title: Increased susceptibility of beta-glucosidase from the hyperthermophile Pyrococcus furiosus to thermal inactivation at higher pressures.
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.
authors.affiliation: Food and Bioprocess Engineering Group, Department of Agrotechnology and Food Sciences, Wageningen University and Research Centre, The Netherlands.
authors.forename: Marieke E
authors.initials: ME
authors.lastname: Bruins
authors.forename: Filip
authors.initials: F
authors.lastname: Meersman
authors.forename: Anja E M
authors.initials: AE
authors.lastname: Janssen
authors.forename: Karel
authors.initials: K
authors.lastname: Heremans
authors.forename: Remko M
authors.initials: RM
authors.lastname: Boom
mesh_terms: D019843:Archaeal Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011312:Pressure; D020027:Pyrococcus furiosus / Q000201:enzymology*; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D001617:beta-Glucosidase