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  • E5763 - Escherichia coli heat-stable enterotoxin STa

E5763 Sigma

Escherichia coli heat-stable enterotoxin STa

lyophilized powder, ~100,000 units/mg protein (HPLC)



Related Categories Bacteria, Cell Biology, Cell Signaling and Neuroscience, Toxins and Venoms
form   lyophilized powder
mol wt   mol wt 1,972 Da
solubility   aqueous buffer: ≥5 mg/mL (More soluble under acidic conditions)
storage temp.   −20°C


Biochem/physiol Actions

STa has a tertiary structure, maintained by disulfide bridges, which is required for receptor binding and biological activity. Its receptors are membrane-bound guanylyl cyclases. These receptors are located on enterocytes, colonocytes, and various extraintestinal tissues. STa causes diarrhea in humans by binding to its receptor, stimulating the guanylyl cyclase, and triggering production of cyclic GMP. Endogenous ligands for the STa receptor include guanylin, extracted from intestine, and uroguanylin from urine. These peptides may have a role in the regulation of fluid and electrolytes. Protein kinase C (PKC) phosphorylates and activates the STa receptor/guanylyl cyclase in vitro and in vivo. As a result, stimulators of PKC synergistically enhance STa effects on cGMP and secretion.

Other Notes

E. coli STa is a heat-stable peptide toxin.

Unit Definition

One unit is the amount of toxin which produces an intestinal weight/carcass weight ratio of ≥0.083 in 3-day-old mice.

Price and Availability

All labs need water
Safety & Documentation

Safety Information

UN 3462 6.1/PG 1
WGK Germany 


Certificate of Analysis

Certificate of Origin

Protocols & Articles
Peer-Reviewed Papers


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