The kinetics of thermal inactivation of bovine carbonic anhydrase (BCA) was studied in a 50 mM Tris-HCl
buffer, pH 7.8 using p-nitrophenyl acetate as substrate in absorbance of 400 nm by UV-VIS spectrophotometry. The number
of conformational locks and inter-subunit amino acid residues of BCA were obtained by thermal inactivation analysis.
The cleavage bonds between dimers of BCA during thermal dissociation and type of interactions between specific amino
acid residues were also detected. The thermal inactivation curves were plotted in temperatures ranging between 40-70°C.
It was shown several phases for inactivation of BCA at 65°C. Analyses of the curves were done by the conformational
lock theory. The subunits are dissociated and several intermediates appear during inactivation through increasing the temperature
in comparison with native state. Dynamic light scattering measurements was done to study the changes in hydrodynamic
radius during thermal inactivation. Three distinct zones were shown in DLS data. Biochemical computation using
ligplot is performed to find the inter-subunit amino acid residues for BCA.
Keywords: Carbonic anhydrase, kinetics, conformational lock, thermal inactivation, intersubunit interactions, carbon dioxide, acetazolamide, Crystal structures, His 64, Neisseria bacterium
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Published on: 03 July, 2012
Page: [852 - 858]