Role of human serum biotinidase as biotin-binding protein.
Biotinidase shows two binding sites for biotin, with Kd = 59 and 3 nM respectively, and requires tryptophan and cysteine residues of the biotinidase protein for biotin-binding activity. Analysis of human serum by various column-chromatographic techniques indicates that biotinidase is the only protein which exchanges with labelled (+)-biotin. It was shown previously that epileptic patients receiving a high average dose of anticonvulsants (containing a carbamide group) have lower biotin concentrations than those receiving a low dose. We have shown in human serum and with purified biotinidase that these anticonvulsant drugs compete with biotin for binding to the protein moiety.
Chauhan
J
J
Department of Biochemistry, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Dakshinamurti
K
K
D000581:Amidohydrolases / Q000097:blood*; D001665:Binding Sites; D001710:Biotin / Q000378:metabolism*; D043523:Biotinidase; D001974:Bromosuccinimide / Q000494:pharmacology; D002220:Carbamazepine / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D002729:Chloromercuribenzoates / Q000494:pharmacology; D002850:Chromatography, Gel; D005916:Globulins / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010634:Phenobarbital / Q000494:pharmacology; D010672:Phenytoin / Q000494:pharmacology; D012709:Serum Albumin / Q000378:metabolism; D020245:p-Chloromercuribenzoic Acid
D002352:Carrier Proteins; D002729:Chloromercuribenzoates; D005916:Globulins; D012709:Serum Albumin; C017071:biotin-binding proteins; D002220:Carbamazepine; D020245:p-Chloromercuribenzoic Acid; D010672:Phenytoin; D001710:Biotin; D000581:Amidohydrolases; D043523:Biotinidase; D001974:Bromosuccinimide; D010634:Phenobarbital