Investigation of the Cosolvent Effect on Six Isoenzymes of PLE in the Enantioselective Hydrolysis of Selected α,α‐Disubstituted Malonate Esters

Smith, Maureen E.; Banerjee, Souvik; Shi, Yongliang; Schmidt, Marlen; Bornscheuer, Uwe T.; Masterson, Douglas S.

doi:10.1002/cctc.201100490

Cited by 24 publications

(22 citation statements)

References 28 publications

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“…The other isoenzymes (PLE 2-6) all produced similar yields of approximately 60%. The enantioselectivity for these hydrolysis reactions is consistent with previously reported data [38]. Crude PLE, PLE 1, and PLE 2 all produced predominantly the (R)-enantiomer, whereas PLE 3, PLE 4, PLE 5, and PLE 6 all produced predominantly the (S)-enantiomer.…”

Section: Results Of Mass Spectrometry Assaysupporting

confidence: 90%

“…Previously, cosolvent studies were conducted with this substrate and PLE isoenzymes [38]. However, using the previous assay, only enantioselectivity data was obtained and data regarding yield of the reactions was not available.…”

Section: Results Of Mass Spectrometry Assaymentioning

confidence: 99%

“…In this assay, the ethyl acid-ester molecule (6) was used as the standard whereas the methyl acid-ester (3) was the analyte. Additionally, from previous work, the diethyl ester provided moderate enantioselectivities with some of the isoenzymes, and we were interested to see how the methyl diester compared [38]. The yields and enantioselectivities of the hydrolysis reactions of 9 are displayed in Table 1.…”

Section: Results Of Mass Spectrometry Assaymentioning

confidence: 99%

“…PLE 3 and PLE 4 provided poor enantioselectivity. However, it is known that the diethyl ester provides poor enantioselectivity upon hydrolysis with crude PLE [38].…”

Section: Results Of Mass Spectrometry Assaymentioning

confidence: 99%

“…The preparation of the methyl diesters, half esters, and probes were prepared according to modified literature procedures, using dimethyl methyl malonate in place of diethyl methyl malonate [16,[38][39][40]. Full synthetic detail is provided in the Supporting Information [ESM1].…”

Section: Synthesis Of Probes and Standard Moleculesmentioning

confidence: 99%

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An ESI-MS Method to Determine Yield and Enantioselectivity in a Single Assay

Smith

Knolls

Thompson

et al. 2014

J. Am. Soc. Mass Spectrom.

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Abstract. A mass spectrometry assay is presented here that allows for the simultaneous determination of yield and enantioselectivity in a single analysis. The assay makes use of molecules that are structurally similar to the analytes of interest as standards. The assay predicts the yields of the reactions reasonably well and with little error. For example, in the pig liver esterase catalyzed hydrolysis of one prochiral malonate, the yield predicted by the assay was 72%, while larger scale isolated reaction yields were within 5% of this value. This assay provides a fast method to determine yield and enantioselectivity in one analysis. The strengths and limitations of this method are discussed.

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Section: Results Of Mass Spectrometry Assaysupporting

confidence: 90%

Section: Results Of Mass Spectrometry Assaymentioning

confidence: 99%

Section: Results Of Mass Spectrometry Assaymentioning

confidence: 99%

“…PLE 3 and PLE 4 provided poor enantioselectivity. However, it is known that the diethyl ester provides poor enantioselectivity upon hydrolysis with crude PLE [38].…”

Section: Results Of Mass Spectrometry Assaymentioning

confidence: 99%

Section: Synthesis Of Probes and Standard Moleculesmentioning

confidence: 99%

See 3 more Smart Citations

An ESI-MS Method to Determine Yield and Enantioselectivity in a Single Assay

Smith

Knolls

Thompson

et al. 2014

J. Am. Soc. Mass Spectrom.

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Two Subtle Amino Acid Changes in a Transaminase Substantially Enhance or Invert Enantiopreference in Cascade Syntheses

Skalden¹,

Peters²,

Dickerhoff³

et al. 2015

ChemBioChem

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Amine transaminases (ATAs) are powerful enzymes for the stereospecific production of chiral amines. However, the synthesis of amines incorporating more than one stereocenter is still a challenge. We developed a cascade synthesis to access optically active 3-alkyl-substituted chiral amines by combining two asymmetric synthesis steps catalyzed by an enoate reductase and ATAs. The ATA wild type from Vibrio fluvialis showed only modest enantioselectivity (14 % de) in the amination of (S)-3-methylcyclohexanone, the product of the enoate-reductase-catalyzed reaction step. However, by protein engineering we created two variants with substantially improved diastereoselectivities: variant Leu56Val exhibited a higher R selectivity (66 % de) whereas the Leu56Ile substitution caused a switch in enantiopreference to furnish the S-configured diastereomer (70 % de). Addition of 30 % DMSO further improved the selectivity and facilitated the synthesis of (1R,3S)-1-amino-3-methylcyclohexane with 89 % de at 87 % conversion.

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An Investigation of the Interaction of Co‐Solvent with Substrates in the Pig Liver Esterase‐Catalyzed Hydrolysis of Malonate Esters

et al. 2015

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Previously, we have reported the effect of several co‐solvents, including ethanol, on the enantioselective outcome of pig liver esterase (PLE) hydrolysis reactions. The greatest improvements were observed in those substrates that contained an atom capable of forming a hydrogen bond in the sidechain portion of the molecule. To further explore the interaction between substrate and ethanol, a second series of substrates were synthesized, in which the hydrogen bonding atoms of the side chain were modified, and subjected to PLE hydrolysis. Substrates containing atoms capable of forming hydrogen bonds showed the largest equilibrium constants. However, a large equilibrium constant did not always produce significant changes in enantioselectivity as hypothesized. Finally, molecular modeling experiments were performed to obtain a better understanding of the interactions. These experiments revealed that there are substrate–enzyme interactions that can be influenced by the addition of ethanol.

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Investigation of the Cosolvent Effect on Six Isoenzymes of PLE in the Enantioselective Hydrolysis of Selected α,α‐Disubstituted Malonate Esters

Cited by 24 publications

References 28 publications

An ESI-MS Method to Determine Yield and Enantioselectivity in a Single Assay

An ESI-MS Method to Determine Yield and Enantioselectivity in a Single Assay

Two Subtle Amino Acid Changes in a Transaminase Substantially Enhance or Invert Enantiopreference in Cascade Syntheses

An Investigation of the Interaction of Co‐Solvent with Substrates in the Pig Liver Esterase‐Catalyzed Hydrolysis of Malonate Esters

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