What is the role of the enzyme in the Enzyme-Linked Immunosorbent Assay (ELISA)?

In the context of the Enzyme-Linked Immunosorbent Assay (ELISA), the primary role of the enzyme is to produce a color change signal. This signal is a crucial aspect of the assay because it allows for the quantification of the target analyte present in the sample.

In an ELISA, an antigen (or antibody) is immobilized on a solid surface, and a sample containing the analyte is added. After incubation, a secondary antibody linked to an enzyme is introduced. The enzyme catalyzes a reaction that results in a color change when a specific substrate is added, which can be measured using a spectrophotometer. The intensity of the color is directly proportional to the amount of analyte present in the sample, thus facilitating the quantification of the analyte.

This enzymatic action is fundamental to the sensitivity and specificity of the ELISA, providing a visual representation of the amount of target substance in the sample.