Proteinases are enzymes that catalyse the breakdown of proteins. Proteinases are involved in many biological functions, including the digestion of ingested proteins, the breakdown of old proteins, and cell signalling.

PF-1355 is a selective 2-thiouracil mechanism-based MPO inhibitor. PF-1355 is used for treatment of vasculitic diseases.

Pueroside B may can treat coronary heart disease, it can interact with two or more targets[peroxisome proliferator activated receptor γ (PPAR-γ), angiotensin-converting enzyme (ACE), hydroxymethylglutaryl coenzyme A receptor (HMGR), cyclooxygenase-2 (COX2), and thrombin].