NUKLEONIKA 2013, 58(2):255-259

 


DEUTERIUM ISOTOPE EFFECTS IN OXIDATION OF DOPAMINE
BY TYRAMINE OXIDASE



Małgorzata Pająk, Wioleta Byszewska, Marianna Kańska

Department of Chemistry, University of Warsaw,
1 L. Pasteur Str., 02-093 Warsaw, Poland



We report the studies on the mechanism of oxidation of dopamine (DA) to 3’,4’-dihydroxyphenylacetaldehyde (DOPAL) by enzyme tyramine oxidase (EC 1.4.3.6) using kinetic isotope effects (KIE) and solvent isotope effects (SIE) methods. For kinetic studies, the selectively deuterium labelled isotopologues of dopamine, i.e., [(1R)-2H]-, and [(1S)-2H]-DA were used. The numerical values of KIE’s for the (1R)- and (1S)-isotopologues of dopamine in the enzymatic oxidation of DA to DOPAL were determined using the non competitive spectrophotometric method. Also, the SIE’s for this reaction carried out in heavy water were obtained spectrophotometrically. Some mechanistic details of enzymatic oxidation of DA to DOPAL were discussed.


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