Not to be confused with renin, an enzyme which takes part in regulation of arterial blood pressure.
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.
Chymosin
Crystal structure of bovine chymosin complex with the inhibitor CP-113972.[1]
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 E. coli, Aspergillus niger var awamori, and K. lactis.
Chymosin is found in a wide range of tetrapods,[2] although it is best known to be produced by ruminant animals in the lining of the abomasum. Chymosin is produced by gastric chief cells in newborn mammals[3] to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. Non-ruminant species that produce chymosin include pigs, cats, seals,[4] and chicks.[2]
One study reported finding a chymosin-like enzyme in some human infants,[5] but others have failed to replicate this finding.[6] Humans have a pseudogene for chymosin that does not generate a protein, found on chromosome 1.[4][7] Humans have other proteins to digest milk, such as pepsin and lipase.[8]: 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 precipitation and curd formation in cheese-making. The native substrate of chymosin is K-casein which is specifically cleaved at the peptide bond between amino acid residues 105 and 106, phenylalanine and methionine.[9] The resultant product is calcium phosphocaseinate.[citation needed] When the specific linkage between the hydrophobic (para-casein) and hydrophilic (acidic glycopeptide) groups of casein is broken, the hydrophobic groups unite and form a 3D network that traps the aqueous phase of the milk.
Charge interactions between histidines on the kappa-casein and glutamates and aspartates of chymosin initiate enzyme binding to the substrate.[9] When chymosin is not binding substrate, a beta-hairpin, sometimes referred to as "the flap," can hydrogen bond with the active site, therefore covering it and not allowing further binding of substrate.[1]
Examples
Listed below are the ruminant Cym gene and corresponding human pseudogene:
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 bacteria, fungi or yeasts to make them produce chymosin during fermentation.[11][12] The genetically modified microorganism is killed after fermentation and chymosin is isolated from the fermentation broth, so that the fermentation-produced chymosin (FPC) used by cheese producers does not contain any GM component or ingredient.[13] FPC contains the identical chymosin as the animal source, but produced in a more efficient way. FPC products have been on the market since 1990 and are considered the ideal milk-clotting enzyme.[14]
FPC was the first artificially produced enzyme to be registered and allowed by the US Food and Drug Administration. In 1999, about 60% of US hard cheese was made with FPC[15] and it has up to 80% of the global market share for rennet.[16]
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
^ abPDB: 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.
^ abcLopes-Marques M, Ruivo R, Fonseca E, Teixeira A, Castro LF (November 2017). "Unusual loss of chymosin in mammalian lineages parallels neo-natal immune transfer strategies". Molecular Phylogenetics and Evolution. 116: 78–86. doi:10.1016/j.ympev.2017.08.014. PMID 28851538.
^Kitamura N, Tanimoto A, Hondo E, Andrén A, Cottrell DF, Sasaki M, Yamada J (August 2001). "Immunohistochemical study of the ontogeny of prochymosin--and pepsinogen-producing cells in the abomasum of sheep". Anatomia, Histologia, Embryologia. 30 (4): 231–5. doi:10.1046/j.1439-0264.2001.00326.x. PMID 11534329. S2CID 7552821.
^ abStaff, Online Mendelian Inheritance in Man (OMIM) Database. Last updated February 21, 1997 Chymosin pseudogene; CYMP prochymosin, included, in the OMIM
^Henschel MJ, Newport MJ, Parmar V (1987). "Gastric proteases in the human infant". Biology of the Neonate. 52 (5): 268–72. doi:10.1159/000242719. PMID 3118972.
^Szecsi PB, Harboe M (2013). "Chapter 5: Chymosin". In Rawlings ND, Salvesen G (eds.). Handbook of Proteolytic Enzymes. Vol. 1. pp. 37–42. doi:10.1016/B978-0-12-382219-2.00005-3.
^Fox PF (28 February 1999). Cheese: Chemistry, Physics and Microbiology. ISBN9780834213388.
^Sanderson IR, Walker WA (1999). Development of the gastrointestinal tract. Hamilton, Ontario: B.C. Decker. ISBN978-1-55009-081-9.
^ abGilliland GL, Oliva MT, Dill J (1991). "Functional implications of the three-dimensional structure of bovine chymosin". Advances in Experimental Medicine and Biology. 306: 23–37. doi:10.1007/978-1-4684-6012-4_3. ISBN978-1-4684-6014-8. PMID 1812710.
^PDB: 4CMS; Newman M, Safro M, Frazao C, Khan G, Zdanov A, Tickle IJ, et al. (October 1991). "X-ray analyses of aspartic proteinases. IV. Structure and refinement at 2.2 A resolution of bovine chymosin". Journal of Molecular Biology. 221 (4): 1295–309. doi:10.1016/0022-2836(91)90934-X. PMID 1942052.
^Emtage JS, Angal S, Doel MT, Harris TJ, Jenkins B, Lilley G, Lowe PA (June 1983). "Synthesis of calf prochymosin (prorennin) in Escherichia coli". Proceedings of the National Academy of Sciences of the United States of America. 80 (12): 3671–5. Bibcode:1983PNAS...80.3671E. doi:10.1073/pnas.80.12.3671. PMC394112. PMID 6304731.
^Harris TJ, Lowe PA, Lyons A, Thomas PG, Eaton MA, Millican TA, et al. (April 1982). "Molecular cloning and nucleotide sequence of cDNA coding for calf preprochymosin". Nucleic Acids Research. 10 (7): 2177–87. doi:10.1093/nar/10.7.2177. PMC320601. PMID 6283469.
^ ab. GMO Compass. Archived from the original on 2015-03-26. Retrieved 2011-03-03.
^ abLaw BA (2010). Technology of Cheesemaking. UK: Wiley-Blackwell. pp. 100–101. ISBN978-1-4051-8298-0.
^"Food Biotechnology in the United States: Science, Regulation, and Issues". U.S. Department of State. Retrieved 2006-08-14.
^Johnson ME, Lucey JA (April 2006). "Major technological advances and trends in cheese". Journal of Dairy Science. 89 (4): 1174–8. doi:10.3168/jds.S0022-0302(06)72186-5. 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. doi:10.1042/bj2440553. PMC1148031. PMID 3128264.
External links
The MEROPS online database for peptidases and their inhibitors: A01.006
chymosin, confused, with, renin, enzyme, which, takes, part, regulation, arterial, blood, pressure, rennin, protease, found, rennet, aspartic, endopeptidase, belonging, merops, family, produced, newborn, ruminant, animals, lining, abomasum, curdle, milk, they,. Not to be confused with renin an enzyme which takes part in regulation of arterial blood pressure Chymosin ˈ k aɪ m e s ɪ n or rennin ˈ r ɛ n ɪ n 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 ChymosinCrystal structure of bovine chymosin complex with the inhibitor CP 113972 1 IdentifiersEC no 3 4 23 4CAS no 9001 98 3DatabasesIntEnzIntEnz viewBRENDABRENDA entryExPASyNiceZyme viewKEGGKEGG entryMetaCycmetabolic pathwayPRIAMprofilePDB structuresRCSB PDB PDBe PDBsumGene OntologyAmiGO QuickGOSearchPMCarticlesPubMedarticlesNCBIproteinsHistorically chymosin was obtained by extracting it from the stomachs of slaughtered calves Today most commercial chymosin used in cheese production is produced recombinantly in E coli Aspergillus niger var awamori and K lactis Contents 1 Occurrence 2 Enzymatic reaction 3 Examples 4 Recombinant chymosin 5 References 6 Further reading 7 External linksOccurrence EditChymosin is found in a wide range of tetrapods 2 although it is best known to be produced by ruminant animals in the lining of the abomasum Chymosin is produced by gastric chief cells in newborn mammals 3 to curdle the milk they ingest allowing a longer residence in the bowels and better absorption Non ruminant species that produce chymosin include pigs cats seals 4 and chicks 2 One study reported finding a chymosin like enzyme in some human infants 5 but others have failed to replicate this finding 6 Humans have a pseudogene for chymosin that does not generate a protein found on chromosome 1 4 7 Humans have other proteins to digest milk such as pepsin and lipase 8 262 In addition to the primate lineage leading up to humans some other mammals have also lost the chymosin gene 2 Enzymatic reaction EditChymosin is used to bring about the extensive precipitation and curd formation in cheese making The native substrate of chymosin is K casein which is specifically cleaved at the peptide bond between amino acid residues 105 and 106 phenylalanine and methionine 9 The resultant product is calcium phosphocaseinate citation needed When the specific linkage between the hydrophobic para casein and hydrophilic acidic glycopeptide groups of casein is broken the hydrophobic groups unite and form a 3D network that traps the aqueous phase of the milk Charge interactions between histidines on the kappa casein and glutamates and aspartates of chymosin initiate enzyme binding to the substrate 9 When chymosin is not binding substrate a beta hairpin sometimes referred to as the flap can hydrogen bond with the active site therefore covering it and not allowing further binding of substrate 1 Examples EditListed below are the ruminant Cym gene and corresponding human pseudogene Chymosin Precursor X ray analysis of calf chymosin 10 IdentifiersOrganismBos taurusSymbolCymAlt symbolsCPCEntrez529879PDB4CMSUniProtP00794Search forStructuresSwiss modelDomainsInterPro chymosin pseudogene human IdentifiersSymbolCYMPNCBI gene643160HGNC2588OMIM118943RefSeqNR 003599Other dataLocusChr 1 p13 3Recombinant chymosin EditBecause 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 bacteria fungi or yeasts to make them produce chymosin during fermentation 11 12 The genetically modified microorganism is killed after fermentation and chymosin is isolated from the fermentation broth so that the fermentation produced chymosin FPC used by cheese producers does not contain any GM component or ingredient 13 FPC contains the identical chymosin as the animal source but produced in a more efficient way FPC products have been on the market since 1990 and are considered the ideal milk clotting enzyme 14 FPC was the first artificially produced enzyme to be registered and allowed by the US Food and Drug Administration In 1999 about 60 of US hard cheese was made with FPC 15 and it has up to 80 of the global market share for rennet 16 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 Edit a b 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 a b c Lopes Marques M Ruivo R Fonseca E Teixeira A Castro LF November 2017 Unusual loss of chymosin in mammalian lineages parallels neo natal immune transfer strategies Molecular Phylogenetics and Evolution 116 78 86 doi 10 1016 j ympev 2017 08 014 PMID 28851538 Kitamura N Tanimoto A Hondo E Andren A Cottrell DF Sasaki M Yamada J August 2001 Immunohistochemical study of the ontogeny of prochymosin and pepsinogen producing cells in the abomasum of sheep Anatomia Histologia Embryologia 30 4 231 5 doi 10 1046 j 1439 0264 2001 00326 x PMID 11534329 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 Henschel MJ Newport MJ Parmar V 1987 Gastric proteases in the human infant Biology of the Neonate 52 5 268 72 doi 10 1159 000242719 PMID 3118972 Szecsi PB Harboe M 2013 Chapter 5 Chymosin In Rawlings ND Salvesen G eds Handbook of Proteolytic Enzymes Vol 1 pp 37 42 doi 10 1016 B978 0 12 382219 2 00005 3 Fox PF 28 February 1999 Cheese Chemistry Physics and Microbiology ISBN 9780834213388 Sanderson IR Walker WA 1999 Development of the gastrointestinal tract Hamilton Ontario B C Decker ISBN 978 1 55009 081 9 a b Gilliland GL Oliva MT Dill J 1991 Functional implications of the three dimensional structure of bovine chymosin Advances in Experimental Medicine and Biology 306 23 37 doi 10 1007 978 1 4684 6012 4 3 ISBN 978 1 4684 6014 8 PMID 1812710 PDB 4CMS Newman M Safro M Frazao C Khan G Zdanov A Tickle IJ et al October 1991 X ray analyses of aspartic proteinases IV Structure and refinement at 2 2 A resolution of bovine chymosin Journal of Molecular Biology 221 4 1295 309 doi 10 1016 0022 2836 91 90934 X PMID 1942052 Emtage JS Angal S Doel MT Harris TJ Jenkins B Lilley G Lowe PA June 1983 Synthesis of calf prochymosin prorennin in Escherichia coli Proceedings of the National Academy of Sciences of the United States of America 80 12 3671 5 Bibcode 1983PNAS 80 3671E doi 10 1073 pnas 80 12 3671 PMC 394112 PMID 6304731 Harris TJ Lowe PA Lyons A Thomas PG Eaton MA Millican TA et al April 1982 Molecular cloning and nucleotide sequence of cDNA coding for calf preprochymosin Nucleic Acids Research 10 7 2177 87 doi 10 1093 nar 10 7 2177 PMC 320601 PMID 6283469 a b Chymosin GMO Compass Archived from the original on 2015 03 26 Retrieved 2011 03 03 a b Law BA 2010 Technology of Cheesemaking UK Wiley Blackwell pp 100 101 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 Johnson ME Lucey JA April 2006 Major technological advances and trends in cheese Journal of Dairy Science 89 4 1174 8 doi 10 3168 jds S0022 0302 06 72186 5 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 EditFoltmann 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 doi 10 1042 bj2440553 PMC 1148031 PMID 3128264 External links EditThe MEROPS online database for peptidases and their inhibitors A01 006 Portal Biology Retrieved from https en wikipedia org w index php title Chymosin amp oldid 1152527545, wikipedia, wiki, book, books, library,
