papaina

Papaina, also known as papain, is a cysteine protease enzyme isolated from the latex of unripe papaya (Carica papaya). It catalyzes the hydrolysis of peptide bonds in proteins and is widely used for its proteolytic activity. Papaina is part of the C1 family of cysteine proteases and relies on a catalytic cysteine–histidine dyad for activity.

Source and production: Papaina is obtained from papaya latex by extraction and purification. It can also be produced recombinantly in microbial systems. Commercial preparations range from crude latex extracts to highly purified enzymes. The enzyme has optimum activity around neutral pH and moderate temperatures and is inactivated by heat and extreme pH. It is sensitive to oxidation and certain inhibitors.

Applications: In the food industry, papaina is used as a meat tenderizer, by breaking down proteins to soften muscle fibers and connective tissue. It is also used to clarify some fruit juices, wines, and beers. In medicine and nutrition, papaina is marketed as a digestive aid in some enzyme supplement products. In cosmetics, papaina is used in enzymatic exfoliants and some skin-care products to remove dead tissue.

Safety and regulation: Papaina can trigger allergic reactions in people with latex or papaya allergies. It can irritate skin and mucous membranes in concentrated forms. Regulatory status varies by country; labeling is important for allergen risk. It should be used according to product instructions to avoid overexposure.