GLP-3 RT research peptide: identity and published literature

What GLP-3 RT is

GLP-3 RT, catalogued as GLP-3RT, is a synthetic 39-residue peptide whose sequence corresponds to a chemically modified backbone drawn from the glucagon and incretin peptide family. The catalogue classes the material as a GIP, GLP-1 and glucagon receptor agonist peptide analogue: a single synthetic chain designed to carry affinity for three related class B G-protein-coupled receptors at once, namely the receptors for glucose-dependent insulinotropic polypeptide, for glucagon-like peptide-1 and for glucagon. That three-way design is what separates it structurally from the single-receptor and dual-receptor analogues catalogued alongside it.

The catalogue records the material as investigational and states that it has not been approved by the U.S. Food and Drug Administration for general clinical use. It is supplied strictly as a laboratory research material and is not for human or veterinary use, nor for consumption, administration, diagnostic use or therapeutic use.

Peptides of this class are assembled by solid-phase synthesis. Two modification strategies are general to the class: non-natural residues such as alpha-aminoisobutyric acid are substituted at otherwise cleavage-sensitive positions, and a fatty-acid or fatty-diacid moiety is attached through a linker to a lysine side chain. The first raises resistance to proteolysis in in-vitro degradation assays and the second promotes reversible association with serum albumin. The catalogue entry for GLP-3 RT does not enumerate which substitutions it carries or where they sit, so no specific modification pattern is asserted here. The material is listed in the cell-biology section of the catalogue and no alternative catalogue synonyms are recorded for it.

Structure and identifiers

The catalogue describes GLP-3 RT as a chemically modified peptide of 39 amino acids. Its full residue sequence and the exact positions of its modifications are not recorded in the catalogue entry, so this guide states no sequence and no substitution list. The identifier that is recorded is the molecular formula, C221H342N46O68, a composition consistent with a single-chain peptide of this length carrying a non-peptidic side-chain extension.

A CAS registry number is not catalogued here, and a molecular weight is not catalogued here either, so neither value appears on this page. The certificate of analysis issued with each lot reports the mass measured for that specific material, which is the appropriate numerical reference for identity work rather than a figure quoted from a catalogue description.

The material is offered in a single 10 mg vial format and is supplied lyophilized. Lyophilized peptides of this type are handled as dry solids until they are reconstituted in an appropriate laboratory diluent, and the dry state is the form in which the identifiers above apply.

What the published literature has examined

Published work has examined peptides of this class in receptor-signaling, ligand-binding and peptide-stability models within molecular endocrinology and cell biology. The papers listed on this page are bibliographic references only; they are not evidence of safety or efficacy and describe laboratory findings, not any use in people or animals.

No bibliographic references are attached to this catalogue entry. The published literature on multi-receptor incretin and glucagon receptor agonist peptide analogues is predominantly clinical and regulatory in character, and the catalogue therefore treats GLP-3 RT as a research material only. It lists no reference set for the material, and no findings from that clinical or regulatory literature are summarised, quoted or otherwise described anywhere on this page.

The research context recorded for the material is narrower than that wider literature. The catalogue description places GLP-3 RT in experimental glucagon, GIP and GLP-1 receptor-signaling models. A triple-agonist design shapes how such experiments are built: the same molecule is profiled against each of the three receptors separately, so recombinant glucagon receptor, GIP receptor and GLP-1 receptor preparations are expressed in parallel transfected cell lines and read on matched assays, with the three readouts held on the same scale so that the profile can be compared position by position. Formats used in that work include cyclic-AMP accumulation and beta-arrestin recruitment reporters, radioligand and fluorescent competition-binding assays, receptor internalisation imaging, and cell-free enzymatic incubations with dipeptidyl peptidase-4 or with plasma fractions followed by a chromatographic readout.

Analytical methods that appear in work of this kind include reverse-phase HPLC for separation, liquid chromatography coupled to mass spectrometry for fragment identification, circular dichroism for secondary-structure assessment, and surface plasmon resonance for binding kinetics. The preceding two paragraphs describe methodology and study design only. No result, potency value, selectivity ratio or comparison from any study is stated here.

Storage and handling as a laboratory reagent

No compound-specific storage rows are recorded in the catalogue entry, so the general handling profile for lyophilized research peptides applies. In lyophilized form the vial is held at -20 C, protected from light, and kept sealed until it is opened in the laboratory. Allowing a cold vial to reach room temperature before it is opened keeps condensation from forming on the dry solid, which is the ordinary practice for a hygroscopic lyophilisate.

Once reconstituted, the material is a short-lived laboratory reagent rather than a stock. Reconstituted solutions are held refrigerated at 2 to 8 C for short-term laboratory use, kept out of direct light, and protected from repeated freeze-thaw cycling, which is a common cause of aggregation and of drifting concentration in peptide work. Where a solution has to be held beyond a short working window, dividing it into single-use aliquots at the point of reconstitution avoids warming the whole volume more than once.

Concentrations are worked out before diluent goes into the vial. The reconstitution calculator converts a vial mass and a target concentration into a diluent volume, and bacteriostatic water is the diluent most commonly catalogued for laboratory vials that will be entered more than once.

Analytical verification

Identity and purity for this material are established analytically rather than by description. Purity is assessed by third-party reverse-phase HPLC, where the chromatogram separates the target peptide from synthesis-related species such as deletion sequences, incompletely deprotected intermediates and oxidation products, and purity is reported as the target peak area relative to the total integrated peak area. Identity is assessed by mass spectrometry against the expected molecular weight for the peptide and its modifications, so that the measured mass confirms the molecule present is the one the catalogue entry names. A certificate of analysis is issued for each lot, and the certificates are held in the certificate library.

Two related articles cover how those documents are read. Peptide identity testing by mass spectrometry explains what an identity result establishes and what it leaves open, which matters for a long modified chain where several candidate structures share a similar mass. What 99 percent peptide purity means explains what a chromatographic purity percentage counts and what it does not count, including water, counter-ions and residual solvent. Purity and identity information on this page is limited to exactly that: third-party HPLC and mass spectrometry, with one certificate per lot. No purity figure, lot number or testing-laboratory name is stated here, because those values belong to individual lots and are reported on the certificate for the lot supplied.