Method for producing an exdotoxin measuring agent

A method for producing an endotoxin measuring agent, the method comprising:

• (A) incorporating each of the DNAs (1) to (3) below into a baculovirus:
• (1) a DNA encoding a factor C, wherein the factor C is a protein described as (A′) or (B′) below, and does not have His-tag sequence or any peptide attached at the C-terminus:
• (A′) a protein consisting of the amino acid sequence shown in SEQ ID NO:
• 2;
• (B′) a protein consisting of an amino acid sequence having not less than 90% sequence identity compared to the full-length amino acid sequence shown in SEQ ID NO:2, wherein the protein has factor C activity;
• (2) a DNA encoding a factor B of a horseshoe crab;
• and
• (3) a DNA encoding a proclotting enzyme of a horseshoe crab;
• (B) infecting insect cells with the baculovirus;
• (C) allowing the insect cells infected with the baculovirus to express the factor C, the factor B and the proclotting enzyme;
• (D) recovering factor C, factor B, and proclotting enzyme, which are expressed from the insect cells into a culture supernatant;
• (E) eliminating the baculovirus from the expressed factor C, the expressed factor B, and the expressed proclotting enzyme;
• and
• (F) formulating the endotoxin measuring agent comprising the expressed factor C, the expressed factor B, and the expressed proclotting enzyme from which the baculovirus was eliminated.