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Deactivation of TEM‐1 β‐Lactamase Investigated by Isothermal Batch and Non‐Isothermal Continuous Enzyme Membrane Reactor Methods
Author(s) -
Rogers Thomas A.,
Daniel Roy M.,
Bommarius Andreas S.
Publication year - 2009
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.200900120
Subject(s) - isothermal process , membrane reactor , chemistry , thermodynamics , membrane , melting point , immobilized enzyme , enzyme , materials science , chemical engineering , organic chemistry , biochemistry , physics , engineering
The thermal deactivation of TEM‐1 β‐lactamase was examined using two experimental techniques: a series of isothermal batch assays and a single, continuous, non‐isothermal assay in an enzyme membrane reactor (EMR). The isothermal batch‐mode technique was coupled with the three‐state “Equilibrium Model” of enzyme deactivation, while the results of the EMR experiment were fitted to a four‐state “molten globule model”. The two methods both led to the conclusions that the thermal deactivation of TEM‐1 β‐lactamase does not follow the Lumry‐Eyring model and that the T eq of the enzyme (the point at which active and inactive states are present in equal amounts due to thermodynamic equilibrium) is at least 10 °C from the T m (melting temperature), contrary to the idea that the true temperature optimum of a biocatalyst is necessarily close to the melting temperature.