Development of an Egg-white Bioassay for Monitoring Biotin Levels in Urine and Serum

Abstract

This article reports on the development of a simple and cost-effective bioassay for the detection of biotin in urine and serum, based on the very selective binding of avidin and biotin. Avidin was allowed to react without isolating it from egg white. Egg white was treated with the dye HABA, which binds to avidin. Upon subsequent treatment with biotin, HABA is released due to the high affinity of biotin to avidin. The amount of HABA released is proportional to the amount of biotin used.

Use of Nutritional Requirements for Brettanomyces bruxellensis to Limit Infections in Wine

“…Because biotin was required by all strains examined and concentrations were correlated to growth in media, the possibility that making this vitamin unavailable to limit spoilage in a commercial wine was evaluated. Avidin, a protein found in egg white [37], selectively binds biotin [38] and has been applied as a means to remove biotin from chemical solutions [39,40]. With dissociation constants (K d ) of 10 −15 M at neutral pH, this binding complex is one of the strongest bonds known [38].…”

“…However, avidin can also react with phenolics present in wine [42], thereby rendering the protein inactive against biotin. To compensate, dialysis tubing with small enough porosity to prevent the migration of most phenolics (1000 MWCO) has been used [40].…”