ABSTRACT
The vitamin K-dependent proteins are characterized by (1) their dependence on vitamin K for the synthesis of a mature, functional protein and (2) the presence of γ-carboxyglutamic acid (GLA) in the amino-terminal portion of the mature protein. The vitamin K-dependent proteins, with the exception of prothrombin, are modest, globular proteins with molecular weights between 50 and 70 kDa and are present in the plasma at low concentrations. A list of the characterized vitamin Kdependent proteins of biotechnological interest is presented in Table 8.1. In addition to the plasma proteins, γ-carboxylation occurs in the proteins found in the bones and cartilage.1-3 There has been recent interest in the role of Vitamin K in hard tissue function4-7 with an emphasis on osteoporosis,8,9 which may be associated with γ-carboxylation.9 As Vermeer and Theuwissen note, inadequate dietary Vitamin K is a modi€able risk factor for osteoporosis.
