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Keywords:

enzyme stability, ftir spectroscopy, high hydrostatic pressure, intermediate, thermophile, enzyme inactivation, escherichia-coli, proteins, stabilization, temperature, myoglobin, thermostability, denaturation, spectroscopy, aggregation, Science & Technology, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, FTIR spectroscopy, ENZYME INACTIVATION, ESCHERICHIA-COLI, PROTEINS, STABILIZATION, TEMPERATURE, MYOGLOBIN, THERMOSTABILITY, DENATURATION, SPECTROSCOPY, AGGREGATION, Archaeal Proteins, Enzyme Stability, Hydrogen-Ion Concentration, Kinetics, Pressure, Pyrococcus furiosus, Spectrophotometry, Spectroscopy, Fourier Transform Infrared, Thermodynamics, beta-Glucosidase, 0304 Medicinal and Biomolecular Chemistry, 0601 Biochemistry and Cell Biology, 1101 Medical Biochemistry and Metabolomics, 3101 Biochemistry and cell biology, 3205 Medical biochemistry and metabolomics, 3404 Medicinal and biomolecular chemistry

Abstract:

The stability of beta-glucosidase from the hyperthermophile Pyrococcus furiosus was studied as a function of pressure, temperature and pH. The conformational stability was monitored using FTIR spectroscopy, and the functional enzyme stability was monitored by inactivation studies. The enzyme proved to be highly piezostable and thermostable, with an unfolding pressure of 800 MPa at 85 degrees C. The tentative pressure-temperature stability diagram indicates that this enzyme is stabilized against thermal unfolding at low pressures. The activity measurements showed a two-step inactivation mechanism due to pressure that was most pronounced at lower temperatures. The first part of this inactivation took place at pressures below 300 MPa and was not visible as a conformational transition. The second transition in activity was concomitant with the conformational transition. An increase in pH from 5.5 to 6.5 was found to have a stabilizing effect.