STh, an Escherichia coli heat-stable toxin, is a 19 amino acid polypeptide encompassing three disulfide bridges. STh is an antigen of interest in the search for a broad coverage enterotoxigenic Escherichia coli (ETEC) vaccine.
CAT No: R1927
CAS No:118447-40-8
Synonyms/Alias:118447-40-8;STH;AKOS040756524;DA-78047;
STh, also known as heat-stable enterotoxin, is a peptide toxin produced by certain strains of Escherichia coli. Characterized by its resistance to heat denaturation, STh is a small, cysteine-rich peptide that activates membrane-bound guanylate cyclase C (GC-C) receptors in target cells, leading to increased intracellular cyclic GMP levels. Its unique biochemical properties and well-defined mechanism of action have made STh a valuable molecular tool in gastrointestinal physiology research, cellular signaling studies, and the investigation of enterotoxin-mediated pathogenesis. The peptide's structural stability and receptor specificity further enhance its utility in both basic and applied scientific contexts.
Signal transduction research: STh is widely utilized to probe the GC-C signaling pathway in epithelial cells, particularly in the context of intestinal physiology. By binding to and activating GC-C, the peptide induces a cascade resulting in elevated cGMP production, which in turn modulates ion transport and fluid secretion. Researchers employ STh to dissect the downstream effects of GC-C activation, enabling detailed analysis of second messenger systems, ion channel regulation, and the broader implications for epithelial barrier function.
Pathogenesis modeling: In studies of bacterial pathogenesis, STh serves as a model enterotoxin for elucidating the molecular mechanisms underlying diarrheagenic E. coli infections. Its application allows investigators to mimic natural toxin exposure in vitro or in animal models, facilitating the study of host-pathogen interactions, epithelial response dynamics, and the identification of cellular targets involved in disease progression. Such research supports efforts to better understand infectious diarrhea and to identify novel intervention points.
Receptor pharmacology: The peptide is instrumental in characterizing the pharmacology of GC-C and related receptor systems. By providing a highly selective agonist, STh enables precise mapping of receptor binding sites, assessment of receptor-ligand specificity, and evaluation of receptor mutations or variants. These studies inform the development of new molecular probes and contribute to the broader understanding of cyclic nucleotide signaling in various tissues.
Peptide structure-function analysis: Due to its compact, disulfide-stabilized structure, STh is frequently employed in structure-function studies of bioactive peptides. Researchers use the toxin as a model for examining the relationship between peptide conformation and biological activity, often through site-directed mutagenesis, synthetic analog development, or biophysical characterization. Insights gained from these studies advance knowledge of peptide folding, stability, and receptor interaction principles.
Analytical assay development: STh is also leveraged in the development and validation of analytical assays designed to detect heat-stable enterotoxins or to monitor GC-C activity. Its well-characterized activity profile and robust biochemical properties make it a preferred standard or positive control in assay optimization, quality control, and method validation. Such applications are essential for ensuring the reliability and reproducibility of experimental results in both academic and industrial laboratory settings.
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