Vitamin K occurs naturally in two forms.
*Phylloquinone or vitamin K1 (2-methyl-3-phytyl-1,4-naphtoquinone) is synthesized by plants.
*Menaquinones or vitamin K2 (multi-isoprenyl-quinones, several species) are primarily produced by bacteria.
Bacteria synthesize a range of vitamin K forms (but not vitamin K1) using repeating isoprene (5-carbon) units in the side chain of the molecule (vide infra). These forms of vitamin K are designated menaquinone-n (MK-n), where n stands for the number of 5-carbon units in the structure. Menaquinones (MK-n) are collectively referred to as vitamin K2.
Many bacteria that populate the microbial ecosystem of the human intestine synthesize menaquinones, which they utilize as redox reagents in electron transport and oxidative phosphorylation.
Vitamin K is taken in the diet or synthesized by the intestinal bacteria. Its absorption takes place along with fat (chylomicrons) and is dependent on bile salt. Vitamin K is transported along with LDL and is stored mainly in liver and, to a lesser extent, in other tissues.
Menaquinones play important roles in electron transport, oxidative phosphorylation, active transport, and endospore formation in bacteria. In addition to these functions, the variations in the inherent structures of menaquinones and their uneven distributions among bacteria are considered important in bacterial taxonomy.
Vitamin K2 synthesized by intestinal bacteria
Nutrition is a science, a field of knowledge composed of organized facts. The study includes in areas, such as clinical nutrition, community nutrition, public health and food policy and food science. Nutrition too is a science of how the body use food. Nutrition is life. The science of nutrition helps us improve our food choices by identifying the amounts of nutrients we need, the best food sources of those nutrients, and the other components in foods that may be helpful or harmful.
Popular articles
-
Role of Sodium in Human Body The human body contains approximately 1.3 g of sodium . About a third is found in our bones. The rest is our b...
-
Nutrient Composition of Cereal Grains In composition, grains are structurally similar as seen; however, they vary in their nutrient composi...
-
Monosaccharides Monosaccharides are , as the name implies, the simplest of the carbohydrate. This classifications includes a series of alde...
-
In order to carry out its day to day physiological functions and maintain a constant body temperature (due to invariably in an environment o...
-
Water is the principle component (up to 80%) of the edible portions of seafood. Usually the oil and water content together total about 80%...