Product details
HGH Fragment 176-191 is the unmodified 16-amino-acid C-terminal fragment of native human growth hormone, corresponding to residues 176-191 of the full-length 191-amino-acid HGH protein. The fragment retains the lipolytic activity associated with this region of native HGH while lacking the central regions that mediate the broader anabolic and IGF-1-stimulating effects of full-length GH. Distinct from the AOD9604 modified analog (which adds an N-terminal tyrosine for iodination-tracking purposes), HGH Fragment 176-191 is the unmodified native sequence and is the form typically used in research workflows studying the lipolytic activity of the HGH C-terminal region in isolation from the rest of the molecule.
Peptuno supplies HGH Fragment 176-191 at ≥99.0% HPLC purity with full identification: CAS 66004-57-7, formula C78H123N23O22S2, MW 1799.1 g/mol, sequence FLRIVQCRSVEGSCGF (note the two cysteines at positions 7 and 14 that can form an intramolecular disulfide bridge under oxidative conditions). The disulfide-bridging behavior is the most common identity-confirmation concern, the reduced and oxidized forms differ by 2 Da and elute at different RP-HPLC retention times. Six standard fill sizes (1-15 mg) cover most research and compounding workflows.
Regulatory note: Easily confused with AOD9604 (the modified analog with N-terminal tyrosine). Confirm exact fragment identity (unmodified vs. AOD9604-modified) via batch COA before order placement; the two are not chemically equivalent.
FAQ
- How do I distinguish HGH Fragment 176-191 from AOD9604 at the analytical level?
- The two molecules differ at the N-terminal residue: native HGH Fragment 176-191 starts with phenylalanine (FLRIVQCRSVEGSCGF), while AOD9604 is Tyr-hGH(177-191) (YLRIVQCRSVEGSCGF), where a tyrosine replaces that N-terminal phenylalanine. Both are 16-amino-acid peptides; HGH Fragment 176-191 has theoretical MW 1799.1 Da and AOD9604 ≈1815 Da. The mass difference is only about +16 Da (the Tyr side chain carries one extra oxygen versus Phe), so the diagnostic mass-spec check at first-time supplier qualification needs adequate resolution. RP-HPLC retention time is also slightly different, the more polar AOD9604 (with the Tyr hydroxyl) elutes slightly differently under typical conditions. Buyers should always confirm the released-batch mass against the expected mass for the form they ordered, since the molecules are easy to confuse but biologically distinct.
- What does the intramolecular disulfide bond in HGH Fragment 176-191 mean for handling?
- The 176-191 sequence (FLRIVQCRSVEGSCGF) contains two cysteines (positions 7 and 14 within the fragment) that can form an intramolecular disulfide bond. Under reducing conditions during synthesis, the cysteines are free thiols; under oxidative conditions during storage and reconstitution, they can form the disulfide bridge. The reduced and oxidized forms differ by 2 Da in mass and elute at different RP-HPLC retention times. Most published research uses the oxidized (disulfide-bridged) form, which is the more stable solid-state form. Buyers should confirm with the COA which form the batch represents, if your research protocol requires a specific form, this matters operationally.
Certificate of Analysis (COA)
The per-lot COA for this product will appear here.