Cyclase

A cyclase is an enzyme, almost always a lyase, that catalyzes a chemical reaction to form a cyclic compound. Important cyclase enzymes include:
 * Adenylyl cyclase, which forms cyclic AMP from adenosine triphosphate
 * Guanylyl cyclase, which forms cyclic GMP from guanosine triphosphate
 * Guanylyl cyclase c