Search by BoMiProt ID - Bomi133

Primary Information

BoMiProt ID Bomi133
Protein Name Complement factor B
Organism Bos taurus
Uniprot IDP81187
Milk FractionWhey
Ref Sequence ID NP_001035616.1
Aminoacid Length 761
Molecular Weight 85366
FASTA Sequence Download
Gene Name CFB
Gene ID 514076
Protein Existence Status Reviewed: Experimental evidence at protein level

Secondary Information

Protein Function key glycoprotein in the alternative pathway of complement activation; role in assembly of the C3 convertase complex by association with a C3b molecule; unusual type of serine proteinase. Complement component factor B (Bf), the second component of the alternative complement pathway, has thrombin-like activity, which is supported by a characteristic homology of the trypsin-like domain of Bf to that of thrombin. 
Biochemical Properties Bb fragment contains 11 cysteine residues; three commonly conserved disulphide bonds are present and are represented by disulphide bridges linking Cys-252 to Cys-286, Cys-396 to Cys-423 and Cys-436 to Cys-466; homology with thrombin; sequence containing the catalytic residues is considerably longer than that of other serine proteinases;
Significance in milk immune protection against environmental pathogens
PTMs Glycosylated; glucose is covalently attached; sialylated complex biantennary sugars
Site(s) of PTM(s)

N-glycosylation, O-glycosylation,
Predicted Disorder Regions NA
DisProt Annotation
TM Helix Prediction No TM helices
Significance of PTMs N-linked oligosaccharide may be involved in the regulation of FB binding to C3b
Bibliography 1. Christie, D. L., & Gagnon, J. (1983). Amino acid sequence of the Bb fragment from complement factor B. Sequence of the major cyanogen bromide-cleavage peptide (CB-II) and completion of the sequence of the Bb fragment. Biochemical Journal, 209(1), 61–70.
2. Niemann, M. A., Bhown, A. S., & Miller, E. J. (1991). The principal site of glycation of human complement Factor B. Biochemical Journal, 274(2), 473–480.
3. Rainard, P. (2002). Complement factor B and the alternative pathway of complement activation in bovine milk. The Journal of Dairy Research, 69(1), 1–12.
4. Davrinche, C., Abbal, M., & Clerc, A. (1990). Molecular characterization of human complement factor B subtypes. Immunogenetics, 32(5), 309–312. 5.Takahashi K, Banda NK, Holers VM, Van Cott EM. Complement component factor B has thrombin-like activity. Biochem Biophys Res Commun. 2021 May 7;552:17-22. doi: 10.1016/j.bbrc.2021.02.134. Epub 2021 Mar 16. PMID: 33740660; PMCID: PMC8035301.