title: Generating favorable nano-environments for thermal and solvent stabilization of immobilized beta-galactosidase.
abstract: beta-Galactosidase (Escherichia coli) was immobilized through its thiol groups on thiolsulfinate-agarose gel. After enzyme immobilization, different nano-environments were generated by reacting the excess of gel-bound thiolsulfinate moieties with 2-mercaptoethanesulfonic acid (S-gel), glutathione (G-gel), cysteamine (C-gel), and mercaptoethanol (M-gel). Concerning thermal stability at 50 degrees C, the G-gel and the M-gel derivatives were the most stable with residual activity values of 67% and 45%, respectively. The stability in several solvent systems was studied: ethyl acetate (1.6% vol/vol), ethylene glycol (50% vol/vol), and 2-propanol (50% vol/vol). In ethyl acetate, both the M-gel and S-gel were highly stabilized; the time required for activity to decay to 80% of the initial activity was increased 29-fold for the M-gel and 20-fold for the S-gel with respect to the soluble enzyme. The G-gel was the least stable of all the derivatives. The different behaviors of the derivatives in thermal and solvent stability studies suggest that each nano-environment contributes differently to the enzyme stability, depending on the denaturing conditions. Therefore, it may be possible to tailor the matrix surface to maximize enzyme stability in particular applications.
authors.affiliation: Cátedra de Bioquímica, Facultad de Química, Gral. Flores 2124, CC 1157, Montevideo, Uruguay.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Irazoqui
authors.forename: Andrea
authors.initials: A
authors.lastname: Villarino
authors.forename: Francisco
authors.initials: F
authors.lastname: Batista-Viera
authors.forename: Beatriz M
authors.initials: BM
authors.lastname: Brena
mesh_terms: D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry; D004795:Enzyme Stability / Q000502:physiology; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D005782:Gels / Q000737:chemistry; D006358:Hot Temperature; D036103:Nanotechnology / Q000379:methods*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013441:Sulfinic Acids / Q000737:chemistry; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D004800:Enzymes, Immobilized; D005782:Gels; D012997:Solvents; D013441:Sulfinic Acids; C100040:thiosulfinic acids; D001616:beta-Galactosidase