Vitamin K reaction

Vitamin K

Phytomenadione, also known as vitamin K1

Vitamin K refers to a group of fat-soluble vitamins that are essential for the synthesis of proteins required for blood coagulation and for controlling binding of calcium in bones and other tissues. The vitamin K group includes two natural vitamers: vitamin K1 and vitamin K2.

Types of Vitamin K

Vitamin K1

Vitamin K1, also known as phylloquinone or phytomenadione, is primarily found in green leafy vegetables. It is involved in photosynthesis and is the main form of vitamin K that is consumed in the diet. Vitamin K1 is directly involved in the carboxylation of certain proteins, which is essential for blood clotting.

Vitamin K2

Vitamin K2, or menaquinone, is found in animal products and fermented foods. It is produced by bacteria in the human gut and plays a role in bone metabolism and cardiovascular health. Menaquinones have a longer side chain than phylloquinone, which affects their bioavailability and function in the body.

Function

Vitamin K is crucial for the post-translational modification of certain proteins, required for blood coagulation. It acts as a cofactor for the enzyme gamma-glutamyl carboxylase, which catalyzes the carboxylation of glutamic acid residues on vitamin K-dependent proteins. This modification allows these proteins to bind calcium ions, which is necessary for their biological activity.

Deficiency

Vitamin K deficiency can lead to bleeding disorders due to impaired blood clotting. In severe cases, it can cause hemorrhagic disease of the newborn, a condition characterized by bleeding in various parts of the body. Adults with vitamin K deficiency may experience easy bruising, nosebleeds, and bleeding gums.

Sources

Dietary sources of vitamin K include green leafy vegetables such as spinach, kale, and broccoli, as well as fish, meat, and dairy products. Fermented foods like natto, a traditional Japanese dish made from fermented soybeans, are particularly high in vitamin K2.

Related pages

• Blood coagulation
• Calcium metabolism
• Fat-soluble vitamins
• Natto