Wiktionary
n. (context enzyme English) An enzyme derived from figs.
Wikipedia
'' Ficain (, ficin, debricin, higueroxyl delabarre) is an enzyme that is derived from figs latex. It is of a family of proteases known as the cysteine endopeptidases, a group that also includes papain derived from papaya latex, bromelase ( bromelain) extracted from pineapple stem, calpain, caspases, cathepsin B, and chymopapain. It is one of the most commonly used for differentiating many blood group antigens: For example, it destroys M, N, S, Duffy a, and Duffy b, and enhances some other antigens including antigens from the Rh, Kidd, Lewis, I, and P1 systems.
It is a common occurrence when eating the skins or the white pulp directly inside the skin of a fig to get a burning or itching sensation. This is due to the ficin in the latex (sap) of the fruit, particularly if it is unripened (oddly enough).