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Modified β‐casein restores thermal reversibility of human carbonic anhydrase II: The salt bridge mechanism
Author(s) -
FallahBagheri Azadeh,
MoosaviMovahedi Ali Akbar,
Taghizadeh Mohammad,
Khodarahmi Reza,
Ma'mani Leila,
Bijari Nooshin,
Bohlooli Mousa,
Shafiee Abbas,
Sheibani Nader,
Saboury Ali Akbar
Publication year - 2013
Publication title -
biotechnology and applied biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 70
eISSN - 1470-8744
pISSN - 0885-4513
DOI - 10.1002/bab.1081
Subject(s) - chemistry , thermal stability , differential scanning calorimetry , casein , carbonic anhydrase , salt (chemistry) , reagent , salt bridge , nuclear chemistry , enzyme , organic chemistry , biochemistry , physics , gene , mutant , thermodynamics
Modified β‐casein (mβ‐ CN ) was investigated as an efficient additive for thermal reversibility of human carbonic anhydrase II ( HCA II) at p H 7.75. The mβ‐ CN was obtained via modification of β‐casein (β‐ CN ) acidic residues using Woodward's reagent K . The effects of mβ‐ CN on the reversibility and stability of HCA II were determined by differential scanning calorimetry, UV –vis, and 1‐anilinonaphthalene‐8‐sulfonic acid fluorescence spectroscopic methods. The mβ‐ CN , as an additive, enhanced thermal reversibility of HCA II by 33%. Together, our results indicated that mβ‐ CN is very efficient in decreasing thermal aggregation and enhancing the stability of HCA II. Using theoretical studies, we propose that the mechanism for thermal reversibility is mediated through formation of a salt bridge between the W oodward part of mβ‐ CN and the Z n ion of HCA II.