When Is Adenylyl Cyclase Active?

Adenylyl cyclase activity is controlled by heterotrimeric G proteins. The inactive or inhibitory form exists when the complex consists of alpha, beta, and gamma subunits, with GDP bound to the alpha subunit. In order to become active, a ligand must bind to the receptor and cause a conformational change.

What is adenylyl cyclase activated by?

A soluble (non-membrane bound) form of adenylyl cyclase has recently been characterized in mammalian sperm. This form of the enzyme appears to be activated by bicarbonate ion.

When adenylyl cyclase is activated by the G protein what will be produced from ATP?

When activated, adenylyl cyclase converts a large number of ATP molecules into signaling molecules, called cyclic AMP (cAMP). Because cAMP carries the message of the first messenger (epinephrine) into the cell, cAMP is referred to as a second messenger.