The selectivity of chymosin action on αs1- and β-caseins in solution is modulated in cheese

The primary proteolysis of caseins by chymosin in Gouda cheese was assessed by identifying the peptides present in the watersoluble fraction of a starter-free cheese. The results show that the selectivity of chymosin, as observed in solution, is affected by the cheese environment. Of all known prefe...

Full description

Saved in:
Bibliographic Details
Published in:International dairy journal 1997, Vol.7 (1), p.47-54
Main Authors: Exterkate, Fred A., Lagerwerf, Fija M., Haverkamp, Johan, van Schalkwijk, Saskia
Format: Article
Language:English
Subjects:
alphaS1-casein
beta-casein
Biological and medical sciences
cheese environment
cheesemaking
chemical composition
chymosin
Chymosin specificity
cleavage sites
enzyme activity
enzyme substrate interactions
Food industries
Fundamental and applied biological sciences. Psychology
Gouda cheese
interactions
Milk and cheese industries. Ice creams
peptides
proteolysis
rennet
selectivity
αs1- and β-casein
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The primary proteolysis of caseins by chymosin in Gouda cheese was assessed by identifying the peptides present in the watersoluble fraction of a starter-free cheese. The results show that the selectivity of chymosin, as observed in solution, is affected by the cheese environment. Of all known preferred cleavage sites in α s1- and β-caseins in solution, the enzyme failed to cleave susceptible bonds in the C-terminal part of α s1-casein in cheese. While α s1-casein is a poorly structured molecule in buffered solution, a specific structural arrangement is believed to occur in cheese and to exclusively affect the accessibility of the segment which includes the bonds 164–165, 156–157 and 149–150 that are highly susceptible in solution. Initially unevenly distributed salt in Gouda cheese is responsible for a limited extent of aggregation of β-casein; it allows a relatively rapid degradation of the monomeric form during the first weeks of ripening. A broader specificity of chymosin on the accessible part of α s1-casein as well as on β-casein is observed in cheese than in solution; this most probably results from an effect of the cheese environment on the substrate and/or the enzyme which affects the interactions between forces regulating binding.
ISSN:0958-6946
1879-0143
DOI:10.1016/S0958-6946(96)00047-7