Factor D

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complement factor D (adipsin)
Factor D.jpg
Factor D in Homo sapiens [1]
Identifiers
Symbol CFD
Alt. symbols DF, PFD
Entrez 1675
HUGO 2771
OMIM 134350
RefSeq NM_001928
UniProt P00746
Other data
Locus Chr. 19 p13.3

Factor D (EC 3.4.21.46, C3 proactivator convertase, properdin factor D esterase, factor D (complement), complement factor D, CFD, adipsin) a protein which in humans is encoded by the CFD gene.[2] Factor D is involved in the alternative complement pathway of the complement system where it cleaves factor B.

Function[edit]

The protein encoded by this gene is a member of the trypsin family of peptidases. The encoded protein is a component of the alternative complement pathway best known for its role in humoral suppression of infectious agents. This protein is also a serine protease that is secreted by adipocytes into the bloodstream. Finally, the encoded protein has a high level of expression in fat, suggesting a role for adipose tissue in immune system biology.[2]

Alternative pathway. ( 4. Is factor D cleaving B to Bb and Ba)

Factor D is a serine protease that stimulates glucose transport for triglyceride accumulation in fats cells and inhibits lipolysis.[3]

Clinical significance[edit]

The level of Factor D is elevated in the obese, this elevation may be due to high activity or resistance but exact cause is not totally known.

Structure[edit]

All members of the chymotrypsin family of serine proteases have very similar structures. In all cases, including factor D, there are two antiparallel β-barrel domains with each barrel containing six β-strands with the same typology in all enzymes. The major difference in backbone structure between Factor D and the other serine proteases of the chymotrpsin family is in the surface loops connecting the secondary structural elements. Factor D displays different conformations of major catalytic and substrate-binding residues typically found in the chrotrypsin family. These features suggest the catalytic activity of factor D is prohibited unless conformational changes are induced by a realignment.[4]

References[edit]

  1. ^ PDB 1HFD; Narayana SV, Carson M, el-Kabbani O, et al. (January 1994). "Structure of human factor D. A complement system protein at 2.0 A resolution". J. Mol. Biol. 235 (2): 695–708. doi:10.1006/jmbi.1994.1021. PMID 8289289. 
  2. ^ a b "Entrez Gene: CFD". 
  3. ^ Ronti T, Lupattelli G, Mannarino E (April 2006). "The endocrine function of adipose tissue: an update". Clin. Endocrinol. (Oxf) 64 (4): 355–65. doi:10.1111/j.1365-2265.2006.02474.x. PMID 16584505. Lay summarymedscape.com. 
  4. ^ Volanakis JE, Narayana SV (April 1996). "Complement factor D, a novel serine protease". Protein Sci. 5 (4): 553–64. doi:10.1002/pro.5560050401. PMC 2143395. PMID 8845746. 

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.