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This article provides a method to upgrade epoxy-functionalized carriers for covalent enzyme immobilization to selective carriers suitable for covalent immobilization of metal affinity-tagged enzymes without the need of preliminary enzyme purification. Affinity function doping of the epoxy-functionalized surface introduces an advanced possibility to avoid the costly and time-consuming downstream processes required for efficient immobilization on non-selective epoxy carriers. Our approach is based on the partial functionalization of surface epoxides via a proper diamine-derived linker and an ethylenediaminetetraacetic dianhydride-based chelator charged with cobalt ions. The solid macroporous carriers, doped with metal affinity functions, have both coordinative binding ability (rapid anchoring the metal affinity-tagged enzymes to the surface) and subsequent covalent bond-forming ability (preferred binding of the tagged enzyme to the surface after proper washing by the residual epoxide functions), enabling a single operation for the enrichment and immobilization of a recombinant phenylalanine ammonia-lyase from parsley fused to a polyhistidine affinity tag. The immobilized PcPAL was applied in the ammonia elimination of racemic phenylalanine, 4-chlorophenylalanine, and 4-bromophenylalanine to produce the corresponding d-phenylalanines, in addition to the formation of (E)-cinnamates, as well as in ammonia addition reactions to (E)-cinnamates, yielding the corresponding enantiopure l-phenylalanines. [ABSTRACT FROM AUTHOR]

Immobilized metal ion affinity chromatography principles were applied for selective immobilization of recombinant polyhistidine tag fused phenylalanine ammonia-lyase from parsley (PcPAL) on porous polymeric support with aminoalkyl moieties modified with an EDTA dianhydride (EDTADa)-derived chelator and charged with transition metal ions. Out of the five investigated metal ions - Fe3+, Co2+, Ni2+, Cu2+, Zn2+ - the best biocatalytic activity of PcPAL was achieved when the enzyme was immobilized on the Co2+ ion-charged support (31.8 ± 1.2 U/g). To explore the features this PcPAL obtained by selective immobilization, the thermostability and reusability of this PAL biocatalyst were investigated. To maximize the activity of the immobilized PcPAL the surface functionalization of the aminoalkylated polymeric carrier was fine-tuned with using glycidol as a thinning group beside EDTADa. The maximal activity yield (YA=103 %) was earned when the EDTADa and glycidol were used in 1 to 24 ratio. The reversibility of the immobilization method allowed the development of a support regeneration protocol which enables easy reuse of the functionalized support in case of enzyme inactivation. [ABSTRACT FROM AUTHOR]