| Cysteine peptidase, CA clan | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 | |||||||||
| Identifiers | |||||||||
| Symbol | Peptidase_C1 | ||||||||
| Pfam | PF00112 | ||||||||
| Pfam clan | CL0125 | ||||||||
| InterPro | IPR000668 | ||||||||
| SMART | SM00645 | ||||||||
| PROSITE | PDOC00126 | ||||||||
| MEROPS | C1 | ||||||||
| SCOP2 | 1aec / SCOPe / SUPFAM | ||||||||
| OPM superfamily | 355 | ||||||||
| OPM protein | 1m6d | ||||||||
| |||||||||
Cysteine proteases, also known as thiol proteases, are hydrolase enzymes that degrade proteins. These proteases share a common catalytic mechanism that involves a nucleophilic cysteine thiol in a catalytic triad or dyad.[1]
Discovered by Gopal Chunder Roy in 1873, the first cysteine protease to be isolated and characterized was papain, obtained from Carica papaya.[1] Cysteine proteases are commonly encountered in fruits including the papaya, pineapple, fig and kiwifruit. The proportion of protease tends to be higher when the fruit is unripe. In fact, the latex of dozens of different plant families are known to contain cysteine proteases.[2] Cysteine proteases are used as an ingredient in meat tenderizers.
- ^ a b Rawat, Aadish; Roy, Mrinalini; Jyoti, Anupam; Kaushik, Sanket; Verma, Kuldeep; Srivastava, Vijay Kumar (August 2021). "Cysteine proteases: Battling pathogenic parasitic protozoans with omnipresent enzymes". Microbiological Research. 249: 126784. doi:10.1016/j.micres.2021.126784. ISSN 1618-0623. PMID 33989978. S2CID 234597200.
- ^ Domsalla A, Melzig MF (June 2008). "Occurrence and properties of proteases in plant latices". Planta Medica. 74 (7): 699–711. doi:10.1055/s-2008-1074530. PMID 18496785.