complement factor B | S1: Chymotrypsin | IUPHAR/BPS Guide to PHARMACOLOGY

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complement factor B

target has curated data in GtoImmuPdb

Target id: 2339

Nomenclature: complement factor B

Family: S1: Chymotrypsin

Annotation status:  image of a grey circle Awaiting annotation/under development. Please contact us if you can help with annotation.  » Email us

Gene and Protein Information
Species TM AA Chromosomal Location Gene Symbol Gene Name Reference
Human - 764 6p21.3 CFB complement factor B
Mouse - 763 17 B1 Cfb complement factor B
Rat - 763 20p12 Cfb complement factor B
Previous and Unofficial Names
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
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
EC Number:

Download all structure-activity data for this target as a CSV file

Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
LNP023 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] 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
GO Annotations:  Associated to 1 GO processes
GO:0006957 complement activation, alternative pathway TAS
Immuno Process:  Immune regulation
GO Annotations:  Associated to 3 GO processes
GO:0006956 complement activation TAS
GO:0006957 complement activation, alternative pathway TAS
GO:0030449 regulation of complement activation TAS
Clinically-Relevant Mutations and Pathophysiology
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 04/07/2020. IUPHAR/BPS Guide to PHARMACOLOGY,