Modeled of the effect of different organic solvents on the residual activity of araujiain and papaina in biphasic system.

EVELINA QUIROGA; SONIA BARBERIS; MARÍA CECILIA ARRIBÉRE; NORA PRIOLO.

San Carlos de Bariloche, Argentina

Congreso; XXXIX Encuentro Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2003

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

In this work we study the effect of different water-immiscible organic solvents on the residual caseinolytic activity of araujiain and papain in aqueous-organic biphasic systems.   Those enzymes showed greater residual activity in some biphasic media than in water and an important decrease of the autolysis degree in the presence of some organic solvents.  This effect could be related to the variation of the flexibility and/or conformational changes of enzymes in the absence of a pure aqueous phase. Exceptionally, some organic solvents inactivated those enzymes due to the toxicity of the organic solvent molecules dissolved in the aqueous phase (molecular toxicity) and/or the presence of a separate organic phase (phase toxicity). We modeled the residual activity of araujiain and papain in aqueous-organic biphasic systems as a function of physico-chemical properties of the organic solvents. The generalized belief that organic solvents with log P > 4 causes less inactivation than hydrophilic ones could not be verified.  A single–parameter approach was limited in its ability to reflect the possible enzyme-solvent interactions but correlation which combines dielectric constant, dipole moment, solvent dipolarity/polarizability, and refraction index, were useful for predicting residual caseinolytic activity of  those enzymes in aqueous-organic bipasic systems.