Linked Life Data

15134917

Source:http://linkedlifedata.com/resource/pubmed/id/15134917

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2004-5-11
pubmed:abstractText
The effect of transition metal ions on the electrochemistry of 6-methoxy-5,8-quinolinedione (L1), 7-amino-6-methoxy-5,8-quinolinedione (L2) and the antitumor antibiotic streptonigrin (SN) was studied. In 10% methanol/water, the one-electron reduction of quinones L1 and L2 to the corresponding semiquinones is shifted to more positive potentials upon addition of one equivalent of Zn(II), Ni(II), Co(II) or Cd(II) and is consistent with formation of a 1:1 complex involving the quinone(N) and adjacent quinone(O). Similar results are observed for Cu(II) and Mn(II), but the redox chemistry is also complicated by metal-based redox chemistry. The addition of further equivalents of M(II) results in a number of different coordination and electrochemical processes including formation of 1:1 and 2:1 complexes of the quinone, semiquinone and dianion. Under similar conditions, the 1:1 SN 2,2'-bipyridyl metal complex undergoes a reversible one-electron reduction to the semiquinone. The redox potential of the quinone in SN was shifted positive in the presence of the metal ions, but both the magnitude of the shift, and the relative influence of the metals was different to ligands L1 and L2. The changes in redox chemistry of SN compared with L1 and L2 are consistent with the formation of the 2,2-bipyridyl complexes in which there is weaker coordination to the quinone(O) in ring A of SN. These results suggest that in vivo, metal ions such as Zn(II), Cu(II) and Mn(II) facilitate the initial reduction of streptonigrin to the semiquinone by capturing the semiquinone after SN is reduced by biological reductants.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0162-0134
pubmed:author
pubmed:issnType
Print
pubmed:volume
98
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
720-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
The effect of metal ions on the electrochemistry of the antitumor antibiotic streptonigrin.
pubmed:affiliation
School of Chemistry, The University of Sydney, Building F11, Sydney, NSW 2006, Australia.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't