In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: Rolipram is an inhibitor of the enzyme that degrades this compound. The asthma and COPD drug theophylline inhibits conversion of pulmonary fibroblasts into myofibroblasts by increasing the intracellular amount of this molecule. The slime moldDictyostelium excretes this molecule to signal aggregation into a sporocarp. This molecule was discovered as part of Earl Sutherland's investigation of the activity of epinephrine. In bacteria, the accumulation of this compound in a low glucose environment is responsible for the upregulation of the lac operon when this compound complexes with CRP. This molecule's inactivation is catalyzed by phosphodiesterase four, and it is produced along with a pyrophosphate in a reaction catalyzed by adenylyl cyclase. For 10 points, name this molecule which primarily activates protein kinase A, a second messenger which is synthesized from ATP.
A:
Science