Description
Principle of the assay: human Cathepsin E ELISA Kit was based on standard sandwich enzyme-linked immune-sorbent assay technology. A monoclonal antibody from mouse specific for Cathepsin E has been precoated onto 96-well plates. Standards(NSO, Q18-P396) and test samples are added to the wells, a biotinylated detection polyclonal antibody from goat specific for Cathepsin E is added subsequently and then followed by washing with PBS or TBS buffer. Avidin-Biotin-Peroxidase Complex was added and unbound conjugates were washed away with PBS or TBS buffer. HRP substrate TMB was used to visualize HRP enzymatic reaction. TMB was catalyzed by HRP to produce a blue color product that changed into yellow after adding acidic stop solution. The density of yellow is proportional to the human Cathepsin E amount of sample captured in plate.
Background: Cathepsin E is a protein that in humans is encoded by the CTSE gene. It is mapped to 1q32.1. The protein encoded by this gene is a gastric aspartyl protease that functions as a disulfide-linked homodimer. This protease, which is a member of the peptidase C1 family, has a specificity similar to that of pepsin A and cathepsin D. It is an intracellular proteinase that does not appear to be involved in the digestion of dietary protein and is found in highest concentration in the surface of epithelial mucus-producing cells of the stomach. Cathepsin E is the first aspartic proteinase expressed in the fetal stomach and is found in more than half of gastric cancers. It appears, therefore, to be an oncofetal antigen, and it also has an important role in immune responses