anti-phosphoserine/anti-phosphothreonine... any good?

Bernard P. Murray, PhD bpmurray*STUFFER* at
Thu Feb 25 16:26:35 EST 1999

In article <36D3F0BD.233B7750 at>, jp.nougayrede at wrote:

> Hello.
> Do you mean that anti-PY such as 4G10 or PY20 Mabs also recognise Pser and
> Pthr residues ?

I will have to check with my ex-colleagues to see which antibody
they were using.  I remember that they were not happy that
something was Ptyr unless the binding was preserved after
alkaline treatment and/or could be competed by free Ptyr.
They checked their findings by phosphopeptide mapping.
The immpression that I gained was that eg. anti-Ptyr
antibodies were *selective* rather than specific (and this
is a problem because of the low abundance of Ptyr).
The alkali treatment was a big help when looking at in vivo
labelling of cultured cells with 32P.

> Furthermore, do you have in mind any reference from your previous lab about
> the "differential lability to alkali" ?
> Thanks in advance.
> JP Nougayrede.

I just scanned MedLine and could find no specific reference to
this but several abstracts mention Ptyr analysis and testing
the specificity with hot KOH (you have to use PVDF membranes).
I have a vague recollection that the original reference is
fairly old (maybe mid 80's).  I need to find the reference
as I have mentioned it to my current lab-mates and now
they want to know the protocol.  If I find it I'll e-mail
you the reference.
     For the sake of completeness I should add that P-his
is also fairly alkaline stable (but is acid labile).

Bernard P. Murray, PhD
Dept. Cell. Mol. Pharmacol., UCSF, San Francisco, USA

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