Post-transcriptional maturation with the presence of vitamin K(2) promotes gamma-carboxylation of osteocalcin, enabling further binding to hydroxyapatite, from which one could infer that vitamin K(2) increased the quality of bone matrix. For instance, vitamin K(2) rescued the impaired collagen mineralization caused by Mg insufficiency, by promoting a re-association of the process of collagen mineralization with mineralized nodules. Sodium warfarin, which antagonizes the function of vitamin K(2), reduced the binding of osteocalcin to bone matrices, and consequently resulted in crystalline particles being dispersed throughout the osteoid without forming mineralized nodules. Therefore, gamma-carboxylated Gla proteins mediated by vitamin K(2) appear to play a pivotal role in normal mineralization in bone.