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Thermal stabilization of carboxypeptidase a as a function of pH and ionic milieu
Author(s) -
Li Xinhui,
Solomon Beka
Publication year - 1997
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549700204411
Subject(s) - thermostability , chemistry , carboxypeptidase , carboxypeptidase a , ionic bonding , thermal stability , salt bridge , sodium , phosphate , salt (chemistry) , enzyme , arginine , inorganic chemistry , biochemistry , organic chemistry , ion , amino acid , mutant , gene
In this study we investigated the contribution of pH, phosphate anions and salt concentration to the catalytic and structural thermostability of the carboxypeptidase A (CPA). The concentration of 75‐100 mM phosphate as well as neutral pH values were found to be optimal for stabilizing CPA at high temperatures. Although moderate concentrations of sodium chloride had no effect on thermal stability, high concentrations of the salt destabilized the enzyme. The experimental results and theoretical analysis suggested that the main contribution to heat stabilization of CPA is related to intramolecular electrostatic interactions and Arginine and/or Lysine are the putative groups able to bind phosphate and stabilize the enzyme molecule against thermal denaturation.