Novel recombinant factor c and method for producing the same, and method for measuring endotoxin

Abstract

A horseshoe crab Factor C protein having activity of Factor C, wherein the horseshoe crab is selected from Tachypleus tridentatus, Limulus polyphemus, and Carcinoscorpius rotundicauda, and wherein the horseshoe crab Factor C protein is produced through being recombinantly expressed from a Chinese Hamster Ovary (CHO) DG44 cell or HEK cell.

What is claimed is: 
     
         1 . A horseshoe crab Factor C protein having activity of Factor C,
 wherein the horseshoe crab is selected from the group consisting of  Tachypleus tridentatus,  and  Limulus polyphemus,      wherein the Factor C protein is produced through being recombinantly expressed from a Chinese Hamster Ovary cell, secreted into a culture supernatant and recovered from the culture supernatant, and   wherein the Factor C protein contains (α-2,3)-linked terminal sialic acid in a greater amount, as compared with a corresponding Factor C protein recombinantly expressed using Sf9 as a host cell.   
     
     
         2 . The horseshoe crab Factor C protein according to  claim 1 , which has a molecular weight of 115 kDa to 130 kDa, as measured through SDS-PAGE under a non-reducing condition. 
     
     
         3 . An endotoxin assay kit comprising the Factor C protein according to  claim 1  and one or more elements. 
     
     
         4 . A method for measuring endotoxin in a test specimen using an endotoxin assay agent comprising the Factor C protein according to  claim 1 .