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Albrecht Berkessel, Magali Dousset, Stephan Bulat, Katja Glaubitz

Combinatorial approaches to functional models for galactose oxidase

Keywords: combinatorial chemistry, copper complexes, galactose oxidase, peptide libraries, Schiff-base ligands

The copper enzyme galactose oxidase (GOase, EC 1.1.3.9) catalyses the oxidation of D-galactose and other primary alcohols in air to the corresponding aldehydes and hydrogen peroxide. The current mechanistic hypothesis for this two-electron redox reaction involves a Cu(I)/Cu(II) couple and the reversible oxidation of a ligating phenolate (tyrosine residue of the Tyr₂₇₂-Cys₂₂₈ conjugate) to a phenoxyl radical. Our approaches to functional models for galactose oxidase comprise both the use of low-molecular-weight copper complexes of a Schiff-base and sulfonamide ligands, and the synthesis/screening of combinatorial libraries. With regard to the latter, we have synthesized (by the IRORI-directed synthesis approach) peptide libraries carrying either His or the redox-active amino acids Tyr, mod-Cys (a model for the Tyr₂₇₂-Cys₂₂₈ conjugate) or TOAC (a TEMPO-derived ?-amino acid) at four variable positions. After incubation with copper ions, the catalytically active library members were identified by specially designed screening methods.

Biological Chemistry, Walter de Gruyter

Print ISSN: 1431-6730
Volume: 386, 10/2005
Pages: 1035 - 1041

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