Enzyme conjugate

Conjugation of an enzyme to an antibody involves the formation of stable, covalent linkages. Some examples of the enzymes are: horseradish peroxidase (HRP), urease and alkaline phosphatase (AP). The antibodies are either monoclonal or polyclonal.

In ELISA, the enzyme conjugated antibody can be a primary or secondary antibody, depending on the type of ELISA performed. In either case, the enzyme amplifies the signal - the more enzyme conjugates bound in the well, the faster the products appear, the less enzyme conjugates bound in the well, the slower the products are formed. In the case of chromogenic products, when the desired color intensity is reached, the product absorbance is measured directly. In some cases, a stop solution is used to create a fixed end point in the assay.