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Effect of alkali halides on α‐chymotrypsin activity in the plastein reaction
Author(s) -
Lozano Pedro,
Combes Didier
Publication year - 1993
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740620307
Subject(s) - chemistry , substrate (aquarium) , alkali metal , hofmeister series , halide , aqueous solution , inorganic chemistry , chymotrypsin , catalysis , salt (chemistry) , enzyme , organic chemistry , trypsin , oceanography , geology
The influence of different alkali halides (LiF, LiCl. LiBr, NaF, NaCl, NaBr, KF, KCl and KBr) on α‐chymotrypsin‐catalysed plastein synthesis has been studied in aqueous medium at different substrate concentrations. The results showed an enhancing effect on the plastein synthesis enzyme action by the presence of salts, proportional to salt concentration, which was decreased when the substrate concentration was increased. Additionally, these facts allowed the ions to be classified as a function of their activation power (F − > Cl − > Br − : K + > Na + > Li + ), which was in agreement with the interpretation of the Hofmeister lyotropic series. The influence of the several phenomena produced by the presence of salts in the plastein reaction, such as, salt‐substrate interactions and water activity, as well as the presence of deactivated enzyme was also analysed. The obtained results showed that the substrate concentration is the most important factor, and the activating effect of salts could be simultaneously involved with both a structural change on the substrate conformation and a reduction of water activity into the reaction media, enhancing the catalytic capability of the α‐chymotrypsin towards a peptide synthesis action.