Premium
Proteolysis of α s1 ‐Casein by Papain in a Complex Environment. Influence of Ionic Strength on the Kinetic Constants
Author(s) -
SANOGO T.,
PAQUET D.,
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.tb05235.x
Subject(s) - casein , ionic strength , papain , chemistry , substrate (aquarium) , urea , hydrolysis , kinetics , michaelis–menten kinetics , chromatography , reaction rate constant , enzyme , nuclear chemistry , analytical chemistry (journal) , enzyme assay , biochemistry , organic chemistry , aqueous solution , biology , quantum mechanics , ecology , physics
The influence of α s1 ‐casein concentration on the hydrolytic activity of papain was studied. High substrate concentration was inhibitory. In presence of NaCl, the papain affinity for α s1 ‐casein increased (the apparent Michaelis constant (K m . app.) decreased from 9.4 10 −5 to 5.6 10 −5 M) and was lower for 0.08M NaCl. The maximum velocity (V max app‐) was independant from NaCl concentration below 0.34M but decreased above. The enzyme‐substrate affinity was increased by the addition of urea, but the V max app. decreased. The inhibitory effect of excess substrate was more important with the presence of both urea and NaCl. Acetylation of α s1 ‐casein showed that K m. app. (21.2 10 −5 M) was independant of salt concentration, while the V max app. varied, and the substrate inhibitory activity was suppressed.