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Fluorogenic Stereochemical Probes for Transaldolases
Author(s) -
GonzálezGarcía Eva,
Helaine Virgil,
Klein Gérard,
Schuermann Melanie,
Sprenger Georg A.,
Fessner WolfDieter,
Reymond JeanLouis
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390110
Subject(s) - transaldolase , chemistry , glyceraldehyde , transketolase , diastereomer , dihydroxyacetone phosphate , stereochemistry , umbelliferone , bovine serum albumin , organic chemistry , biochemistry , enzyme , pentose phosphate pathway , dehydrogenase , coumarin , glycolysis
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.