Limulus clotting enzyme explained

Limulus clotting enzyme
Ec Number:	3.4.21.86

Limulus clotting enzyme (clotting enzyme) is an enzyme.^{[1] [2]} This enzyme catalyses the following chemical reaction:

Selective cleavage of -Arg¹⁸- and -Arg⁴⁷- bonds in coagulogen to form coagulin and fragments

This enzyme is present in the hemocyte granules of horseshoe crabs Limulus and Tachypleus. In the immunity-related clotting pathways of these organisms, it is the final enzyme responsible for the activation of coagulin.^[3]

Notes and References

1. Muta T, Hashimoto R, Miyata T, Nishimura H, Toh Y, Iwanaga S . Proclotting enzyme from horseshoe crab hemocytes. cDNA cloning, disulfide locations, and subcellular localization . The Journal of Biological Chemistry . 265 . 36 . 22426–33 . December 1990 . 10.1016/S0021-9258(18)45722-5 . 2266134 . free .
2. Tokunaga F, Nakajima H, Iwanaga S . Further studies on lipopolysaccharide-sensitive serine protease zymogen (factor C): its isolation from Limulus polyphemus hemocytes and identification as an intracellular zymogen activated by alpha-chymotrypsin, not by trypsin . Journal of Biochemistry . 109 . 1 . 150–7 . January 1991 . 10.1093/oxfordjournals.jbchem.a123337 . 2016264 .
3. Iwanaga . S . Biochemical principle of Limulus test for detecting bacterial endotoxins. . Proceedings of the Japan Academy. Series B, Physical and Biological Sciences . May 2007 . 83 . 4 . 110–9 . 10.2183/pjab.83.110 . 24019589 . 3756735. 2007PJAB...83..110I .