Limulus clotting factor C

Limulus clotting factor overbar C (EC 3.4.21.84, factor C, limulus factor C) is an enzyme.[1][2][3] This enzyme catalyses the following chemical reaction

Limulus clotting factor overbar C
Identifiers
EC no.3.4.21.84
CAS no.115743-27-6
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
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PDB structuresRCSB PDB PDBe PDBsum
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NCBIproteins
Limulus clotting factor C
Identifiers
OrganismTachypleus tridentatus
Symbol?
UniProtP28175
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StructuresSwiss-model
DomainsInterPro
Selective cleavage of -Arg103-Ser- and -Ile124-Ile- bonds in limulus clotting factor B to form factor overbar B.
Cleavage of -Pro-Arg- bonds in synthetic substrates

This enzyme is isolated from the hemocyte granules of the horseshoe crabs Limulus and Tachypleus, where it serves as a LPS endotoxin-sensitive trypsin type serine protease to protect the organism from bacterial infection, initiating a cascade leading to coagulin formation.[4] From the N-terminus to the C-terminus, the domains are:

This enzyme is useful in Limulus amebocyte lysate as the endotoxin-detecting element. It can be produced recombinantly.[5]

References

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  1. ^ Nakamura T, Morita T, Iwanaga S (February 1986). "Lipopolysaccharide-sensitive serine-protease zymogen (factor C) found in Limulus hemocytes. Isolation and characterization". European Journal of Biochemistry. 154 (3): 511–21. doi:10.1111/j.1432-1033.1986.tb09427.x. PMID 3512266.
  2. ^ Muta T, Miyata T, Misumi Y, Tokunaga F, Nakamura T, Toh Y, et al. (April 1991). "Limulus factor C. An endotoxin-sensitive serine protease zymogen with a mosaic structure of complement-like, epidermal growth factor-like, and lectin-like domains". The Journal of Biological Chemistry. 266 (10): 6554–61. doi:10.1016/S0021-9258(18)38153-5. PMID 2007602.
  3. ^ Tokunaga F, Nakajima H, Iwanaga S (January 1991). "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. doi:10.1093/oxfordjournals.jbchem.a123337. PMID 2016264.
  4. ^ Iwanaga S (May 2007). "Biochemical principle of Limulus test for detecting bacterial endotoxins". Proceedings of the Japan Academy. Series B, Physical and Biological Sciences. 83 (4): 110–9. Bibcode:2007PJAB...83..110I. doi:10.2183/pjab.83.110. PMC 3756735. PMID 24019589.
  5. ^ Maloney T, Phelan R, Simmons N (October 2018). "Saving the horseshoe crab: A synthetic alternative to horseshoe crab blood for endotoxin detection". PLOS Biology. 16 (10): e2006607. doi:10.1371/journal.pbio.2006607. PMC 6200278. PMID 30312293.
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