Disease relevance of Dopaminechrome

• Dopamine-derived dopaminochrome promotes H(2)O(2) release at mitochondrial complex I: stimulation by rotenone, control by Ca(2+), and relevance to Parkinson disease [1].
• The toxic effect of dopaminochrome on murine neuroblastoma cells cultured in vitro is demonstrated together with the inhibition of dopaminochrome melanization induced by acetylcholine in vitro [2].
• Toxicity of dopamine and dopaminochrome on cultured cells [3].

High impact information on Dopaminechrome

• Reversible inhibition of alpha-synuclein fibrillization by dopaminochrome-mediated conformational alterations [4].
• We show here that the o-quinone dopaminochrome (DACHR), a relatively stable DA oxidation product, promotes concentration (0.1-0.2 mum)- and respiration-dependent generation of H(2)O(2) at Complex I in brain mitochondria, with further stimulation by low concentrations of rotenone (5-30 nm) [1].
• The enzyme possesses high substrate specificity, acting on L-dopachrome (Km = 1 mM at pH 6.8) and on L-alpha-methyl-dopachrome, but not on D-dopachrome, L-dopachrome methyl ester, dopaminochrome and adrenochrome [5].
• While the isomerase showed no activity toward preformed dopaminechrome, it readily influenced the stability of dopaminechrome generated in situ by tyrosinase [6].
• Rate constants for the implied chemical steps at different pH and temperature values have been evaluated from the measurement of the lag period arising from the accumulation of dopaminochrome that took place when dopamine was oxidized at acid pH [7].

Anatomical context of Dopaminechrome

• We have previously reported the presence, in human midbrain, of an enzymatic activity which catalyzes the formation of dopaminochrome from dopamine (DA) and hydrogen peroxide [8].

Associations of Dopaminechrome with other chemical compounds

• The dopaminechrome isomerase separated in the gels catalyzes dopaminechrome to 5,6-dihydroxyindole which is oxidized further by tyrosinase to colored melanochrome [9].
• The RBF fraction is strongly buffered against oxidation by compounds such as glutathione and by bioreductive enzymes such as DT-diaphorase (EC 1.6.99.2) which can use as a substrate menadione or dopaminochrome [10].

Gene context of Dopaminechrome

• The pathway for dopamine oxidation to dopaminochrome by tyrosinase has been studied as a system of various chemical reactions coupled to an enzymatic reaction [7].

References