[In vivo metabolism of vitamin K: in relation to the conversion of vitamin K1 to MK-4]

Clin Calcium. 2009 Dec;19(12):1779-87.
[Article in Japanese]


Phylloquinone is a major form (>90%) of dietary vitamin K, but the form of vitamin K that exists at the highest concentrations in tissues of animals and humans is menaquinone-4 (MK-4) . Despite this great difference, the origin of tissue MK-4 had not been clarified until recently. We demonstrated that deuterium-labeled phylloquinone was converted into deuterium-labeled MK-4 in mice and this conversion occurred following an oral or enteral administration, but not parenteral administration. By the oral route, the phylloquinone with the deuterium-labeled side chain (phytyl side-chain) was clearly converted into menaquinone-4 with a non-deuterium-labeled side chain (geranylgeranyl side-chain), implying that phylloquinone was converted into menaquinone-4 via integral side-chain removal. Our results suggest that cerebral menaquinone-4 originates from phylloquinone intake and the release of menadione from phylloquinone in the intestine followed by the prenylation of menadione into menaquinone-4 in the intestine or tissues.

Publication types

  • Review

MeSH terms

  • Administration, Oral
  • Animals
  • Brain / metabolism
  • Humans
  • Intestinal Absorption
  • Intestinal Mucosa / metabolism
  • Mice
  • Neurons / metabolism
  • Tissue Distribution
  • Vitamin K 1 / administration & dosage*
  • Vitamin K 1 / chemistry
  • Vitamin K 1 / metabolism*
  • Vitamin K 2 / analogs & derivatives*
  • Vitamin K 2 / metabolism


  • Vitamin K 2
  • menatetrenone
  • Vitamin K 1