Chromogenic substrates, enzyme linked

Enzyme-linked immunosorbent assays (ELISA) are by far the most common immunological assay used in biochemical and clinico-chemical laboratories (Crowther 1995). The method is just as specific as RIA and it can achieve comparable sensitivities under optimal conditions. It can be carried out in various ways, but the common feature is that detection relies on turnover of a chromogenic substrate by an... 

Such chromogenic enzymes can also be fused or chemically linked to an antibody and used to report the presence or location of the antigen. Alternatively, luciferase, an enzyme present in fireflies and some bacteria, can be linked to an antibody. In the presence of ATP and luciferin, luciferase catalyzes a light-emitting reaction. In either case, after the antibody binds to the protein of Interest, substrates of the linked enzyme are added and the appearance of color or... 

The specific activities of purified preparations of human parotid and pancreatic amylases towards Amylose Azure, Remazol Brilliant Blue starch, phosphate-derivatized starch, and cross-linked starch have been measured. The activities varied with the physical state of the substrate the parotid enzyme exhibited a higher specific activity towards all soluble starches, whereas the pancreatic amylase was more active towards insoluble chromogenic starches. Variations in the enzyme-substrate interactions support the view that there is a configurational difference between the amylases this may be useful in determining the proportions of these amylases in normal and pathological body fluids. 

---