凝血酶原在肝内合成,以无生物活性的前体形式存在,经γ羧化作用转变为活性物质。γ-羧化酶需一定量的维生素 K 作为辅助因子.在维生素 K 缺乏或应用维生素 K 拮抗剂时,Glu(特异性谷氨酸)不能转变为 Gla(γ-羧基谷氨酸),而引起凝血酶原前体释放。该前体具有抗原性,但无凝血活性。此异常凝血酶原被叫做“由维生素 K 缺乏 Prothrombin is synthesized in the liver, exists as a biologically inactive precursor and is converted to an active substance by gamma-carboxylation. Gamma-carboxylase requires a certain amount of vitamin K as a cofactor, Glu (specific glutamic acid) can not be converted to Gla (γ-carboxyglutamate) in the absence of vitamin K or vitamin K antagonist, Prothrombin precursor release. The precursor is antigenic but has no clotting activity. This abnormal prothrombin is called “lack of vitamin K”