Description
Introduction: Pepsin is an enzyme that is released by the chief cells in the stomach and that degrades food proteins into peptides. Pepsin was discovered in 1836 by Theodor Schwann. It was the first animal enzyme to be discovered, and, in 1929, it became one of the first enzymes to be crystallized, by John H. Northrop. Pepsin is one of three principal protein-degrading, or proteolytic, enzymes in the digestive system, the other two being chymotrypsin and trypsin. Pepsin functions best in acidic environments and is often found in an acidic environment, particularly those with a pH of 1.5 to 2. Pepsin denatures if the pH is more than 5.0. Pepsin is said to have an optimum temperature between 37 degree C and 42 degree C in humans. Pepsin is potently inhibited by the peptide inhibitor pepstatin.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to PG. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for PG and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain PG, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm +/- 2 nm. The concentration of PG in the samples is then determined by comparing the O.D. of the samples to the standard curve