Enzyme protein binding assay

Enzyme protein binding assay Based on competitive reaction between folate isomers and folate binding protein. 

Protein-binding assays Several enzyme protein-binding assays and radio-protein-binding assays have also been developed and commercialized as kits for rapid evaluation of this vitamin in blood, plasma, and different foodstuffs. Despite their rapidity, these methods lack adequate discrimination between different forms of folates. 

A classical approach is the enzyme linked immunosorbent assay (ELISA), where the antigen (e.g., the protein to be quantified) is immobilized on the surface of a well. A first antigen-specific antibody is applied to occupy all antigens, before a second antibody binds all primary antibodies on the well. The second antibody carries an enzyme, which now catalyzes a color reaction. If the substrate of the enzyme is given in high excess, the enzyme is saturated and the production of product is linear with time and concentration of second antibody and antigen (Fig. 8). 

Enzyme assays—both kinetic and end-point radiocoordination of proteins, lipid assays, receptor binding assays and tissue-culture techniques... 

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