The human pyridoxal kinase, a plausible target for ginkgotoxin from Ginkgo biloba.

Full Abstract

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.

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Author information

Author/s: Kästner, Uta (U); Hallmen, Christian (C); Wiese, Michael (M); Leistner, Eckhard (E); Drewke, Christel (C);

Affiliation: Institut für Pharmazeutische Biologie, Universität Bonn, Germany.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The FEBS journal (FEBS J), published in England. (Language: eng)

Reference: 2007-Feb; vol 274 (issue 4) : pp 1036-45

Dates: Created 2007/02/02; Completed 2007/04/24;

PMID: 17250738, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Binding Sites
Enzyme Inhibitors - chemistry; metabolism
Ginkgo biloba - chemistry
Humans
Kinetics
Models, Molecular
Plant Extracts - chemistry
Plants, Medicinal - chemistry

Plants, Medicinal - chemistry
Pyridoxal Kinase - isolation & purification; metabolism
Pyridoxal Phosphate - metabolism
Pyridoxine - analogs & derivatives; chemistry; metabolism
Recombinant Proteins - isolation & purification; metabolism
Time Factors
Vitamin B 6 - chemistry; metabolism
Vitamin B Complex - chemistry; metabolism

Associated Chemicals: 4'-O-methylpyridoxine (0) ; Enzyme Inhibitors (0) ; Plant Extracts (0) ; Recombinant Proteins (0) ; Vitamin B Complex (12001-76-2) ; Pyridoxal Phosphate (54-47-7) ; Pyridoxine (65-23-6) ; Vitamin B 6 (8059-24-3) ; Pyridoxal Kinase (EC 2.7.1.35)

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