Substrate
Definition
The compound converted by the reporter enzyme into a coloured product. For HRP, 3,3',5,5'-tetramethylbenzidine (TMB) is the standard substrate, producing a blue product that turns yellow after the stop reagent is added. The intensity of colour is proportional to enzyme activity, which is proportional to the amount of bound analyte.
Related terms
- Competitive ELISA
- An ELISA format in which sample antigen competes with a fixed quantity of labelled antigen for a limited number of antibody binding...
- Cross-reactivity
- The capacity of an antibody raised against one analyte to bind structurally related compounds. In RIA, cross-reactivity is the main driver of...
- Enzyme conjugate
- An antibody (or antigen) chemically linked to a reporter enzyme, most commonly horseradish peroxidase (HRP) or alkaline phosphatase (AP). The enzyme catalyses...
- Sandwich ELISA
- An ELISA format in which a capture antibody immobilised on the plate binds one epitope of the target antigen, and a separate...
- Solid phase
- The inert surface to which an antigen or antibody is adsorbed at the start of an ELISA. Usually the well walls of...
Explained in
- ELISA: Principles, Formats, and Forensic ApplicationsThe compound converted by the reporter enzyme into a coloured product. For HRP, 3,3',5,5'-tetramethylbenzidine (TMB) is the standard substrate, producing a blu...