Chymosin
| Chymosin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
ExPASy NiceZyme view | | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
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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]
Occurrence
Chymosin is found in a wide range of
One study reported finding a chymosin-like enzyme in some human infants,: 262
In addition to the primate lineage leading up to humans, some other mammals have also lost the chymosin gene.[2]
Enzymatic reaction
Chymosin is used to bring about the extensive
Charge interactions between
Examples
Listed below are the ruminant Cym gene and corresponding human pseudogene:
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Recombinant chymosin
Because of the imperfections and scarcity of microbial and animal rennets, producers sought replacements. With the development of genetic engineering, it became possible to extract rennet-producing genes from animal stomach and insert them into certain
FPC was the first artificially produced enzyme to be registered and allowed by the
By 2008, approximately 80% to 90% of commercially made cheeses in the US and Britain were made using FPC.[13] The most widely used fermentation-produced chymosin is produced either using the fungus Aspergillus niger or using Kluyveromyces lactis.
FPC contains only chymosin B,[17] achieving a higher degree of purity compared with animal rennet. FPC can deliver several benefits to the cheese producer compared with animal or microbial rennet, such as higher production yield, better curd texture and reduced bitterness.[14]
References
- ^ PMID 9862200.
- ^ PMID 28851538.
- S2CID 7552821.
- ^ a b Staff, Online Mendelian Inheritance in Man (OMIM) Database. Last updated February 21, 1997 Chymosin pseudogene; CYMP prochymosin, included, in the OMIM
- PMID 3118972.
- .
- ISBN 9780834213388.
- ISBN 978-1-55009-081-9.
- ^ PMID 1812710.
- PMID 1942052.
- PMID 6304731.
- PMID 6283469.
- ^ a b "Chymosin". GMO Compass. Archived from the original on 2015-03-26. Retrieved 2011-03-03.
- ^ ISBN 978-1-4051-8298-0.
- ^ "Food Biotechnology in the United States: Science, Regulation, and Issues". U.S. Department of State. Retrieved 2006-08-14.
- PMID 16537950.
- ^ Bovine chymosins A and B differ by one amino acid residue. This is probably an alleic variant, according to Uniprot:P00794. The two isoforms have identical catalytic activity, so any improvement in the product is due to the elimination of other impurities.
Further reading
- Foltmann B (1966). "A review on prorennin and rennin". Comptes-Rendus des Travaux du Laboratoire Carlsberg. 35 (8): 143–231. PMID 5330666.
- Visser S, Slangen CJ, van Rooijen PJ (June 1987). "Peptide substrates for chymosin (rennin). Interaction sites in kappa-casein-related sequences located outside the (103-108)-hexapeptide region that fits into the enzyme's active-site cleft". The Biochemical Journal. 244 (3): 553–8. PMID 3128264.
