Vasoactive intestinal peptide is a 28-residue member of the secretin-glucagon superfamily (sequence HSDAVFTDNYTRLRKQMAVKKYLNSILN, molecular weight about 3,326 Da), first isolated from porcine duodenum by Said and Mutt in 1970. It shares roughly 68 percent sequence identity with PACAP and signals through two class B G protein-coupled receptors, VPAC1 and VPAC2, both of which bind VIP with nanomolar affinity. Supplied lyophilised for laboratory research.
Research Summary
VPAC1 is broadly expressed on macrophages, dendritic cells and T lymphocytes as well as gut mucosa, lung epithelium and cerebral cortex, and couples mainly through G-alpha-s to adenylyl cyclase. VPAC2 expression is concentrated in the suprachiasmatic nucleus, pancreatic islets, smooth muscle and type 2 innate lymphoid cells, and shows higher constitutive activity. Couvineau and Laburthe (Frontiers in Endocrinology, 2012) mapped the receptor domains that govern VIP binding and subtype selectivity. Preclinical work has examined VIP in smooth muscle relaxation, circadian entrainment, suppression of proinflammatory cytokine cascades and promotion of regulatory T cell differentiation in rodent models. The receptor pharmacology is reviewed in VIP VPAC receptor and neuroimmune research.
VIP is one of the least stable peptides in a research catalogue. Its circulating half-life is under two minutes because neutral endopeptidase and dipeptidyl peptidase IV cleave it at several sites, and the single methionine at position 17 oxidises in solution exposed to air, the same sulfoxide chemistry described for methionine oxidation in TB-500. Reconstituted material should be prepared fresh and kept cold, and a VIP certificate of analysis is only informative if the chromatogram resolves the oxidised species from the parent peak. The general pathways are covered in peptide degradation pathways.
Storage and Handling
Store the sealed lyophilised vial at minus 20 degrees Celsius for long-term preservation, or 2 to 8 degrees Celsius for short-term storage. After reconstitution, store at 2 to 8 degrees Celsius and protect from light. Allow vials to equilibrate to room temperature before opening to limit condensation.
For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.
Related Research Reading
Third-party analytical reports are listed on the Certificates of Analysis page, with reading guidance under Documentation.
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