Need GTPase for positive control
klenchin at macc.wisc.edu
Tue Aug 22 14:31:21 EST 1995
>AFAIK transducin is different from other G proteins in
that it has
>no GTPase activity when unstimulated. So you have to
>the rods to get transducin activity (BTW a nice control).
That's correct... and incorrect. Transducin sticks to
bleached rhodopsin and stays there practically irreversibly
in the absence of GTP. So a lot of crap could be stripped
off membranes, allowing for >80% pure G(t) elution by GTP.
So, for the GTPase assay one can purify 100% bleached
membranes and start reaction by GTP addition.
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