Vasoactive intestinal polypeptide, VIP

• COA/MS/HPLC Report
• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

Vasoactive intestinal polypeptide (VIP) is a peptide consisting of 28 amino acid residues and belongs to the glucagon/secretin superfamily. VIP was first isolated as a potent vasodilator from the porcine duodenum in 1970. It is widespread in many internal organs and systems, functioning as a neurotransmitter and/or neuromodulator in both the central and peripheral nervous systems. VIP exerts its effects through two types of G protein-coupled receptors, VPAC1 and VPAC2, which stimulate cellular adenylyl cyclase activity and the protein kinase A pathway, and may also regulate other cellular pathways involving nitric oxide, phospholipase C, and MAP kinases.

In the carotid body, VIP-positive nerve fibers have been identified in numerous species including mammals, birds, and amphibians. These nerve fibers are characterized by numerous varicosities and are primarily located in connective tissue between glomus cell clusters and near blood vessels. The distribution of VIP in the carotid body shows clear interspecies differences, with VIP found in nerve fibers in most species, though in humans it has also been described in glomus cells. The number of VIP-containing nerves in the carotid body can change under various physiological and pathological factors, including hypoxia. VIP is known to impact glomus type I cells, causing changes in their spontaneous discharge, but its main impact on the carotid body is likely connected with vasodilatory effects and influence on blood flow and oxygen delivery.

• Gonkowski S. Vasoactive Intestinal Polypeptide in the Carotid Body-A History of Forty Years of Research. A Mini Review. Int J Mol Sci. 2020 Jun 30;21(13):4692. doi: 10.3390/ijms21134692. PMID: 32630153; PMCID: PMC7370131.
• Mutt V, Said SI. Structure of the porcine vasoactive intestinal octacosapeptide. The amino-acid sequence. Use of kallikrein in its determination. Eur J Biochem. 1974;42(2):581-9.
• O'Donnell M, Garippa RJ, O'Neill NC, Bolin DR, Cottrell JM. Structure-activity studies of vasoactive intestinal polypeptide. J Biol Chem. 1991 Apr 5;266(10):6389-92. PMID: 1848854.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.