* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. For research purposes only.
The biologically active form of glucagon-like peptide-1 listed by Evo Amino is GLP-1 (7-37), a 31-residue peptide with the sequence His-Ala-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln-Ala-Ala-Lys-Glu-Phe-Ile-Ala-Trp-Leu-Val-Lys-Gly-Arg-Gly, written in one-letter code as HAEGTFTSDVSSYLEGQAAKEFIAWLVKGRG. The numbering starts at 7 rather than 1 because the peptide was originally identified as a 37-residue product of proglucagon, and the first six residues of that product were later found to be removed during processing. GLP-1 at Evo Amino is supplied as this 7-37 form for research use.
What is the molecular weight of GLP-1?
GLP-1 (7-37) has the molecular formula C₁₅₁H₂₂₆N₄₀O₄₆ and a molecular weight of 3337.73 g/mol, with CAS number 106612-94-6. The 7-36 amide form is one residue shorter (the terminal glycine is removed and the arginine is amidated) and correspondingly lighter, near 3298 g/mol. Searches for "GLP-1 molecular weight" return both figures depending on which form the source is describing, and the difference is the C-terminal glycine plus the amidation.
What is the difference between GLP-1 (7-36) amide and GLP-1 (7-37)?
GLP-1 (7-36) amide is the predominant circulating form in humans, produced when the terminal glycine of the 7-37 form is removed by peptidylglycine alpha-amidating monooxygenase and its amino group left as a C-terminal amide on arginine 36. GLP-1 (7-37) is the glycine-extended precursor. Both forms are full agonists at the GLP-1 receptor with comparable potency in receptor assays, and both are cleaved by DPP-4 at the same site. Research catalogs list one or the other; the sequence and mass on the Certificate of Analysis identify which.
Is GLP-1 a protein or a peptide?
GLP-1 is a peptide. At 30 to 31 residues and roughly 3.3 kDa it sits well below the size at which chains are conventionally called proteins, and it does not fold into a stable tertiary structure in solution. The query "GLP1 protein" is common because GLP-1 is derived from a protein precursor (proglucagon) and because "GLP-1 fusion protein" is a distinct research construct discussed below. In solution the peptide is largely unstructured, adopting an alpha-helical conformation in the C-terminal region when bound to the receptor's extracellular domain, as reported in crystal structures of the receptor-ligand complex.
How is GLP-1 produced from proglucagon?
GLP-1 is cleaved from the 160-residue precursor proglucagon by prohormone convertase 1/3 in intestinal L-cells and certain neurons. Proglucagon contains glucagon, GLP-1, and GLP-2 in tandem, and the convertase expressed in a given cell type determines which peptides are released: prohormone convertase 2 in pancreatic alpha cells liberates glucagon, while prohormone convertase 1/3 in L-cells liberates GLP-1 and GLP-2. The GLP-1 segment corresponds to proglucagon residues 72 to 108, and the active 7-37 fragment to residues 78 to 108. The GLP-1 and GIP incretin biology overview on a sister brand covers the secretory physiology in more depth.
Why does DPP-4 cleave GLP-1 and where?
Dipeptidyl peptidase-4 (DPP-4) cleaves GLP-1 between alanine 8 and glutamate 9, removing the N-terminal His-Ala dipeptide and producing GLP-1 (9-36) amide or (9-37), which has negligible agonist activity at the receptor. DPP-4 recognizes a proline or alanine at the second position from the N-terminus, and GLP-1's alanine 8 satisfies that requirement. The consequence is a native half-life in circulation of approximately one to two minutes. This single cleavage site is the reason every long-acting analog substitutes position 8, usually with alpha-aminoisobutyric acid (Aib) or glycine, to block DPP-4 recognition.
What is a GLP-1 fusion protein?
A GLP-1 fusion protein is a research or pharmaceutical construct in which the GLP-1 peptide is genetically fused to a larger carrier protein, most commonly human serum albumin or the Fc region of an immunoglobulin, to extend circulating half-life from minutes to days. Albiglutide (GLP-1 dimer fused to albumin) and dulaglutide (GLP-1 fused to an IgG4 Fc) are the developed examples. These constructs are produced recombinantly rather than by chemical synthesis, have molecular weights in the 60 to 70 kDa range, and are analyzed by protein methods (SDS-PAGE, size-exclusion chromatography) rather than the reverse-phase HPLC used for synthetic peptides. The research-grade GLP-1 in Evo Amino's catalog is the synthetic peptide, not a fusion construct.
How do analog modifications change the molecular weight?
Each design change in a GLP-1 analog adds or removes mass in a predictable way, and the sum is the difference between native GLP-1 at 3337.73 g/mol and, for example, semaglutide at 4113.6 g/mol. Semaglutide substitutes Aib for alanine at position 8 (adding 14 Da for the extra methyl group), substitutes arginine for lysine at position 34 (adding 28 Da), and attaches at lysine 26 a linker consisting of two 8-amino-3,6-dioxaoctanoic acid (AEEA) units and a gamma-glutamate carrying a C18 fatty di-acid. That side chain accounts for most of the roughly 780 Da difference. The fatty di-acid is what drives reversible albumin binding and the multi-day half-life, and the position 8 substitution is what blocks DPP-4. Reading an analog's sequence against native GLP-1 residue by residue is the fastest way to reconcile a listed molecular weight.
What is the difference between GLP-1 and the GLP-1(S) listing?
GLP-1(S) is the catalog label for semaglutide, a synthetic analog, whereas GLP-1 is the native 7-37 peptide. The S suffix identifies semaglutide within the market's GLP-1 numbering scheme, in the same way GLP-1(T) or GLP-2 labels are applied to tirzepatide. The two compounds differ in sequence (semaglutide is 31 residues with three modifications and a lipid side chain), in molecular weight (4113.6 versus 3337.73 g/mol), in CAS number (910463-68-2 versus 106612-94-6), and in stability. The GLP-1 receptor binding assay methods article covers how both are characterized at the receptor.
How is GLP-1 identity confirmed by mass spectrometry?
Identity is confirmed by electrospray ionization mass spectrometry, which for a 3.3 kDa peptide produces a series of multiply charged ions (typically +3 to +6) that deconvolute to a neutral mass compared against the theoretical 3337.73 Da for the 7-37 form. Because the 7-36 amide differs by roughly 40 Da (loss of glycine, gain of the amide), mass spectrometry distinguishes the two forms directly, which reverse-phase HPLC alone may not. Tandem MS fragmentation can additionally confirm sequence order if required. A Certificate of Analysis reporting observed versus theoretical mass has confirmed which GLP-1 form is in the vial.
Does GLP-1 contain any residues that affect storage?
GLP-1 contains a single tryptophan at position 31 and a single methionine-free sequence, so the primary degradation concerns are tryptophan photo-oxidation and the aspartate-containing sequences' tendency toward isomerization over time in solution. The tryptophan is also what gives the peptide measurable absorbance at 280 nm, though purity is conventionally reported at 214 or 220 nm. Lyophilized material is stored at minus 20 degrees Celsius and protected from light. The moisture uptake and glass transition article covers the physical stability of lyophilized peptides in general.
How does GLP-1 compare structurally with the other proglucagon peptides?
GLP-1, GLP-2, and glucagon share a common N-terminal histidine and roughly 50% sequence identity in a conserved core, reflecting their origin in the same precursor. Glucagon is 29 residues, GLP-2 is 33, and GLP-1 (7-37) is 31. Each binds its own class B G-protein-coupled receptor, and the sequence divergence in the C-terminal half is what confers receptor selectivity. Dual and triple agonists engineered in research combine elements of these sequences to engage more than one receptor, which is why their molecular weights fall in the same 4 to 5 kDa range and their analytical profiles resemble one another. The BPC-157 versus GLP-1 comparison situates GLP-1 against a structurally unrelated research peptide.
All compounds referenced in this article are supplied for research purposes only and are not for human use. Nothing here describes or endorses any use of these materials outside laboratory research. These products are not intended to diagnose, treat, cure, or prevent any disease.
Stay in the loop
New compounds, research updates & exclusive subscriber deals.
