 to 1, phosphate accelerated the reduction kinetics of V and V and enhanced the stability of the reduction products of VO, V, and HVO. This study suggests that phosphate complexation could enhance the reductive removal of vanadium(V) and inhibit the reoxidation of its reduction product in water treatment.

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Vanadate-Stimulated Nadh Oxidation Requires Polymeric Vanadate, Phosphate and Superoxide

Cited by 11 publications

References 17 publications

Studies on electron transfer reactions of Keggin-type mixed addenda heteropolytungstovanadophosphates with NADH

Studies on electron transfer reactions of Keggin-type mixed addenda heteropolytungstovanadophosphates with NADH

Nonenzymatic NADH‐Dependent Reduction of Keggin‐Type 12‐Tungstocobaltate(III) in Aqueous Medium

Understanding the Reduction Kinetics of Aqueous Vanadium(V) and Transformation Products Using Rotating Ring-Disk Electrodes

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