Pulsed irradiation studies of some reactive intermediates of melanogenesis

Land, Edward J.

doi:10.1007/bf03155994

Cited by 20 publications

(2 citation statements)

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“…These results confirm that the interaction of DOPA with O z2 2 leads to the production of H 2 O 2 according to reaction (1). The dependence of H 2 O 2 formation on SOD concentration, in the assumption of competition between DOPA and SOD for superoxide, is described by the following equation:…”

Section: Studies Of the Reaction Of Dopa With Superoxidesupporting

confidence: 80%

“…It has been reported for a number of these compounds that their auto-and enzymatic oxidation leads to the formation of highly reactive ortho-semiquinone radicals, which can react with dissolved oxygen to give superoxide anion [1,2]. Among other catechols DOPA is involved in a number of important biological functions, demonstrating significant neurologic activity and being a key intermediate in the biosynthesis of melanin.…”

Section: Introductionmentioning

confidence: 99%

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Superoxide and hydrogen peroxide formation during enzymatic oxidation of DOPA by phenoloxidase

Komarov

Slepneva

Глупов

et al. 2005

Free Radical Research

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Generation of superoxide anion and hydrogen peroxide during enzymatic oxidation of 3-(3,4-dihydroxyphenyl)-DL-alanine (DOPA) has been studied. The ability of DOPA to react with O2*- has been revealed. EPR spectrum of DOPA-semiquinone formed upon oxidation of DOPA by O2*- was observed using spin stabilization technique of ortho-semiquinones by Zn2+ ions. Simultaneously, the oxidation of DOPA by O2*- was found to produce hydrogen peroxide (H2O2). The analysis of H2O2 formation upon oxidation of DOPA by O2*- using 1-hydroxy-3-carboxy-pyrrolidine (CP-H), and SOD as competitive reagents for superoxide provides consistent values of the rate constant for the reaction between DOPA and O2*- being equal to (3.4+/-0.6)x10(5) M(-1) s(-1). The formation of H2O2 during enzymatic oxidation of DOPA by phenoloxidase (PO) has been shown. The H2O2 production was found to be SOD-sensitive. The inhibition of H2O2 production by SOD was about 25% indicating that H2O2 is produced both from superoxide anion and via two-electron reduction of oxygen at the enzyme. The attempts to detect superoxide production during enzymatic oxidation of DOPA using a number of spin traps failed apparently due to high value of the rate constant for DOPA interaction with O2*-.

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Section: Studies Of the Reaction Of Dopa With Superoxidesupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%