Description. PA125, 9001-73-4. Spectrum Chemical Papain, Powder, Purified , is a cysteine protease enzyme the is present in the papaya fruit. It is traditionnally used to break down meat fibers. It has more recently been used to dissociate cells in the early steps of cell culture preparation.apain is a popular folk remedy to reduce pain, inflammation, and swelling. It has also been used to improve digestion and to treat infections, diarrhea, and allergies.