Operational control of stereoselectivity during the enzymatic hydrolysis of racemic organophosphorus compounds.
The wild-type bacterial phosphotriesterase catalyzes the stereoselective hydrolysis of racemic pairs of organophosphorus compounds. The enzymatic stereoselectivity can be substantially enhanced via systematic alteration of the pKa for the leaving group phenol in the target substrates. These changes alter the rate-limiting step for substrate turnover from a diffusional event to phosphorus-oxygen bond cleavage. Turnover ratios in excess of 5000:1 were achieved using phenols with pKa values greater than 8.5. This method has enabled the isolation of the RP-enantiomer of 4-acetylphenyl methyl phenylphosphonate with an enantiomeric excess of >99% via a kinetic resolution of the racemate.
Li
Yingchun
Y
Departments of Chemistry and of Biochemistry and Biophysics, Texas A&M University, P.O. Box 30012, College Station, TX 77842-3012, USA.
Aubert
Sarah D
SD
Raushel
Frank M
FM
D043303:Aryldialkylphosphatase; D004950:Esterases / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D009943:Organophosphorus Compounds / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism
D009943:Organophosphorus Compounds; D004950:Esterases; D043303:Aryldialkylphosphatase