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An oocytic membrane receptor for biotin‐binding protein
Author(s) -
Vieira Amandio V.,
White Harold B.,
Vieira Päivi M.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00169-x
Subject(s) - biotin , chemistry , biochemistry , receptor , biophysics , biology
The chicken oocyte accumulates a biotin‐binding protein (BBP) in the yolk that is distinct from the avidin in the ‘egg white’. An identical BBP to that of yolk is also present in the circulation of the laying hen. We report the first evidence for the existence of a BBP receptor in the oocyte vitelline membrane. Reduction of the 100 kDa receptor results in loss of BBP‐binding activity; this suggests that a disulfide‐bonded region of the receptor is necessary for maintaining BBP‐binding activity. We show further that the levels of serum BBP are strictly dependent on the presence of estrogen. As expected, BBP is not detected in significant quantities in rooster serum. Thus, these results suggest that circulatory BBP, like other estrogen‐dependent components of serum, has a cognate binding activity on the oocyte membrane that may mediate its endocytosis.