You may be interested to read the following paper published recently. This
is in continuation of our efforts to show that kinetin is a naturally
occurring cytokinin, which may have important role to play as an
antioxidative defense molcule:
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from: FEBS Letters, vol 393; pp. 197-200, 1997. (September 16 issue)
A mechanism for the in vivo formation of N6-furfuryladenine, kinetin, as a
secondary oxidative damage product of DNA
Jan Barciszewski, Gunhild E. Siboska, Bent O. Pedersen, Brian F.C. Clark,
and Suresh I.S. Rattan
Laboratory of Cellular Ageing, Department of Molecular and Structural
Biology, bDepartment of Chemistry, University of Aarhus, DK-8000 Aarhus -
C, Denmark Institute of Bioorganic Chemistry, Polish Academy of Sciences,
Noskowskiego 12, 61704 Poznan, Poland.
Abstract
Recently, we have reported the presence of kinetin (N6-furfuryladenine) in
commercially available DNA, in freshly extracted cellular DNA and in plant
cell extracts. We have also found that kinetin has electrochemical
properties which can be used for monitoring the level of this modified base
in DNA. Here, for the first time, we propose a mechanism for the formation
of kinetin in DNA in vivo, based on the analyses of its mass spectra. Since
hydroxy radical oxidation at the carbon 5' of the deoxyribose residue
yields furfural, we propose that this aldehyde reacts with the amino group
of adenine and, after intramolecular rearrangement, kinetin is formed in
vivo. Thus kinetin is the first stable secondary DNA damage product known
to date with very well defined cytokinin and anti-aging properties, linked
to oxidative processes in the cell. These results also indicate that
N6-furfuryladenine or kinetin is an important component of a new salvage
pathway of hydroxy radicals constituting a "free radical sink". In this
way, the cells can neutralize the harmful properties of hydroxyl radical
reaction products, such as furfural, and respond to oxidative stress by
inducing defence mechanisms of maintenance and repair.
Key words: Kinetin, 6-furfuryladenine, Oxidation, DNA damage, Base propenals
Dr. Suresh I. S. Rattan, PhD; DSc
Laboratory of Cellular Ageing
IMSB
University of Aarhus
Forskerparken
DK-8000 Aarhus - C
Denmark
Tlf: +45 89 42 50 34 Fax: +45 86 20 12 22
