Purification of bovine brain adenylyl cyclase with a novel derivative of forskolin: evidence for a high specific activity form of the enzyme.

Abstract An improved affinity support for the purification of adenylyl cyclase was prepared from 7-desacetyl-7-aminoethylaminocarbonyl forskolin. This analog allows convenient synthesis of an affinity matrix that is chemically stable, withstanding repeated use for up to two years, and efficient, yielding purifications of adenylyl cyclase from solubilized bovine brain membranes of 2,000–6,000 fold in a single step. Immunoblotting data suggest that the majority of the enzyme purified in this fashion differs from forms described previously. Since the specific activity of this preparation is substantially higher than that described in previous reports, it is possible that the purification described here selects, presumably on the basis of affinity for forskolin, for a form of adenylyl cyclase with higher specific activity than any described previously.