|Ref Sequence ID
|Protein Existence Status
|Presence in other biological fluids/tissue/cells
|in the abomasum of calves and the stomach of human infants which clots milk by precipitation of the casein
|Chymosin is synthesized in the mucosa of the abomasum (fourth stomach) of young (unweaned) ruminants. The enzymehas endopeptidase activity which hydrolyzes casein to paracasein.
|Broad specificity similar to that of pepsin A. Clots milk by cleavage of a single 104-Ser-Phe-|-Met-Ala-107 bond in kappa-chain of casein.The substrate affinity and catalytic activity of bovine chymosin increase at lower pH (6.00 and 5.50).Chymosin proteolytically cuts and inactivates kappa casein, converting it into para-kappa-casein and a smaller protein called macropeptide. Para-kappa-casein does not have the ability to stabilize the micellar structure and the calcium-insoluble caseins precipitate, forming a curd.
|Significance in milk
|is secreted in the neonatal stomach of ruminants.Function is to curdle or coagulate milk.chymosin is also a very important industrial enzyme because it is widely used in cheesemaking.
|Disulfide bond formation,Proteolytic cleavage
| Site(s) of PTM(s)
| Class : All beta proteins
Fold : Acid proteases
Superfamily : Acid proteases
Family : Pepsin-like
Domain Name : 1CMS A:1-323
| Matched CATH superfamily
|Predicted Disorder Regions
|TM Helix Prediction
|No TM helices
|Jensen JL, Jacobsen J, Moss ML, Rasmussen F, Qvist KB, Larsen S, van den Brink JM. The function of the milk-clotting enzymes bovine and camel chymosin studied by a fluorescence resonance energy transfer assay. J Dairy Sci. 2015 May;98(5):2853-60. doi: 10.3168/jds.2014-8672. Epub 2015 Feb 26. PMID: 25726113.