| Chymosin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Crystal structure of bovine chymosin complex with the inhibitor CP-113972.[1] | |||||||||
| Identifiers | |||||||||
| EC no. | 3.4.23.4 | ||||||||
| CAS no. | 9001-98-3 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
Chymosin /ˈkaɪməsɪn/ or rennin /ˈrɛnɪn/ is a protease found in rennet. It is an aspartic endopeptidase belonging to MEROPS A1 family. It is produced by newborn ruminant animals in the lining of the abomasum to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. It is widely used in the production of cheese.
Historically, chymosin was obtained by extracting it from the stomachs of slaughtered calves. Today, most commercial chymosin used in cheese production is produced recombinantly in Escherichia coli, Aspergillus niger var. awamori, and Kluyveromyces lactis.[citation needed]
- ^ PDB: 1CZI; Groves MR, Dhanaraj V, Badasso M, Nugent P, Pitts JE, Hoover DJ, Blundell TL (October 1998). "A 2.3 A resolution structure of chymosin complexed with a reduced bond inhibitor shows that the active site beta-hairpin flap is rearranged when compared with the native crystal structure" (PDF). Protein Engineering. 11 (10): 833–40. doi:10.1093/protein/11.10.833. PMID 9862200.