Proguanylin Human

Heat-stable enterotoxins (STa), produced by Escherichia coli, are small, cysteine-rich peptides that can cause diarrhea. They achieve this by stimulating an intestine-specific receptor-guanylyl cyclase called STaR. This stimulation significantly increases the cell's cGMP content, leading to reduced salt absorption and increased chloride secretion in the intestines. This ion imbalance causes a large accumulation of water in the gut, resulting in diarrhea and dehydration, characteristic effects of enterotoxin activity. The discovery of an STa receptor on intestinal brush border membranes pointed towards the existence of an endogenous activator. This led to the identification of guanylin, a 15-amino acid peptide purified from rat small intestine, as a potential ligand for STaR. Guanylin shares sequence similarity with STa (see also uroguanylin). The human and mouse cDNAs encoding guanylin have been cloned, revealing that guanylin exists at the C-terminal end of a larger precursor protein. When expressed in mammalian cells, the 94-amino acid proguanylin is inactive. The active form of guanylin is released from proguanylin through chemical or enzymatic cleavage. Studies using Northern blot analysis and in situ hybridization have shown that guanylin mRNA expression is limited to intestinal epithelial cells, particularly Paneth cells located at the base of small intestinal crypts. These findings confirm that guanylin acts as an endogenous activator of STaR. Further research led to the isolation of a cDNA encoding a likely precursor of guanylin from a human intestinal cDNA library. High levels of this mRNA were found in the human ileum and colon. In mice, interspecific backcross analysis was used to map the Guca2 gene to the distal half of mouse chromosome 4, a region homologous to human chromosome 1p. Using fluorescence in situ hybridization, the GUCA2 gene was mapped to human chromosome 1p35-p34. Guanylin is believed to regulate intestinal water and electrolyte transport via paracrine signaling. Further studies have described the gene's nucleotide sequence, the characteristics of its circulating form, and its localization within enterochomaffin cells of the gut. The gene, approximately 2.6 kb in size, comprises three exons interspersed with two introns. The active form of guanylin is a 94-amino acid peptide with a molecular mass of 10.3 kDa. It is synthesized by gut enterochomaffin cells as a 115-amino acid prohormone and then processed into the 94-amino acid form that circulates in the blood.

Recombinant Human Proguanylin, produced in E. coli, is a single, non-glycosylated polypeptide chain containing 104 amino acids. This includes a 10 amino acid N-terminal His tag and amino acids 22-115 of the Proguanylin sequence. The calculated molecular mass is 11.5 kDa.

Sterile Filtered White lyophilized (freeze-dried) powder.

Proguanylin is filtered through a 0.4 µm filter and lyophilized in deionized water at a concentration of 0.5 mg/ml.

To create a working stock solution, add deionized water to the lyophilized pellet to achieve a concentration of approximately 0.5 mg/ml and ensure complete dissolution. Please note that Proguanylin is not sterile. Before use in cell culture, it must be filtered through an appropriate sterile filter.

Lyophilized Proguanylin should be stored at -20°C. After reconstitution, aliquot the protein to avoid repeated freeze-thaw cycles. The reconstituted protein remains stable at 4°C for a limited period, showing no significant change after one week.

Purity is determined to be greater than 90.0% as assessed by SDS-PAGE.

Guanylin Precursor, Guanylate cyclase activator 2A, Guanylate cyclase-activating protein 1, Gap-IGUCA2, STARA, GUANYLIN.

Escherichia Coli.

MKHHHHHHAS VTVQDGNFSF SLESVKKLKD LQEPQEPRVG KLRNFAPIPG EPVVPILCSN PNFPEELKPL CKEPNAQEIL QRLEEIAEDP GTCEICAYAA CTGC.