Enzyme Linked Assays Essay Example | Topics and Well Written Essays - 1250 words

Enzyme Linked Assays - Essay Example hydrogen donors in equation 2 and 3 is quite low, as a result AH2 can be a variety of compounds, and many different bindings or linkings are possible. In this way antibodies are conjugated to enzymes in order to amplify the signal via the catalytic properties of the enzymes. HRP conjugates are ideally used for ELISA or enzyme- linked immunosorbent assays. HRP has a fast catalytic rate and can generate more products in shorter incubation time, allowing for greater sensitivity. HRP-labeled antihuman IgG can be used to bind to target antigen in an assay system to localize even trace amounts of biomolecules. This biomolecules produce dityrosin bonds by reaction with HRP to produce (Adopted from Rob, P.M. et al. 2002). When used for an assay this will give rise to a reaction like Different types of linked assays and their properties: There are mainly two types of ELISA assays. 1. Sandwich. 2. Competitive. Sandwich: This is also known as two-antibody sandwich ELISA. This is used for determination of antigen concentration in unknown samples. With a purified antigen standard, it can determine absolute amount of antigen in a sample. This requires two antibodies, capture and detection, that bind to epitopes that do not overlap. Two monoclonal antibodies that recognize discrete sites on the antigen or two polyclonal affinity purified antibodies are used. The capture antibody is purified and bound to the solid phase. Antigen is added, and antigen-antibody binding occurs. This creates a sandwich. Quantification of the assay is then made by measuring the amount of labeled second antibody bound to the matrix by the use of a colourimetric substrate (Please see the picture). Competitive: Nonpurified primary antibodies may be... Kay,E., Leland, M. S., and Lew, J. Y., (1967). Peroxidase Isozymes from Horseradish Roots, Ii. Catalytic Properties, The Journal Of Biological Chemistry, Vol. 242, No. 10, Issue Of May 25, Pp. 247lbz473,