Conjugation of catalase to a carrier antibody via a streptavidin-biotin cross-linker.

Abstract

Targeting of catalase could be useful in antioxidative protection of cells challenged with H2O2. In the present study we conjugated catalase to a carrier model antibody using a biotin-streptavidin (SA) cross-linker and characterized the functional activity of the conjugate. Neither biotinylation nor conjugation with SA decreased the enzymic activity of catalase. Further coupling of radiolabelled biotinylated catalase (b-catalase) to biotinylated antibody (b-Ab) via SA using a two-step conjugation procedure did not change enzymic activity of b-catalase. b-Ab-SA-b-catalase specifically bound to antigen-coated plastic wells, but not to albumin-coated plastic wells. Substitution of b-Ab with control biotinylated IgG (b-IgG) abrogated binding of the catalase to the antigen. H2O2 was degraded in antigen-coated wells preincubated with b-Ab-SA-b-catalase, but not with b-IgG-SA-b-catalase. Thus b-Ab-SA-b-catalase specifically binds to immobilized antigen and degrades H2O2 after binding to the target. The methodology described in the present paper may be useful for the development of a novel strategy for antioxidant therapy.