What is "actinidain"

n. (alternative form of actinidin English)

Actinidain (, actinidin, Actinidia anionic protease, proteinase A2 of Actinidia chinensis) is a type of cysteine protease enzyme found in fruits including kiwifruit (genus Actinidia), pineapple, mango, banana and papaya. This enzyme is part of the papain-like peptidase C1 family. This enzyme catalyses the following chemical reaction similar to that of papain.

From the kiwi fruit or Chinese gooseberry ( Actinidia chinensis).

It is a known allergen and commercially useful as a meat tenderizer.