Chymosine 370905 29872845 2008-05-22T22:54:41Z Pixeltoo 12024 ! pov La '''chymosine''' ou '''rennine''' (ne pas confondre avec [[rénine]]) est une [[endopeptidase]] ({{N° EC|3.4.23.4}}) du suc gastrique des veaux, des nouveau-nés... permettant la digestion ''spécifique'' de la [[caséine]]. Pour fabriquer les fromages, on ajoute au [[lait]] de la chymosine de veau.<!--, or for making [[junket]]--> Cette enzyme réagit spécifiquement avec la κ-[[caséine]] à la surface des [[micelle]]s de caséine du lait, coupant la protéine entre la [[phénylalanine]] et la [[méthionine]]. Ceci en présence d'ions [[calcium]] provoque la coagulation des micelles de caséine, donnant un [[caillé]]. <!-- The soluble fragment (residules 106-169) which becomes part of the [[whey]] is known as [[glyco macro peptide]] and contains the [[glycosylation]] sites for kappa casein. The other component (residules 1-105) is insoluble. The traditional source of rennet is the [[abomasum]] (fourth [[stomach]]) of [[slaughter]]ed, milk-fed new-born [[calf|calves]] or other young [[ruminant]]s. It is also possible to produce rennet from [[fungus|fungi]]. In recent times, most commercial rennet is made from genetically modified [[yeast]] or [[bacterium|bacteria]], allowing the production of cheese that is considered [[vegetarian]]. This rennet is thought to yield greater consistency in cheese quality than traditional animal rennet. Another rennet substitute ''cynara'' (from wild thistle) is used in traditional cheese production throughout the [[Mediterranean]]. Sometimes, the terminology is more distinct, '''rennet''' being the stomach extract, while '''rennin''' or '''chymosin''' are names for the pure enzyme itself, which is the active ingredient in the extract.--> ==Voir aussi== * [[pepsine]] * [[présure]] == Liens externes== * {{en}} http://www.vegsoc.org/info/cheese.html * {{en}} [[Banque de données des protéines|PDB]] [http://www.rcsb.org/pdb/cgi/explore.cgi?pid=203441034360021&page=0&pdbId=1CMS 1CMS], bovine chymosin [[Catégorie:EC 3.4.23]] [[de:Chymosin]] [[en:Chymosin]] [[fi:Renniini]] [[is:Rennín]] [[it:Chimosina]]