title: Improved stabilization of chemically aminated enzymes via multipoint covalent attachment on glyoxyl supports.
abstract: The surface carboxylic groups of penicillin G acylase and glutaryl acylase were chemically aminated in a controlled way by reaction with ethylenediamine via the 1-ethyl-3-(dimethylamino-propyl) carbodiimide coupling method. Then, both proteins were immobilized on glyoxyl agarose. In both cases, the immobilization of the chemically modified enzymes improved the enzyme stability compared to the stability of the immobilized but non-modified enzyme (by a four-fold factor in the case of PGA and a 20-fold factor in the case of GA). The chemical modification presented a deleterious effect on soluble enzyme stability. Therefore, the improved stability should be related to a higher multipoint covalent attachment, involving both the lysine amino groups and also the new amino groups chemically introduced on the enzyme. Moreover, the lower pK(a) of the new amino groups permitted to immobilize the enzyme under milder conditions. In fact, the aminated proteins could be immobilized even at pH 9, while the non-modified enzymes could only be immobilized at pH over 10.
authors.affiliation: Departamento de Biocatálisis, Instituto de Catálisis, CSIC, Campus Universidad Autonoma, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: López-Gallego
authors.forename: Tamara
authors.initials: T
authors.lastname: Montes
authors.forename: Manuel
authors.initials: M
authors.lastname: Fuentes
authors.forename: Noelia
authors.initials: N
authors.lastname: Alonso
authors.forename: Valeria
authors.initials: V
authors.lastname: Grazu
authors.forename: Lorena
authors.initials: L
authors.lastname: Betancor
authors.forename: Jose M
authors.initials: JM
authors.lastname: Guisán
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernández-Lafuente
mesh_terms: D000588:Amines / Q000737:chemistry*; D004798:Enzymes / Q000737:chemistry*; D006037:Glyoxal / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration
chemical_list: D000588:Amines; D004798:Enzymes; D006037:Glyoxal