Sterol 3ß-glucosyltransferase biocatalysts with a range of selectivities, including selectivity for testosterone.

The main objectives of this work were to characterise a range of purified recombinant sterol 3ß-glucosyltransferases and show that rational sampling of the diversity that exists within sterol 3ß-glucosyltransferase sequence space can result in a range of enzyme selectivities. In our study the catalytically active domain of the Saccharomyces cerevisiae 3ß-glucosyltransferase was used to mine putative sterol 3ß-glucosyltransferases from the databases. Selected diverse sequences were expressed in and purified from Escherichia coli and shown to have different selectivities for the 3ß-hydroxysteroids ergosterol and cholesterol. Surprisingly, three enzymes were also selective for testosterone, a 17ß-hydroxysteroid. This study therefore reports for the first time sterol 3ß-glucosyltransferases with selectivity for both 3ß- and 17ß-hydroxysteroids and is also the first report of recombinant 3ß-glucosyltransferases with selectivity for steroids with a hydroxyl group at positions other than C-3. These enzymes could therefore find utility in the pharmaceutical industry for the green synthesis of a range of glycosylated compounds of medicinal interest.

Synthesis of enantiomerically pure isotopomers of 2-phenylpropionic acids.

A series of enantiomerically pure [D,(13)C]-labeled isotopomeric 2-phenylpropionic acids were efficiently synthesized using a diastereoselective alkylation and kinetic resolution strategy.

Parallel kinetic resolution of an oxazolidinone using a quasi-enantiomeric combination of [D,13C]-isotopomers of pentafluorophenyl 2-phenyl propionate.

Parallel kinetic resolution of Evans' phenylglycine derived oxazolidinone using an equimolar combination of quasi-enantiomeric active esters (derived from [D,13C]-labeled 2-phenylpropionic acid) was achieved. The levels of stereocontrol were high, leading to products with predictable configurations.

Mutual kinetic separation of isotopomers of pentafluorophenyl 2-phenyl propionate using quasi-enantiomeric oxazolidinones.

Mutual separation of an equimolar mixture of quasi-enantiomeric [D,13C]-labeled isotopomers of pentafluorophenyl 2-phenylpropionate can be achieved efficiently by use of two quasi-enantiomeric Evans' oxazolidinones. The levels of stereocontrol were high, leading to products with predictable configurations.