Capillary and Pulsed Field Gel Electrophoresis

As an example for the study of DNA damage after irradiation using this technique may serve reference (Valenzuela et al. 2000). 

The 32P-postlabeling technique allows to improve the sensitivity of the detection of DNA damage (Cadet et al. 1998). The damaged DNA is enzymatically degraded into nucleotide-3-phosphates [reaction (7)]. The resulting mixture of unchanged nucleoside-3-phosphates (dNp) and damaged ones (dXP) are separated by HPLC [reaction (8)]. They are then labeled at the 5 -position with 32P [reaction (9)] and subsequently dephosphorylated at the 3 -position [reaction (10)]. This allows to proceed with a second purification and their identification by, for example, two-dimensional TLC [reactions (11) and (12)]. 

Factors that affect the determination of 8-oxo-G by this technique have been discussed in some detail (Moller et al. 1998). The determination of Tg by this technique (Hegi et al. 1989) is one of its most sensitive assays (Weinfeld and Soderlind 1991), many orders of magnitude higher than the earlier determination by HPLC (Frenkel et al. 1981). A 32P-postlabeling assay for the cA lesion which blocks gene 

2000) has also been developed for the use in mammalian tissues (Randerath et al. 

Ade-N-l-oxide, a product that is formed when DNA is exposed to H2O2, has also been determined using this technique (Mouret et al. 1990). 

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