FA/VB9(Folic Acid/Vitamin B9) ELISA Kit (E-EL-0009)

This ELISA kit uses the Competitive-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with Universal FA/VB9. During the reaction, Universal FA/VB9 in the sample or standard competes with a fixed amount of Universal FA/VB9 on the solid phase supporter for sites on the Biotinylated Detection Ab specific to Universal FA/VB9. Excess conjugate and unbound sample or standard are washed away, and Avidin-Horseradish Peroxidase (HRP) conjugate are added to each micro plate well and incubated. Then a TMB substrate solution is added to each well. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns from blue to yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The concentration of Universal FA/VB9 in tested samples can be calculated by comparing the OD of the samples to the standard curve.

Folic acid, also termed vitamin B9 or folate, is a water-soluble B vitamin and an essential nutrient that the human body cannot synthesize and must obtain from the diet. Natural folates occur in leafy green vegetables, legumes, citrus fruits, liver and fortified grains, whereas synthetic folic acid is used in supplements and food fortification. After absorption both are reduced to the active coenzyme tetrahydrofolate, which functions as a carrier of one-carbon units in nucleic acid synthesis, amino acid metabolism and the methylation of DNA, proteins and lipids. The core action of folate is the transfer of one-carbon units such as methyl, formyl and methylene groups, used for de novo purine and thymidylate synthesis, for remethylation of homocysteine to methionine, and for the generation of S-adenosylmethionine, the universal methyl donor. Because this cycle is coupled to vitamin B12, deficiency of either vitamin causes homocysteine accumulation and the so-called folate trap, while folate-dependent DNA methylation underpins gene expression and epigenetic regulation. Adequate folate is critical for preventing neural tube defects in the developing fetus, and low status is associated with megaloblastic anemia and elevated homocysteine. This ELISA kit enables quantitative determination of folic acid and vitamin B9 in serum, food and pharmaceutical preparations, supporting nutritional and developmental research.