Methods and compositions for producing active vitamin K-dependent proteins

A method of increasing the amount of carboxylated vitamin K dependent protein in a mammalian cell, comprising introducing, into a mammalian cell that expresses a first nucleic acid encoding a vitamin K dependent protein, a second nucleic acid comprising a heterologous nucleotide sequence encoding vitamin K epoxide reductase (VKOR), wherein the heterologous nucleotide sequence encoding VKOR is a nucleotide sequence that encodes a Nematostella VKOR, under conditions whereby said first and second nucleic acids are expressed to produce a vitamin K dependent protein and VKOR, respectively, thereby increasing the amount of carboxylated vitamin K dependent protein in the mammalian cell.