TCA Cycle Involved Enzymes SucA and Kgd, as well as MenD: Efficient Biocatalysts for Asymmetric C–C Bond Formation
作者:Maryam Beigi、Simon Waltzer、Alexander Fries、Lothar Eggeling、Georg A. Sprenger、Michael Müller
DOI:10.1021/ol3031186
日期:2013.2.1
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 stereoselectivity. The high regioselectivity
BALDWIN, JACK E.;ADLINGTON, ROBERT M.;RUSSELL, MARK A.;SCHOFIELD, CHRISTO+, J. LABELL. COMPOUNDS AND RADIOPHARM., 27,(1989) N, C. 1091-1099
作者:BALDWIN, JACK E.、ADLINGTON, ROBERT M.、RUSSELL, MARK A.、SCHOFIELD, CHRISTO+
DOI:——
日期:——
α-Hydroxy-β-keto acid rearrangement–decarboxylation: impact on thiamine diphosphate-dependent enzymatic transformations
作者:Maryam Beigi、Sabrina Loschonsky、Patrizia Lehwald、Volker Brecht、Susana L. A. Andrade、Finian J. Leeper、Werner Hummel、Michael Müller
DOI:10.1039/c2ob26981c
日期:——
The thiamine diphosphate (ThDP) dependent MenD catalyzes the reaction of α-ketoglutarate with pyruvate to selectively form 4-hydroxy-5-oxohexanoic acid 2, which seems to be inconsistent with the assumed acyl donor role of the physiological substrate α-KG. In contrast the reaction of α-ketoglutarate with acetaldehyde gives exclusively the expected 5-hydroxy-4-oxo regioisomer 1. These reactions were studied by NMR and CD spectroscopy, which revealed that with pyruvate the observed regioselectivity is due to the rearrangementâdecarboxylation of the initially formed α-hydroxy-β-keto acid rather than a donorâacceptor substrate role variation. Further experiments with other ThDP-dependent enzymes, YerE, SucA, and CDH, verified that this degenerate decarboxylation can be linked to the reduced enantioselectivity of acyloins often observed in ThDP-dependent enzymatic transformations.