Related Experiment Videos
Oxidation of mitoxantrone by lactoperoxidase
Thomas B Brück1, Patricia J Harvey
1School of Chemical and Life Sciences, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK.
Biochimica Et Biophysica Acta
|July 25, 2003
Summary
The lactoperoxidase enzyme activates the anti-cancer drug mitoxantrone. Nitrite modulates this process, influencing drug metabolism and potentially its efficacy.
Area of Science:
- Biochemistry
- Enzymology
- Pharmacology
Background:
- Mitoxantrone is an anthraquinone anti-cancer drug.
- The lactoperoxidase (LPO) system is involved in biological oxidation processes.
Purpose of the Study:
- To investigate the spectrophotometric study of LPO-catalyzed mitoxantrone oxidation.
- To elucidate the reaction mechanism and kinetics of mitoxantrone oxidation by LPO intermediates.
Main Methods:
- Spectrophotometry
- Stopped-flow apparatus
- Enzyme kinetics analysis
Main Results:
- Mitoxantrone forms deactivating complexes with LPO Compound I and Compound II.
- Rate constants for mitoxantrone reduction by Compound I and II were determined.
- Compound II is the steady-state intermediate, but can form an inactive Compound III with H2O2.
- Nitrite inhibits Compound III formation and increases oxidized mitoxantrone metabolites (MH2(2+) and MH).
Conclusions:
- LPO catalyzes mitoxantrone oxidation through defined intermediates.
- Nitrite plays a crucial role in modulating the LPO-mediated oxidation pathway of mitoxantrone.
- Understanding these interactions is vital for the biological implications of drug activation.