Chymosin 67167 212152696 2008-05-13T17:32:10Z 68.210.12.103 {{protein |Name=Chymosin [Precursor] (''B.taurus'' or ''C.dromedarius'') |caption= |image= |width= |HGNCid= |Symbol=CYM |AltSymbols=CPC |EntrezGene=529879 |OMIM= |RefSeq=NP_851337.1 |UniProt=Q9GK11 |PDB=4CMS |ECnumber=3.4.23.4 |Chromosome=3 |Arm= |Band= |LocusSupplementaryData= }} {{protein |Name=chymosin pseudogene (''H.sapiens'') |caption= |image= |width= |HGNCid=2588 |Symbol=CYMP |AltSymbols= |EntrezGene=1542 |OMIM=118943 |RefSeq= |UniProt= |PDB= |ECnumber=3.4.23.4 |Chromosome=1 |Arm= |Band= |LocusSupplementaryData= }} '''Chymosin''' (or '''rennin''') is an [[Aspartic acid proteases|aspartic acid protease]] [[enzyme]] found in [[rennet]]. It is produced by the cow, in the lining of the [[abomasum]] (its fourth stomach). Bovine chymosin is produced nowadays recombinantly in ''[[E.coli]]'', ''[[Aspergillus niger |Aspergillus niger var awamori]]'', and ''[[K.lactis]]'' as alternative resource to the one from the cows. The gene is found in humans (on [[chromosome 1]]), but it is not in a functioning form. Rennin is produced by gastric chief cells in infants to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. ==Enzymatic reaction== It causes [[cleavage]] of a specific linkage, the [[peptide bond]] between [[phenylalanine]] and [[methionine]] in the [[K-casein]]. If this reaction applies to milk, the specific linkage between the [[hydrophobic]] (para-casein) and [[hydrophilic]] (acidic [[glycopeptide]]) group of [[casein]] inside milk would be broken, since they are joined by phenylalanine and methionine. The hydrophobic group would unite together and would form a [[Three-dimensional space|3D]] network to trap the aqueous phase of the milk. The resultant product is [[calcium phosphocaseinate]]. Due to this reaction, rennin is used to bring about the extensive [[Precipitation (chemistry)|precipitation]] and [[curd]] formation in [[cheese]] making. [[de:Chymosin]] [[fr:Chymosine]] [[is:RennĂ­n]] [[it:Chimosina]] [[fi:Renniini]]