These authors contributed equally to the work.
Fluorogenic Stereochemical Probes for Transaldolases
Article first published online: 11 FEB 2003
© 2002 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chemistry - A European Journal
Volume 9, Issue 4, pages 893–899, February 17, 2003
How to Cite
González-García, E., Helaine, V., Klein, G., Schuermann, M., Sprenger, G. A., Fessner, W.-D. and Reymond, J.-L. (2003), Fluorogenic Stereochemical Probes for Transaldolases. Chem. Eur. J., 9: 893–899. doi: 10.1002/chem.200390110
- Issue published online: 11 FEB 2003
- Article first published online: 11 FEB 2003
- Manuscript Received: 6 SEP 2002
- enzyme catalysis;
- enzyme evolution;
- fluorogenic assays;
- high-throughput screening
Transaldolase catalyzes the transfer of dihydroxyacetone from, for example, fructose 6-phosphate to erythrose 4-phosphate. As a potential probe for assaying fluorescent transaldolase, 6-O-coumarinyl-fructose (1) was prepared in six steps from D-fructose. The corresponding 6-O-coumarinyl-5-deoxy derivative 2 was prepared stereoselectively from acrolein and tert-butyl acetate by a chemoenzymatic route involving Amano PS lipase for the kinetic resolution of tert-butyl 3-hydroxypent-4-enoate (7) and E. coli transketolase for assembly of the final product. The corresponding stereoisomer related to D-tagatose was obtained by a chemical synthesis starting from D-ribose. Indeed, transaldolases catalyze the retro-aldolization of substrate 1 to give dihydroxyacetone and 3-O-coumarinyl-glyceraldehyde. The latter primary product undergoes a β-elimination in the presence of bovine serum albumin (BSA) to give the strongly fluorescent product umbelliferone. A similar reaction is obtained with the 5-deoxy analogue 2, but there is almost no reaction with its stereoisomer 3. The stereoselectivity of transaldolases can be readily measured by the relative rates of fluorescence development in the presence of the latter pair of diastereomeric substrates.