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Characterization of mammalian sedoheptulokinase and mechanism of formation of erythritol in sedoheptulokinase deficiency
Author(s) -
Kardon Tamas,
Stroobant Vincent,
Veiga-da-Cunha Maria,
Schaftingen Emile Van
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.08.024
Subject(s) - mechanism (biology) , erythritol , chemistry , characterization (materials science) , microbiology and biotechnology , biochemistry , biology , materials science , nanotechnology , philosophy , epistemology
Our aim was to identify the product formed by sedoheptulokinase and to understand the mechanism of formation of erythritol in patients with sedoheptulokinase deficiency. Mouse recombinant sedoheptulokinase was found to be virtually specific for sedoheptulose and its reaction product was identified as sedoheptulose 7‐phosphate. Assays of sedoheptulose in plant extracts disclosed that this sugar is present in carrots (≈7 μmol/g) and in several fruits. Sedoheptulose 1‐phosphate is shown to be a substrate for aldolase B, which cleaves it to dihydroxyacetone‐phosphate and erythrose. This suggests that, in patients deficient in sedoheptulose‐7‐kinase, sedoheptulose is phosphorylated by fructokinase to sedoheptulose 1‐phosphate. Cleavage of the latter by aldolase B would lead to the formation of erythrose, which would then be reduced to erythritol.