Vitamin B2 (Riboflavin)

Vitamin B2 is a microtiter plate test kit based on a microbiological assay which measures the total Vitamin B2 content in serum. The test kit contains all required reagents, e.g. standard, medium and microtiter plate coated with a specific microorganism, sufficient for 96 determinations including standard curves. An ELISA reader is required for evaluation of the Vitamin B2 content. Vitamin B2 is a component of the flavin-nucleotides and as such is involved in the transport of hydrogen ions and electrons. It is an essential coenzymefor the metabolism of carbohydrates, fats and proteins. The biological form of vitamin B2 is riboflavin-5-phosphate. The most important vitamin B2 derivativesare flavin mononucleotide (FMN) and flavin-adenine dinucleotide (FAD). In blood, about 60% of FAD and FMN are protein bound; only about 0.5 – 2 % occurin free form. Riboflavin-5-phosphate, FMN, and FAD are transported in the plasma by a variety of proteins, including albumin, fibrinogen, riboflavin-binding protein and other globulins. Although vitamin B2 is eliminated regularly in the urine, its determination in urine samples is not recommended because of fluctuations in the concentration.Diluted serum samples are transferred in the wells of a microtiter plate coated with Lactobacillus rhamnosus. The addition of Vitamin B2 in either standards or samples gives a Vitamin B2-dependent growth response until Vitamin B2 is consumed. After incubation at 37 °C for 48 hr, the growth of Lactobacillus rhamnosus is measured turbidimetrically at 610 - 630 nm (alternatively at 540 - 550 nm) in an ELISA-reader and a standard curve is generated from the dilution series.The amount of Vitamin B2 is directly proportional to the turbidity.