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Chromobacterium violaceum ω-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4′-substituted acetophenones, and follows Swain–Lupton parameterisation

2012; Royal Society of Chemistry; Volume: 10; Issue: 28 Linguagem: Inglês

10.1039/c2ob25893e

1477-0539

Karim Engelmark Cassimjee, Maria Svedendahl Humble, Henrik Land, Vahak Abedi, Per Berglund,

Alkaloids: synthesis and pharmacology

For biocatalytic production of pharmaceutically important chiral amines the ω-transaminase enzymes have proven useful. Engineering of these enzymes has to some extent been accomplished by rational design, but mostly by directed evolution. By use of a homology model a key point mutation in Chromobacterium violaceum ω-transaminase was found upon comparison with engineered variants from homologous enzymes. The variant Trp60Cys gave increased specificity for (S)-1-phenylethylamine (29-fold) and 4′-substituted acetophenones (∼5-fold). To further study the effect of the mutation the reaction rates were Swain–Lupton parameterised. On comparison with the wild type, reactions of the variant showed increased resonance dependence; this observation together with changed pH optimum and cofactor dependence suggests an altered reaction mechanism.