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complement factor B

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Target id: 2339

Nomenclature: complement factor B

Family: S1: Chymotrypsin

Gene and Protein Information Click here for help
Species TM AA Chromosomal Location Gene Symbol Gene Name Reference
Human - 764 6p21.33 CFB complement factor B
Mouse - 761 17 18.41 cM Cfb complement factor B
Rat - 763 20p12 Cfb complement factor B
Previous and Unofficial Names Click here for help
alternative-complement pathway C3/C5 convertase | B-factor, properdin | BFD | C2 | Factor B | H2-Bf | histocompatibility 2, complement component factor B | properdin factor B
Database Links Click here for help
Specialist databases
MEROPS S01.196 (Hs)
Other databases
ChEMBL Target
Ensembl Gene
Entrez Gene
Human Protein Atlas
KEGG Enzyme
RefSeq Nucleotide
RefSeq Protein
Enzyme Reaction Click here for help
EC Number:

Download all structure-activity data for this target as a CSV file go icon to follow link

Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
iptacopan Small molecule or natural product Approved drug Ligand has a PDB structure Immunopharmacology Ligand Hs Inhibition 7.9 pIC50 2
pIC50 7.9 (IC50 1.2x10-8 M) [2]
Description: Determined in a FRET competition binding assay with factor B and a Cy5-labeled small-molecule inhibitor as probe.
compound 51 [PMID: 19743866] Small molecule or natural product Hs Inhibition 6.6 pIC50 3
pIC50 6.6 (IC50 2.5x10-7 M) [3]
Immunopharmacology Comments
A protease component of the alternative complement pathway. Cleaved by complement factor D into a non-catalytic and catalytic fragment (Ba and Bb respectively).
Immuno Process Associations
Immuno Process:  Inflammation
Immuno Process:  Immune regulation
Clinically-Relevant Mutations and Pathophysiology Click here for help
Disease:  Complement factor B deficiency; CFBD
OMIM: 615561
Disease:  Hemolytic uremic syndrome, atypical, susceptibility to, 4
Synonyms: Atypical hemolytic-uremic syndrome with B factor anomaly [Orphanet: ORPHA93578]
Hemolytic-uremic syndrome [Disease Ontology: DOID:12554]
Disease Ontology: DOID:12554
OMIM: 612924
Orphanet: ORPHA93578
Disease:  Macular degeneration, age-related, 14; ARMD14
Synonyms: Age-related macular degeneration [Orphanet: ORPHA279] [Disease Ontology: DOID:10871]
Disease Ontology: DOID:10871
OMIM: 615489
Orphanet: ORPHA279
References:  1
Click column headers to sort
Type Species Amino acid change Nucleotide change Description Reference
Missense Human L9H 26T>A This variant is associated with reduced risk of age-related macular degeneration when inherited with the E318D variant of the C2 gene as part of haplotype 10. 1


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1. Gold B, Merriam JE, Zernant J, Hancox LS, Taiber AJ, Gehrs K, Cramer K, Neel J, Bergeron J, Barile GR et al.. (2006) Variation in factor B (BF) and complement component 2 (C2) genes is associated with age-related macular degeneration. Nat Genet, 38 (4): 458-62. [PMID:16518403]

2. Mainolfi N, Ehara T, Karki RG, Anderson K, Mac Sweeney A, Liao SM, Argikar UA, Jendza K, Zhang C, Powers J et al.. (2020) Discovery of 4-((2S,4S)-4-Ethoxy-1-((5-methoxy-7-methyl-1H-indol-4-yl)methyl)piperidin-2-yl)benzoic Acid (LNP023), a Factor B Inhibitor Specifically Designed To Be Applicable to Treating a Diverse Array of Complement Mediated Diseases. J Med Chem, 63 (11): 5697-5722. [PMID:32073845]

3. Ruiz-Gómez G, Lim J, Halili MA, Le GT, Madala PK, Abbenante G, Fairlie DP. (2009) Structure-activity relationships for substrate-based inhibitors of human complement factor B. J Med Chem, 52 (19): 6042-52. [PMID:19743866]

How to cite this page

S1: Chymotrypsin: complement factor B. Last modified on 03/03/2020. Accessed on 21/06/2024. IUPHAR/BPS Guide to PHARMACOLOGY,