Papain family cysteine protease
Papain cartoon.png
Papain from Carica papaya
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BRENDA entry
NiceZyme view
KEGG entry
metabolic pathway

Papain, also known as papaya proteinase I, is a cysteine protease ( enzyme present in papaya (Carica papaya) and mountain papaya (Vasconcellea cundinamarcensis).

Papain family

Papain belongs to a family of related proteins with a wide variety of activities, including endopeptidases, aminopeptidases, dipeptidyl peptidases and enzymes with both exo- and endo-peptidase activity.[1] Members of the papain family are widespread, found in baculoviruses,[2] eubacteria, yeast, and practically all protozoa, plants and mammals.[1] The proteins are typically lysosomal or secreted, and proteolytic cleavage of the propeptide is required for enzyme activation, although bleomycin hydrolase is cytosolic in fungi and mammals.[3] Papain-like cysteine proteinases are essentially synthesised as inactive proenzymes (zymogens) with N-terminal propeptide regions. The activation process of these enzymes includes the removal of propeptide regions, which serve a variety of functions in vivo and in vitro. The pro-region is required for the proper folding of the newly synthesised enzyme, the inactivation of the peptidase domain and stabilisation of the enzyme against denaturing at neutral to alkaline pH conditions. Amino acid residues within the pro-region mediate their membrane association, and play a role in the transport of the proenzyme to lysosomes. Among the most notable features of propeptides is their ability to inhibit the activity of their cognate enzymes and that certain propeptides exhibit high selectivity for inhibition of the peptidases from which they originate.[4]

Other Languages
العربية: باباين
bosanski: Papain
català: Papaïna
Deutsch: Papain
español: Papaína
euskara: Papaina
فارسی: پاپئین
français: Papaïne
galego: Papaína
Bahasa Indonesia: Papain
italiano: Papaina
עברית: פפאין
қазақша: Папаин
Nederlands: Papaïne
日本語: パパイン
polski: Papaina
português: Papaína
русский: Папаин
српски / srpski: Papain
srpskohrvatski / српскохрватски: Papain
svenska: Papain
українська: Папаїн
Tiếng Việt: Papain