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Proteolysis of α s1 ‐Casein by Papain in a Complex Environment. Influence of Ionic Strength on the Reaction Products
Author(s) -
SANOGO T.,
PAQUET D.,
AUBERT F.,
LINDEN G.
Publication year - 1990
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1990.tb05234.x
Subject(s) - chemistry , papain , isoelectric point , chromatography , hydrolysis , ionic strength , casein , sodium dodecyl sulfate , hydrolysate , salt (chemistry) , isoelectric focusing , sodium , electrophoresis , biochemistry , organic chemistry , enzyme , aqueous solution
The influence of NaCl on bovine α s1 ‐casein (α s1 ‐CN) hydrolysis by papain (EC 3.4.22.2) was studied at pH 6.5 and 40°C. The electrophoretic analysis in presence of sodium dodecyl sulfate (SDS), showed that α s1 ‐CN was sequentially hydrolyzed as the reaction time increased. The analysis by isoelectric focusing electrophoresis showed that after 1 min, the resulting peptides had their isoelectric point (pl) assessed between 4 and 9. With the increase of NaCl concentration, two peptides of apparent pl near pH 5 and 8.5 were progressively liberated. The chromatographic analysis by reverse phase HPLC showed that a major peak, observed after 1 min of reaction, persisted in the hydrolysates obtained in the presence of salt at all reaction times. It was concluded by the peptidic sequence determination that the hydrophobic C‐terminal region of α s1 ‐CN was not hydrolyzed in the presence of NaCl.