Attachment of horseradish peroxidase (HRP) onto the poly(styrene/acrolein) latexes and onto their derivatives with amino groups on the surface; activity of immobilized enzyme

Abstract

The polystyrene (P(S)), poly(styrene/acrolein) (P(SA)), and polyacrolein (P(A)) latexes, with varied fraction of polyacrolein in the surface layer (f _A=0, 0.50, 0.63, 0.84, 1.00), were used for the attachment of horseradish peroxidase. Surfaces of latexes were modified by reaction with ethylenediamine. In this step the aldehyde groups from polyacrolein were blocked and the primary amino groups were introduced. The carbohydrate portion of HRP was oxidized in the reaction leading to formation of aldehyde groups. The adsorption and covalent immobilization of HRP onto the P(S), P(SA), and P(A) latexes and of the oxidized HRP (HRP-OX) onto the modified latex particles, with amino groups on the surface (P(SA)-M and P(A)-M), were investigated. The activities of parent and oxidized HRP were compared with activities of the corresponding enzymes in solution. It has been found that whereas HRP is not suitable for the covalent immobilization on P(SA) latex and loses its activity after adsorption onto P(S) latex, HRP-OX can be adsorbed onto P(S) latex and is readily immobilized covalently onto the ethylenediamine modified P(SA) and P(A) latexes, retaining much of its former enzymatic reactivity.