Impact of High-Pressure on Enzymes

Leszek Kulisiewicz, Andreas Wierschem, Cornelia Rauh, and Antonio Delgado 

Industrial High Pressure Api ications Proc ses, Equipment and St ety, First Edition. Edited by Rudolf E ers. 2012 Wiley-VCH Verlag GmbH Co. KGaA. Published 2012 by Wiley-VCH Verlag GmbH Co. KGaA. 

enzyme activity is not always unwanted. On the contrary, many industrial applications of enzymatic catalysts are known, including food processing (e.g., brewing, dairy, and starch industry) and chemical and pharmaceutical industry [9, 16-20]. However, this chapter is focused on the case of high-pressure processing of foods aimed at the prolongation of shelf life. Hence, the emphasis is placed on the inactivation of enzymes related to quality of food products. 

In this expression, JCis the equilibrium constant for a given chemical equilibrium and the reaction volume A V is the difference between the volumes of the final and initial states in any particular process, for example, due to a change in molecule packing, electrostatic action of charges, solvation, and hydration effects. From Eq. (9.1), it is clear that the sign of the reaction volume A V imposes the direction of equilibrium shifts induced by pressure. If A V is negative, the equilibrium shifts 

Similarly, pressure influences the rate of reactions, accelerating reactions with negative activation volume AV and decelerating reactions with positive activation volume, according to Eq. (9.2)  

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Generally it is possible to activate enzymes under pressure, but at high hydrostatic pressure a decrease in activity occures due to pressure induced inactivation. The impact of pressure on the reaction rates is quite complex because of the different susceptibilities of the catalytic steps. It should be useful to perform enzyme catalysed reactions under hydrostatic pressure because pressure and temperature can have contrary effects. 

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