Chemistry Reference
In-Depth Information
Table 10. 29.
Products and their
G
values (unit: 10
−
7
mol J
−
1
) from
γ
-irradiated solutions of
D
-ribose-5-phosphate. (Stelter et al. 1976)
Product
N
2
O
N
2
O/Fe(II)
N
2
O/Fe(III)
N
2
O/H
2
O
2
N
2
O/O
2
Inorganic phosphate
1.35
n.d.
n.d.
1.45
0.62
Pentodialdose
0.23
0.47
0.65
0.38
0.10
2-Hydroxy-4-oxoglutaral-
dehyde
0.07
Absent
Absent
0.07
Absent
5-Deoxypentos-4-ulose
0.10
0.83
0.44
0.1
Absent
3-Oxoglutaraldehyde
0.06
Absent
Absent
0.06
Absent
Tetrodialdose
Absent
Absent
Absent
Absent
0.42
Formic acid
Absent
Absent
Absent
Absent
0.43
Minor phosphate-free
products
0.1
Absent
0.12
0.06
0.09
n.d., Not determined
substantiate the view expressed above. They will not be discussed in more de-
tail.
In DNA, H-abstraction at
C
(4
) leads to strand breakage and the same prod-
ucts as repor ted here are formed in t he course of t his process (Chap. 12.4). In t his
reaction, an alkene radical cation/phosphate anion pair is formed. The dynam-
ics of this reaction has been studied in some detail with the help of adequately
substituted model systems (Crich and Huang 2001).
′
10.8.6
Oxidation at
C
(5
′
)
The formation of purine 5
′
,8-cyclonucleosides and -cyclonucleotides and py-
rimidine 5
).
Because it involves an addition of an alkyl radical to the base moiety, this re-
action has already been discussed in Section 5.3.1. The dAdo
C
(5
′
,6-cyclco-nucleosides are a typical product of an oxidation at
C
(5
′
) radical was
generated specifically by reacting 8BrdAdo with e
aq
−
. The ensuing reactions are
discussed in Section 7.2.
According to the study on Thd already mentioned above (Dizdaroglu et al.
1976), the release of Thy is connected with the formation of 2,4-dideoxypentodi-
aldose [reactions (262) and (263)].
′
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