title: Co-aggregation of penicillin g acylase and polyionic polymers: an easy methodology to prepare enzyme biocatalysts stable in organic media.
abstract: A novel type of biocatalyst that combines the good properties of cross-linked enzyme aggregates (CLEAs) and hydrophilic microenvironments has been developed. Dextran sulfate- and polyethyleneimine-coated CLEAs of penicillin acylase (CLEA-GDP) were prepared by adding the polymers of different sizes before the precipitation stage of the enzyme. This study presents the development and optimization of a protocol to produce such a biocatalyst using penicillin acylase as a model. Experiments show that CLEA-GDPs have a highly increased stability in organic media. The average half-life of the preparations was much higher than standard CLEA without a microenvironment (CLEA-G), (e.g., more than 25-fold) in the presence of dioxane. However, their thermal stability was not increased, which leads to the conclusion that the stability of CLEA-GDPs in organic media is due to the hydrophilic microenvironment that surrounds the protein enzyme more than to a conformational stiffening effect. This is further supported by solvation experiments that show a preferential hydration of CLEA when polymers are used to coat the enzyme. CLEA-GDPs are clearly better than other biocatalysts in terms of solvent stability.
authors.affiliation: Departamento de Biocatalisis, Instituto de Catalisis, CSIC, Campus UAM, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Wilson
authors.forename: Andrés
authors.initials: A
authors.lastname: Illanes
authors.forename: Olga
authors.initials: O
authors.lastname: Abián
authors.forename: Benevides C C
authors.initials: BC
authors.lastname: Pessela
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernández-Lafuente
authors.forename: José M
authors.initials: JM
authors.lastname: Guisán
mesh_terms: D002384:Catalysis; D004795:Enzyme Stability; D004798:Enzymes / Q000737:chemistry*; D006868:Hydrolysis; D007477:Ions; D010399:Penicillin Amidase / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D004798:Enzymes; D007477:Ions; D011108:Polymers; D010399:Penicillin Amidase