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Life Sci. 2005 Apr 8;76(21):2473-82.

Vitamin K2 binds 17beta-hydroxysteroid dehydrogenase 4 and modulates estrogen metabolism.

Author information

1
Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. motoootsuka-gi@umin.ac.jp

Abstract

Vitamin K is a cofactor for gamma-glutamyl carboxylase, an enzyme that is important for blood coagulation. Recent studies have shown that vitamin K has other roles, in addition to post-transcriptional modification, such as bone metabolism and antitumoral actions; these findings have indicated that there might be unknown intracellular binding proteins that are specific for vitamin K. In this study, vitamin K-binding proteins were characterized by pull-down experiment using a chemically synthesized biotynylated vitamin K followed by mass spectrometric identification of the pull-downed components. The results indicated that 17beta hydroxy steroid dehydrogenase 4, apolipoportein E, and 40S ribosomal proteins S7 and S13 might be the candidates of the vitamin K-binding proteins. Subsequent experiments showed that vitamin K2 binds 17beta hydroxysteroid dehydrogenase 4 and decreases the intracellular estradiol:estrone ratio, which resulted in the inhibition of the amount of estrogen receptor alpha-binding to its target DNA. These results suggest a possible novel role for vitamin K in modulating estrogen function.

PMID:
15763078
DOI:
10.1016/j.lfs.2004.12.020
[Indexed for MEDLINE]

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