Quantitative determination of biotin in food, cosmetic, and biotinylated proteins.

• Fast and sensitive: linear detection range - 8 to 200 µm biotin with 30 µl sample (96-well) or 10 to 200 µm biotin with 10 µl sample (384-well)
• Method: OD 500 nm
• Samples: food, cosmetics, supplements, and biotinylated proteins or antibodies

BIOTIN , or Vitamin B7, is a water soluble vitamin involved in metabolism, cell growth, and protein synthesis. It is a cofactor to multiple carboxylases necessary for metabolizing fatty acids, glucose, and amino acids. Biotin is found in a wide range of foods and is often taken as a dietary supplement. In the biotechnology industry, biotin is commonly conjugated to proteins in a process called biotinylation. These biotinylated proteins can then be specifically selected using streptavidin and/or avidin's strong affinity for biotin in biochemical assays such as ELISAs.

BioAssay Systems' Biotin Assay Kit is based on avidin's weak affinity for 4'-hydroxyazobenzene-2-carboxylic acid (HABA) and strong affinity for biotin. The avidin-HABA complex reagent has an absorbance at 500nm. When the colored avidin-HABA reagent is introduced to biotin, the biotin binds to avidin, displacing the HABA and causing a decrease in absorbance. The decrease in absorbance at 500nm is directly proportional to the biotin in the sample.