nature of "radiolysis" of probes

Pamela Norton pamela.norton at mail.tju.edu
Fri Jan 18 13:23:49 EST 2002


In article <v04011701b86b7019465c@[144.92.64.179]>, Michael L. Sullivan
<mlsulliv at facstaff.wisc.edu> wrote:

> I have a question on the nature of "radiolyis" of P-32 hybridiazation
> probes.  When people talk about probes breaking down due to radiolysis, is
> that occuring because of
> 
> 1) decay of the incorporated P-32 to S-32 results in breakage of the
> phosphodiester bond in some way
> 
> 2) the action of the emitted beta particals in the sample results in
> fragmentation of the probe
> 
> 3) a combination of the above two processes.
> 
> I'm mostly curious (but also have a more practical matter in mind about a
> failed hybridization) and haven't really found the answer anywhere else.
> 
> Thanks,
> 
> Mike
> 
> ---

I believe that #3 is correct. This belief is based on part on observing
that 32P-labelled rNTPs and dNTP stocks become unusable much faster
than would be accounted for by the isotope decay rate. That is, stocks
greater than one half life old perform very poorly. On the other hand,
33P-labelled dNTPs remain usable for months in sequencing reactions. I
suspect that the emitted 32P beta particles are damaging the
nucleotides. 

Any information besides this admittedly anecdotal account is welcome.

Pam Norton




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