Simon Waltzer

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The intermolecular asymmetric Stetter reaction is a rarely found biocatalysts transformation. MenD, the second enzyme of the menaquinone biosynthetic pathway, catalyzes as a physiological reaction a Stetter-like addition of α-ketoglutarate to isochorismate. The substrate range of MenD for similar 1,4-additions is highly restricted. All other thiamine(More)
Asymmetric mixed carboligation reactions of α-ketoglutarate with different aldehydes were explored with the thiamine diphosphate dependent enzymes SucA from E. coli, Kgd from Mycobacterium tuberculosis, and MenD from E. coli. All three enzymes proved to be efficient biocatalysts to selectively deliver chiral δ-hydroxy-γ-keto acids with moderate to excellent(More)
The thiamine diphosphate (ThDP)-dependent enzyme cyclohexane-1,2-dione hydrolase (CDH) was expressed in Escherichia coli and purified by affinity chromatography (Ni-NTA). Recombinant CDH showed the same C-C bond-cleavage and C-C bond-formation activities as the native enzyme. Furthermore, we have shown that CDH catalyzes the asymmetric cross-benzoin(More)
We report the first rationally designed (S)-selective MenD from E. coli for the synthesis of functionalized α-hydroxy ketones. By mutation of two amino acids in the active site stereoselectivity of the (R)-selective EcMenD (ee > 93%) was inverted giving access to (S)-5-hydroxy-4-oxo-5-phenylpentanoate derivatives with stereoselectivities up to 97% ee.
The catalytic asymmetric synthesis of chiral 2-hydroxy ketones by using different thiamine diphosphate dependent enzymes, namely benzaldehyde lyase from Pseudomonas fluorescens (PfBAL), a variant of benzoylformate decarboxylase from Pseudomonas putida (PpBFD-L461A), branched-chain 2-keto acid decarboxylase from Lactococcus lactis (LlKdcA) and a variant of(More)
ThDP-dependent cyclohexane-1,2-dione hydrolase (CDH) catalyzes the CC bond cleavage of cyclohexane-1,2-dione to 6-oxohexanoate, and the asymmetric benzoin condensation between benzaldehyde and pyruvate. One of the two reactivities of CDH was selectively knocked down by mutation experiments. CDH-H28A is much less able to catalyze the CC bond formation,(More)
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