Aha!  It's been so long I hadn't thought of that.

The original binding assay used a specific cAMP-binding protein from mammals (PKA regulatory subunit from beef heart), and measured competition between a cold sample and a tritiated standard.  One of the really nice features of this assay was that the PKA-R had essentially zero affinity for deoxycyclicAMP, whereas the Dictyostelium receptors responded well to it.  Thus you could stimulate the Dicty and only measure what they made.  The antibody is apparently not so selective.

As far as I know, you can't get the original sort of kit, but you could make it if you want to (fairly straightforwardly - I have done so myself - Sigma no longer sell PKA, but Merck do, cat. 539577).

	Robert


On 29 Sep 2011, at 12:23, Terri Bruce wrote:

> We've tried the ELISA in the Temesvari lab at Clemson. The problem is that if you use a cAMP analog during your experiment, the ELISA picks it up as well. It saturates your ELISA and you can't get a measure of your cAMP production over the analog background. (Not to mention, as Dr. Insall said, they are expensive.)
> 
> Has anyone gotten the ELISA to work?  If so, I would be interested in your protocol!

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Professor Robert Insall
CR-UK Beatson Institute for Cancer Research
Switchback Road, Bearsden
Glasgow G61 1BD, UK

Tel.  (0/44) 141 330 4005
Web http://www.beatson.gla.ac.uk/robert_insall
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