Claude Balny

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Elevated hydrostatic pressure has been used to increase catalytic activity and thermal stability of alpha-chymotrypsin (CT). For an anilide substrate, characterized by a negative value of the reaction activation volume (DeltaV( not equal)), an increase in pressure at 20 degrees C results in an exponential acceleration of the hydrolysis rate catalyzed by CT(More)
High-pressure (HP)biotechnology is an emerging technique initially applied for foodprocessing andmore recently in pharmaceutical and medical sciences. Pressure can stabilize enzymes and modulate both their activity and specificity. HP engineering of proteins may be used for enzyme-catalyzed synthesis of fine chemicals, pharmaceuticals, and production of(More)
The kinetics of electron-transfer involved in reactions of reduction of 2,6-dichlorophenol indophenol and Fe(CN)3-(6) by L-ascorbic acid and reduction of ferric cytochrome c by both L-ascorbic acid and reduced hydroxylamine oxidoreductase were studied as a function of three parameters: ionic strength, pressure (1-2000 bar) and temperature (4-20 degrees C)(More)
Two different types of insoluble, non-native aggregates of recombinant human growth hormone were formed by agitation in buffer or buffer containing 0.75 m guanidine HCl (GdnHCl) and characterized by infrared and second derivative UV spectroscopies. The degree of secondary structural perturbation was greater in the aggregates formed in 0.75 m GdnHCl. Both(More)
Hydroxylamine oxidoreductase (HAO) of Nitrosomonas catalyzes the dehydrogenation of NH2OH and subsequent addition of oxygen to form nitrite. HAO contains c hemes and the CO-binding heme P460 in a 7:1 ratio; dehydrogenation of NH2OH involves passage of electrons to P460 and then c hemes. We now report that electrons rapidly pass from c hemes of HAO to the(More)
The pressure dependence of enzyme catalytic parameters allows volume changes associated with substrate binding and activation volumes for the chemical steps to be determined. Because catalytic constants are composite parameters, elementary volume change contributions can be calculated from the pressure differentiation of kinetic constants. Linear and(More)
Denaturation of the Saccharomyces cerevisiae prion protein Ure2 was investigated using hydrostatic pressure. Pressures of up to 600 MPa caused only limited perturbation of the structure of the 40-kDa dimeric protein. However, nondenaturing concentrations of GdmCl in combination with high pressure resulted in complete unfolding of Ure2 as judged by intrinsic(More)