© 1994 Oxford University Press
research-article |
Free radical-induced fragmentation of proteins by quercetin
Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University Aligarh202002 (UP)India
1Department of Biochemistry andMolecular Biology, The University of Leeds Leeds LS2 9JT, UK
2To whom correspondence should be addressed
The flavonoid, quercetin, is known to bind to DNA and, in the presence of Cu(II) and other ions, causes fragmentation of the molecule. We examined whether quercetin might bind to protein and cause similar fragmentation. By using UV spectroscopic and fluorescence quenching experiments we show that quercetin binds to bovine serum albumin and that the complex does, in the presence of Cu(II), lead to fragmentation of the protein. The binding involves binding to tryptophan residues in the albumin. The reaction is not detected in certain other tryptophan-containing proteins. We discuss the possible implications for protein damage by this and other radical-generating reagents.