Isolation and characterisation of a biotin-binding protein from the pregnant-rat serum and comparison with that from the chicken egg-yolk.
A biotin-binding protein exhibiting partial immunological cross-reactivity with the purified chicken egg-yolk biotin-binding protein has been detected, for the first time, in the sera of pregnant/estrogenised female rats but not of the normal males. This protein, purified by affinity chromatography on a biotin-AH-Sepharose was homogeneous by electrophoretic and immunological criteria. It was a glycoprotein of Mr 66,000 without any detectable subunites, had a pI 4.1, and specifically bound [14C]biotin. Several structural and functional features of the biotin-binding protein of rat and chicken were found to be similar. These included immunological cross-reactivity, acidic and glycoprotein nature, ability to tightly bind [14C]biotin, estrogen stimulation for their appearance in circulation, and the pattern of distribution of radioiodinated peptides upon proteolysis with trypsin.
D000818:Animals; D001710:Biotin / Q000378:metabolism; D002352:Carrier Proteins / Q000302:isolation & purification*; D002645:Chickens; D003429:Cross Reactions; D004530:Egg Yolk / Q000032:analysis*; D005260:Female; D005779:Immunodiffusion; D007526:Isoelectric Point; D008970:Molecular Weight; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains
D002352:Carrier Proteins; C017071:biotin-binding proteins; D001710:Biotin