879. The mechanism of the reduction of adrenochrome by ascorbic acid

Mattok, G. L.

doi:10.1039/jr9650004728

Cited by 15 publications

(3 citation statements)

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“…This again would seem to be compared with that of VO(LH)+ and that the kineticdata are reasonable as the nitrogen proton could well facilitate electron only accurate enough to detect the term in the denominator in transfer by interaction with the vanadyl oxygen atom (the sideequation (31) that depends on [H'],, then to a fair chain of adrenaline is certainly long enough) thus making approximation the [O,]-dependent term becomes that shown by (32). This exactly parallels the first term in the experimental rate equation (5) and thus the experimental values of A, B, C, and D can be used to calculate the equilibrium constants appearing in the term (32); log CPYPv,,L,,/Pvo(LH~J = reaction (8) more favourable than reaction (9). A study of the anaerobic oxidation of adrenaline by vanadyl ions is at present being undertaken and this should enable values of k , and k, to be obtained independently.…”

Section: Dependence Of Kob On [Vo]t and [Lit-a Series Of Runs Wassupporting

confidence: 76%

The oxovanadyl(IV) catalysed oxidation of adrenaline by molecular oxygen

Jameson¹,

Kiss²

1986

J. Chem. Soc., Dalton Trans.

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Section: Dependence Of Kob On [Vo]t and [Lit-a Series Of Runs Wassupporting

confidence: 76%

The oxovanadyl(IV) catalysed oxidation of adrenaline by molecular oxygen

Jameson¹,

Kiss²

1986

J. Chem. Soc., Dalton Trans.

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“…The kinetics of ascorbate oxidation by PAESeO were determined from a spectrophotometric assay of ascorbate depletion at 300 nm (Skotland & Ljones, 1980;Mattok, 1965). Ascorbate solutions were prepared in deoxygenated 0.127 M NaOAc buffer, pH 5.0, and the extinction coefficient at 300 nm was determined for each solution prior to its use.…”

Section: Methodsmentioning

confidence: 99%

Ascorbate depletion as a consequence of product recycling during dopamine .beta.-monooxygenase catalyzed selenoxidation

May¹,

Herman²,

Roberts³

et al. 1987

Biochemistry

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The competence of dopamine beta-monooxygenase (DBM) to process selenide substrates was investigated, in anticipation that the expected selenoxide products would exhibit unique reactivity and redox properties. The prototypical selenide phenyl 2-aminoethyl selenide (PAESe) was synthesized and shown to be a substrate for DBM with the characteristic e/O2 ratio of 2:1 for monooxygenation. The kinetic parameters for oxygenation of PAESe were found to be similar to those for the DBM-catalyzed sulfoxidation of the cognate sulfide phenyl 2-aminoethyl sulfide [May, S. W., & Phillips, R. S. (1980) J. Am. Chem. Soc. 102, 5981-5983], and selenoxidation was stimulated by fumarate in a manner similar to other well-characterized DBM monooxygenation reactions. Identification of phenyl 2-aminoethyl selenoxide (PAESeO) as the enzymatic product was accomplished by the demonstration of coincident elution of authentic PAESeO with the enzymatic product in three significantly different HPLC systems. PAESeO was found to oxidize ascorbic acid with the concomitant and stoichiometric reduction of PAESeO back to the selenide, PAESe. As a consequence of this nonenzymatic reaction, ascorbate-supported DBM turnover was prematurely terminated under standard assay conditions due to depletion of reduced ascorbate. The kinetics of the redox reaction between PAESeO and ascorbate were investigated with a spectrophotometric assay of ascorbate at 300 nm, and a second-order rate constant of 3.4 M-1 s-1 was determined at pH 5.0, 25 degrees C. Spectrophotometric assay of cytochrome c (cyt c) reduction at 550 nm during the oxidation of ascorbate by PAESeO demonstrated that no cyt c trappable semidehydroascorbate was produced in this nonenzymatic reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Aminochromes formed by the oxidation of catecholamines, in virtue of their indolinequinone ring, are also very prone to bind or oxidize various cellular nucleophiles, namely GSH, cysteine, and protein -SH groups [129,628,647,648]. They can impair the action of several enzymes or affect biological membranes [360,430,461].…”

Section: Toxicity Of Catecholamine Oxidation Productsmentioning

confidence: 98%

Contribution of Catecholamine Reactive Intermediates and Oxidative Stress to the Pathologic Features of Heart Diseases

Costa

Carvalho

Bastos

et al. 2011

CMC

100

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Pathologic heart conditions, particularly heart failure (HF) and ischemia-reperfusion (I/R) injury, are characterized by sustained elevation of plasma and interstitial catecholamine levels, as well as by the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Despite the continuous and extensive research on catecholamines since the early years of the XX(th) century, the mechanisms underlying catecholamine-induced cardiotoxicity are still not fully elucidated. The role of catecholamines in HF, stress cardiomyopathy, I/R injury, ageing, stress, and pheochromocytoma will be thoroughly discussed. Furthermore and although the noxious effects resulting from catecholamine excess have traditionally been linked to adrenoceptors, in fact, several evidences indicate that oxidative stress and the oxidation of catecholamines can have important roles in catecholamine-induced cardiotoxicity. Accordingly, the reactive intermediates formed during catecholamine oxidation have been associated with cardiac toxicity, both in in vitro and in vivo studies. An insight into the influence of ROS, RNS, and catecholamine oxidation products on several heart diseases and their clinical course will be provided. In addition, the source and type of oxidant species formed in some heart pathologies will be referred. In this review a special focus will be given to the research of cardiac pathologies where catecholamines and oxidative stress are involved. An integrated vision of these matters is required and will be provided along this review, namely how the concomitant surge of catecholamines and ROS occurs and how they can be interconnected. The concomitant presence of these factors can elicit peculiar and not fully characterized responses on the heart. We will approach the existing data with new perspectives as they can help explaining several controversial results regarding cardiovascular diseases and the redox ability of catecholamines.

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879. The mechanism of the reduction of adrenochrome by ascorbic acid

Cited by 15 publications

References 0 publications

The oxovanadyl(IV) catalysed oxidation of adrenaline by molecular oxygen

The oxovanadyl(IV) catalysed oxidation of adrenaline by molecular oxygen

Ascorbate depletion as a consequence of product recycling during dopamine .beta.-monooxygenase catalyzed selenoxidation

Contribution of Catecholamine Reactive Intermediates and Oxidative Stress to the Pathologic Features of Heart Diseases

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