Limulus clotting factor C

Limulus clotting factor C
Limulus clotting factor C
Identifiers
Organism	Tachypleus tridentatus
Symbol	?
UniProt	P28175
Structures
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Structures	Swiss-model
Domains	InterPro

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Limulus clotting factor overbar C
Limulus clotting factor overbar C
Identifiers
EC no.	3.4.21.84
CAS no.	115743-27-6
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
PMC
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PMC	articles
PubMed	articles
NCBI	proteins

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

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:

EGF-like domain
3 Sushi domains
one LCCL domain and one C-type lectin domain
2 more Sushi domains
a trypsin domain

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

References

^ 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.
^ 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.
^ 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.
^ 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.
^ 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.

External links

Limulus+clotting+factor+_overbar_C_ at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

[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.

[rfc-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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