Pyruvate aldolases in chiral carbon-carbon bond formation.
A procedure for the preparation of optically pure alpha-keto-gamma-hydroxy carboxylic acids through stereospecific aldol addition catalyzed by pyruvate aldolases from the Entner-Doudoroff and the DeLey-Doudoroff glycolytic pathways is described. This highly versatile fragment serves as a precursor for a variety of commonly encountered functionalities, including beta-hydroxy aldehydes and carboxylic acids, alpha-amino-gamma-hydroxy carboxylic acids and alpha,gamma-dihydroxy carboxylic acids. The protocol described here uses recombinant His6-tagged KDPG aldolase for the synthesis of (S)-4-hydroxy-2-keto-4-(2'-pyridyl)butyrate. A protocol for evaluating enantiomeric excess through formation of the gamma-lactone of the dithioacetal followed by chiral-phase gas-liquid chromatography is also described. Enzyme expression and enzymatic synthesis can be accomplished in approximately 1 week. The enzymatic aldol addition proceeds in nearly quantitative yields with enantiomeric excesses greater than 99.7%.
Walters
Matthew J
MJ
Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
Toone
Eric J
EJ
D000446:Aldehyde-Lyases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002244:Carbon; D002264:Carboxylic Acids / Q000737:chemistry / Q000378:metabolism; D007202:Indicators and Reagents; D007783:Lactones / Q000737:chemistry; D010957:Plasmids; D011773:Pyruvates / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry
D002264:Carboxylic Acids; D007202:Indicators and Reagents; D007783:Lactones; D011773:Pyruvates; D011994:Recombinant Proteins; D002244:Carbon; D000446:Aldehyde-Lyases; C100131:phospho-2-keto-3-deoxy-gluconate aldolase