Abstract
Activation of the purified guanine nucleotide-binding regulatory component (G/F) of [rabbit liver] adenylate cyclase by F- requires the presence of Mg2+ and another factor. This factor, which contaminates commercial preparations of various nucleotides and disposable glass test tubes, was identified as Al3+. In the presence of 10 mM Mg2+ and 5 mM F-, AlCl3 causes activation of G/F with an apparent activation constant of .apprx. 1-5 .mu.M. The requirement for Al3+ is highly specific; of 28 other metals tested, only Be2+ promoted activation of G/F by F-.