Zonulin is a human protein that plays a critical role in regulating intestinal permeability by modulating the integrity of tight junctions between epithelial cells in the digestive tract. It functions as an endogenous counterpart to the zonula occludens toxin produced by Vibrio cholerae. Zonulin binds to specific receptors on the surface of intestinal epithelial cells and initiates a signaling cascade that leads to the disassembly of tight junctions. This disruption increases intestinal permeability, also referred to as “leaky gut,” allowing antigens, toxins, and pathogens to cross the intestinal barrier and potentially trigger immune responses.
In clinical and research settings, zonulin serves as a biomarker for assessing intestinal barrier function. Elevated levels of zonulin in stool or serum samples have been associated with several conditions involving intestinal permeability, including celiac disease, type 1 diabetes, irritable bowel syndrome (IBS), and inflammatory bowel diseases (IBD) such as Crohn’s disease. Measuring zonulin can help identify compromised gut barrier function and support diagnosis, disease monitoring, and evaluation of treatment efficacy in gastrointestinal and autoimmune disorders.
The Zonulin Stool ELISA is a competitive immunoassay designed for the quantitative measurement of zonulin in stool samples. A biotinylated zonulin tracer competes with native zonulin in the sample for binding to anti-zonulin antibodies immobilized on the microplate wells. Following the addition of a peroxidase-labeled streptavidin and a TMB substrate, the colorimetric reaction produces a signal that is inversely proportional to the concentration of zonulin in the sample. The reaction is stopped with an acidic solution, and absorbance is measured at 450 nm. A standard curve is then used to determine zonulin levels, providing a reliable tool for gut permeability assessment in both research and clinical practice.
This product is manufactured in Germany by Immundiagnostik AG.