Papain is a proteolytic (protein-cleaving) enzyme derived from papaya. As an enzyme, it helps to catalyze (speed up) chemical reactions within the cell.

Papain aids in protein digestion and has a mild, soothing effect on the stomach. It is most often used as a meat tenderizer.

References

Kaul P, Sathish HA, Prakash V.Effect of metal ions on structure and activity of papain from Carica papaya.Nahrung. 2002 Feb;46(1):2-6.Leipner J, Saller R. Systemic enzyme therapy in oncology: effect and mode of action. Drugs 2000 Apr;59(4):769-80