Vitamin K and Bone
One of the important functions on which the last 40 years investigating the relationship between plasma concentration of vitamin K and osteocalcin. Osteocalcin is a protein produced by osteoblasts or bone cells, is directly dependent on vitamin K. Osteoblasts synthesize bone tissue and are involved in the development and growth of bones and mineralization. Osteocalcin is directly involved in bone mineralization, since it is necessary to effectively join the calcium with bone matrix.
Vitamin K2 (the active form of vitamin K synthesized by intestinal bacteria) is a cofactor for the carboxylase, an enzyme essential for converting glutamic acid gamma-carboxyglutamic acid (Gla). This molecule is part of osteocalcin, also called  “bone Gla protein” by the presence in the composition of three residues of gamma-carboxyglutamic acid (Gla). The Gla is common to all proteins dependent on vitamin K, and increases the affinity of these proteins for calcium. For this reason, osteocalcin is considered as a factor in bone health.
It appears that osteocalcin regulates the growth of crystals of hydroxyapatite (tricalcium phosphate), the majority of bone minerals. Together with other salts such as calcium carbonate, sulfate, fluoride and magnesium hydroxide, are the inorganic components of bone matrix, whose main component is collagen. The minerals are deposited and crystallized in the lattice of collagen, tightening the bone and making it flexible and resilient at the same time.