87-kDa PARP activity

Araluen Freeman araluen_f at nospam.geocities.com
Tue Oct 2 10:52:20 EST 2001

Hi all,

I've been getting some weird results with Western and activity blots of
poly(ADP-ribose) polymerase (PARP).  I was wondering if someone else has
worked with PARP also, and might share some of their observations of the

Simply put, we're detecting the full PARP-1 enzyme at ~120-kDa with the
C2-10 anti-PARP antibody, as well as the 87-kDa cleavage product (AND a
100-kDa band, but that's another story).  However, in the corresponding
activity blot, we aren't getting one hint of activity from the full enzyme,
instead picking up distinct basal activity from the 87-kDa cleavage product.

What we're baffled by is the lack of activity from the full enzyme.  There's
a few ideas flying around (there always are), but I thought I'd test the
waters to see if there is anyone else that might have had their paws on one
of the PARPs and have an idea.  One suggestion has been that perhaps the
~120-kDa PARP-1 we're detecting is already modified, preventing the in vitro
activity, but reports have shown that significant self-modification leads to
slower electrophoretic mobilities -- our Western is giving us the same tidy
band at ~120-kDa.

Anyways, thanking anyone for their suggestions!  ;-)

 Araluen.

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