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Carbohydrate Analysis of the B 2 Bradykinin Receptor from Rat Uterus
Author(s) -
Yaqoob Mohammed,
Snell Christopher R.,
Burgess Gillian M.
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.65031290.x
Subject(s) - bradykinin , uterus , carbohydrate , receptor , chemistry , endocrinology , medicine , biochemistry , biology
The B 2 bradykinin receptor purified from rat uterus has an apparent molecular mass of 81 kDa. This is higher than the value of 42 kDa estimated from the sequence data of rat and human B 2 receptors. Carbohydrate analysis of the rat B 2 bradykinin receptor indicated that it was a sialoglycoprotein with three N‐linked complex oligosaccharide side chains. This was consistent with the sequence, which has three potential glycosylation sites. The receptor did not appear to possess O‐linked carbohydrate side chains. Removal of the N‐linked carbohydrates with endo‐β‐ N ‐acetylglucosaminidase yielded a core protein of 42–44 kDa. The presence of these N‐linked carbohydrates explains the discrepancy between the molecular size of the purified receptor protein and that estimated from the sequence. The sequence of the rat receptor suggests an isoelectric point of about pH 7.0, but the purified receptor had an isoelectric point of pH 4.5–4.7. Sialic acid residues on the N‐linked side chains are likely to be responsible for the acidic nature of the rat receptor. Carbohydrate does not appear to play a role in ligand‐receptor interactions, as deglycosylation did not alter the affinity of the B 2 bradykinin receptor for bradykinin or the B 2 ‐selective antagonist HOE‐140.