noun. An endopeptidase, such as pepsin, trypsin, or papain.

noun. protease

noun. any enzyme that catalyzes the splitting of proteins into smaller peptide fractions and amino acids by a process known as proteolysis

"One of these roles involves activation of a class of cell surface proteins called proteinase activated receptors PARs."

enzyme  

ace  angiotensin converting enzyme  angiotensin-converting enzyme  caspase  plasminogen activator  

X-linked  adduct  carvone  cholinesterase  cyclooxygenase-2