An artifact produced by boiling adenyl cyclase reaction mixtures prior to the cyclic AMP-radioimmunoassay.

An artifact of procedure has been detected in the adaptation of the cAMP-radioimmunoassay to the analysis of adenyl cyclase activity. When reaction mixtures containing ATP and MgCl2 were boiled to terminate the enzyme assay, a cAMP-like decrease in antigen-binding was found. This decrease was dependent upon the presence of ATP, was linear to at least 5 min of boiling time, and could be destroyed with the addition of commercial phosphodiesterase. As significant levels of the nonenzymatically formed product resulted only when samples were boiled, alternative methods of terminating cyclase reactions are suggested.