Journal article
Ascorbate both activates and inactivates bleomycin by free radical generation
Biochemistry (Easton), Vol.31(40), pp.9784-9788
10/01/1992
DOI: 10.1021/bi00155a035
PMID: 1382593
Abstract
The chemotherapeutic agent bleomycin (BLM) is activated by reducing agents to break isolated DNA. Paradoxically, these same reducing agents protect cellular DNA from BLM damage. To resolve this paradox, we have examined the reaction of FemBLM with DNA in the presence of ascorbate. As expected, ascorbate augments FemBLM-induced DNA damage. However, when ascorbate is added to FemBLM prior to exposure to DNA, a redox-inactive BLM is produced in a reaction that generates the ascorbyl radical. This reaction occurs in both ascorbate-supplemented buffer and unsupplemented plasma. In buffered solution, this reaction was found to be stoichiometric; for each mole of BLM present, 6.9 mol of ascorbate was oxidized and 4.7 mol of oxygen was consumed. Iron was found to serve only as a catalyst for the reaction. These data suggest that both activation of BLM and the generation of redox-inactive BLM occur via the same reaction and that BLM-induced DNA damage depends upon BLM reaching DNA prior to its interaction with reducing agents
Details
- Title: Subtitle
- Ascorbate both activates and inactivates bleomycin by free radical generation
- Creators
- Garry R BuettnerPope L Moseley
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.31(40), pp.9784-9788
- Publisher
- American Chemical Society
- DOI
- 10.1021/bi00155a035
- PMID
- 1382593
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Language
- English
- Date published
- 10/01/1992
- Academic Unit
- Radiation Oncology
- Record Identifier
- 9984047856402771
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