Primary Information
BoMiProt ID	Bomi4846
Protein Name	Complement C1q subcomponent subunit B
Organism	Bos taurus
Uniprot ID	Q2KIV9
Milk Fraction	Whey
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, Phosphorylation	na
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.