Term: urease: an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia; is present in intestinal bacteria
Broader: activator: (biology) any agency bringing about activation; a molecule that increases the activity of an enzyme or a protein that increases the production of a gene product in DNA transcription | Unrelated: reticuloendothelial system: a widely distributed system consisting of all the cells able to ingest bacteria or colloidal particles etc, except for certain white blood cells