The catalytic subunit of the CaM-sensitive adenylyl cyclase can be purified to near homogeneity by several different purification protocols, although the yields of homogeneous catalytic subunit are still very slow. The most reliable purification method for this enzyme is CaM-Sepharose affinity chromatography. WGA-Sepharose and forskolin-Sepharose affinity columns also afford some purification of the enzyme, with WGA-Sepharose columns being more reproducible and reliable than forskolin-Sepharose. The catalytic subunit purified by these methods has an Mr of 150,000 +/- 15,000 and is apparently a glycopeptide which interacts directly with CaM and adenosine. This catalytic subunit-Gs complex has been reconstituted in vitro with beta-adrenergic receptors and muscarinic receptors and Gi.