Hydrolytic reactions in two-phase systems. Effect of water-immiscible organic solvents on stability and activity of acid phosphatase, β-glucosidase, and β-fructofuranosidase

Abstract

The stability and activity of three hydrolytic enzymes, acid phosphatase (EC 3.1.3.2), β-fructofuranosidase (EC 3.2.1.26), and β-glucosidase (EC 3.2.1.4), were studied at 30°C in two-phase systems. They were prepared with equal quantities of buffered water and a water-immiscible organic solvent. Lowmolecular-weight acetates and paraffins were tested in this investigation. The kinetic constant of storage inactivation was correlated with the logarithm of solvent polarity. Enzyme stability in the presence of organic phases, whose log P value was included in 1.2–2.2, was greater than the one measured in pure buffered aqueous media. On the other hand, a dramatic enzyme denaturation took place making use of solvents at higher log P-value. Experiments carried out during the 24-h operation clarified that the reaction yield does not depend solely on solvent polarity. Acid phosphatase and β-glucosidase, which are less resistant than β-fructofuranosidase to temperature and shear in buffered solutions, showed especially significant enhancement of catalytic activity when hydrolysis was performed with the addition of acetates (50% v/v).