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The human pyridoxal kinase, a plausible target for ginkgotoxin from Ginkgo biloba
Author(s) -
Kästner Uta,
Hallmen Christian,
Wiese Michael,
Leistner Eckhard,
Drewke Christel
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.05654.x
Subject(s) - ginkgo biloba , pyridoxamine , pyridoxal , pyridoxine , ginkgo , biochemistry , enzyme , chemistry , in vivo , pyridoxal phosphate , in vitro , homogeneous , pharmacology , medicine , biology , traditional medicine , microbiology and biotechnology , cofactor , physics , thermodynamics
Ginkgotoxin (4′‐ O ‐methylpyridoxine) occurring in the seeds and leaves of Ginkgo biloba , is an antivitamin structurally related to vitamin B 6 . Ingestion of ginkgotoxin triggers epileptic convulsions and other neuronal symptoms. Here we report on studies on the impact of B 6 antivitamins including ginkgotoxin on recombinant homogeneous human pyridoxal kinase (EC 2.7.1.35). It is shown that ginkgotoxin serves as an alternate substrate for this enzyme with a lower K m value than pyridoxal, pyridoxamine or pyridoxine. Thus, the presence of ginkgotoxin leads to temporarily reduced pyridoxal phosphate formation in vitro and possibly also in vivo . Our observations are discussed in light of Ginkgo medications used as nootropics.