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Thermodynamics and Extra‐thermodynamics of Bacillus subtilis α ‐Amylase in Some Chromatographic Systems
Author(s) -
BIAN Liujiao,
WANG Xiaohua,
YANG Xiaoyan,
LIU Li,
CHEN Chao
Publication year - 2009
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200990087
Subject(s) - chemistry , enthalpy , thermodynamics , atmospheric temperature range , gibbs free energy , adsorption , enthalpy of fusion , chromatography , organic chemistry , melting point , physics
The thermodynamics and extra‐thermodynamics of Bacillus subtilis α ‐amylase in five kinds of chromatographic systems were studied by determining their adsorption equilibrium constant K SL , enthalpy change, entropy change, free energy change and compensation temperature under different temperature areas. The results showed that on an RP‐C 18 reversed‐phase medium, a Zn‐chelated Sepharose fast‐flow affinity medium and a WCX‐1 cation‐exchange medium, their ln K SL separately linearly changed with the reciprocal of absolute temperatures under two different temperature ranges of 13–30 and 30–50 °C; and on PEG‐400 and modified PEG‐400 hydrophobic media, their ln K SL separately linearly decreased with the reciprocal of absolute temperatures under the temperature areas of 13–40 and 13–30 °C, while when the temperatures were separately over 40 and 30 °C, they violently decreased with the reciprocal of absolute temperatures. Through studying the relations among the enthalpy change, entropy change, free energy change and the conformational change of α ‐amylase under the different temperature areas, it was found that on the RP‐C 18 reversed‐phase medium and Zn‐chelated Sepharose fast‐flow affinity medium under the temperature range of 30–50 °C and on the WCX‐1 cation‐exchange medium under the temperature range of 13–30 °C, their adsorption procedures were driven by both the enthalpy change and the entropy change; while on the Zn‐chelated Sepharose fast‐flow affinity medium under the temperature range of 13–30 °C, on the WCX‐1 cation‐exchange medium under the temperature range of 30–50 °C and on the PEG‐400 and modified PEG‐400 hydrophobic media under the temperature range of 13–65 °C, their adsorption procedures were driven only by the entropy change. Finally, by comparing the compensation temperatures of α ‐amylase in these chromatographic systems each other, it was further found that their enthalpy changes could be compensated only with their entropy changes rising from their conformational change.