The action of rennin on casein The disruption of the k-casein complex

Beeby, R.; Nitschmann, Hs. (1963). The action of rennin on casein The disruption of the k-casein complex. Journal of dairy research, 30(1), pp. 7-16. Cambridge University Press 10.1017/S0022029900011201

Preview

Text S0022029900011201.pdf - Published Version Available under License Publisher holds Copyright. Download (1MB) | Preview

Approximately 30% of the nitrogen of κ-casein was soluble at pH 4·7 after the protein had been treated with rennin at pH 7 while approximately 10% was soluble in 12% trichloroacetic acid (TCA). The material soluble in 12% TCA appeared at a slower rate initially than did the nitrogen soluble at pH 4·7 but as the reaction proceeded it was released more rapidly.

Treating κ-casein with urea, or repeated precipitation of the protein at pH 4·7, caused the formation of material insoluble at pH 7, apparently para-κ-casein. Both treatments appeared to free the same soluble fraction as does rennin acting in low concentration or for a short time.

Low concentrations of rennin (0·07 μg/ml) released only part of the available soluble nitrogen from 2% solutions of whole casein at pH 7. Heating the reaction mixture appeared to restore the casein complex, the restoration being less complete the longer the reaction had proceeded.

It is suggested that κ-casein is not a single protein but a complex, and that the action of rennin is first to open the secondary bonds responsible for the stability of this complex.

Interest & Impact

Downloads

163 since deposited on 09 Jul 2020
27 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item