Search by BoMiProt ID - Bomi4846

Primary Information

BoMiProt ID Bomi4846
Protein Name Complement C1q subcomponent subunit B
Organism Bos taurus
Uniprot IDQ2KIV9
Milk FractionWhey
Ref Sequence ID NP_001040064.1
Aminoacid Length 247
Molecular Weight 26399
FASTA Sequence Download
Gene Name C1QB
Gene ID 617435
Protein Existence Status reviewed

Secondary Information

Protein Function C1q associates with the proenzymes C1r and C1s to yield C1, the first component of the serum complement system. The collagen-like regions of C1q interact with the Ca(2+)-dependent C1r(2)C1s(2) proenzyme complex, and efficient activation of C1 takes place on interaction of the globular heads of C1q with the Fc regions of IgG or IgM antibody present in immune complexes.
Significance in milk role in immune system
PTMs Disulfide bond formation, Glycosylation, Hydroxylation, Pyrrolidone carboxylic acid addition
Site(s) of PTM(s)

N-glycosylation, O-glycosylation,
Predicted Disorder Regions 3 predicted segments; (20-23), (28-131), (145-149)
DisProt Annotation
TM Helix Prediction No TM helices
Significance of PTMs Hydroxylated on lysine and proline residues. Hydroxylated lysine residues can be glycosylated. Bovine C1Q contains up to 66.3 hydroxylysine-galactosylglucose residues. Total percentage hydroxylysine residues glycosylated is 92.0%. Contains no hydroxylysine-monosaccharides.
Bibliography 1.Yonemasu K, Shinkai H, Sasaki T. Comparable content of hydroxylysine-linked glycosides in subcomponents C1q of the first component of human, bovine and mouse complement. Coll Relat Res. 1981 Jul;1(4):385-90. doi: 10.1016/s0174-173x(81)80015-5. PMID: 6286235. 2.Reid KB, Porter RR. Subunit composition and structure of subcomponent C1q of the first component of human complement. Biochem J. 1976 Apr 1;155(1):19-23. doi: 10.1042/bj1550019. PMID: 938474; PMCID: PMC1172797.