Exendin (9-39)

Exendin (9-39) corresponds to the C-terminal part of the bioactive peptides exendin-3 and -4 isolated from the venom of Heloderma suspectum. Exendin is a potent Glucagon-Like Peptide 1 (GLP-1) receptor antagonist. It has a VIP/secretin-like biological activity. It is a competitive inhibitor of Exendin-3 and Exendin-4 when binding to the exendin receptor.

Exendin (9-39) is a synthetic research peptide in the exendin / GLP-1 receptor ligand family. Exendin-4 is a peptide agonist of the GLP-1 receptor, whereas the N-terminally truncated exendin(9-39) peptide is a well-established GLP-1 receptor antagonist. Functional expression studies directly demonstrated this agonist/antagonist relationship, and receptor-binding studies showed that exendin peptides interact strongly with the extracellular ligand-binding domain of GLP-1R. Exendin fragments and modified analogs are therefore widely used as mechanistic GLP-1 receptor probes.

• GLP-1 receptor agonist assays
• GLP-1 receptor antagonist studies
• receptor-binding competition experiments
• class B GPCR ligand-recognition studies
• analytical peptide controls

For fragments, substituted analogs, labeled peptides, stereochemical variants, or terminally modified forms, experimental behavior should be evaluated for the exact construct rather than assumed to match the native parent peptide. Sequence-dependent solubility, aggregation, adsorption, oxidation, and stability should be considered when establishing reconstitution, storage, and assay conditions.

1. Cloning and functional expression of the human islet GLP-1 receptor: exendin-4 agonism and exendin-(9-39) antagonism
2. Exendin-4 and exendin-(9-39)-amide interactions with the GLP-1 receptor