Vitamin K – Phylloquinone

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Occurrence and structure

Vitamin K is produced by plants and by our intestinal bacteria. An important structural feature is naphthoquinone (consisting of 2 rings), to which a side chain is attached. Vitamin K plays an important role in blood clotting.

It modifies the coagulation factors II, VII, IX and X, as well as the coagulation inhibitors Protein C and Protein S. Vitamin K carboxylates (attaches a COOH group) these factors, which thereby receive a negative charge. This negative charge enables the clotting factors and inhibitors to bind a positively charged calcium ion. This “complex” of coagulation factor and calcium in turn can now dock to the negatively charged outer surface of cell membranes – only in the case of tissue damage.

In this way, the coagulation factors can remain in one place and are not washed away with the blood flow from the place where they are needed. In everyday clinical practice, so-called vitamin K antagonists (i.e. opponents of vitamin K) are used to inhibit clotting. For example, in patients after a heart attack to prevent the formation of a new dangerous blood clot.

These inhibitors prevent vitamin K from carboxylating its above-mentioned substrates. Thus they lose their function and clotting is inhibited. Up to the beginning of effect however 2-3 days pass, since only once still another “pool” at coagulation factors already carboxylated by Vitamin K is present. An example of a vitamin K antagonist is the drug Marcumar. For interested: Under treatment with vitamin K – antagonists the Quick value is increased, the bleeding time of the extrinsic coagulation system thus extended.

Symptoms of deficiency

A lack of Vitamin K is extremely rare, since it is also produced by intestinal bacteria. Such a lack can have dangerous effects however with newborn children, whose Darmflora inclusive bacteria is not yet so far developed that here sufficient Vitamin K is produced. A lack leads to strong bleeding tendency.

Understandably, since the factors, which cause a fast stopping of a possible bleeding with the help of the modification of Vitamin K, are no longer functional, if the body Vitamin K is missing. Even small injuries (microtraumas) can lead to bleeding that has been going on for a long time (constant nosebleeds, many bruises). Vitamin K occurs in 2 natural forms: Vitamin K1 and vitamin K2. Vitamin K2 helps to give the bones greater stability and reduces the number of fractures. Water-soluble (hydrophilic) vitamins: Fat-soluble (hydrophobic) vitamins:

  • Vitamin B1 – thiamine
  • Vitamin B2 – Riboflavin
  • Vitamin B3 – Niacin
  • Vitamin B5 – pantothenic acid
  • Vitamin B6 – PyridoxalPyridoxinPyridoxamine
  • Vitamin B7 – biotin
  • Vitamin B9 – folic acid
  • Vitamin B12 – cobalamin
  • Vitamin A – Retinol
  • Vitamin C – Ascorbic acid
  • Vitamin D – Calcitriol
  • Vitamin E – tocopherol
  • Vitamin K – PhylloquinoneMenachinone