What is PEG MGF?
PEG MGF is the PEGylated synthetic form of Mechano Growth Factor (MGF), studied in research as a structurally modified analog of a locally expressed IGF-1 splice variant. It is catalogued under CAS number 108174-48-7. The core peptide carries a molecular formula of C₁₂₁H₂₀₀N₄₂O₃₉ and a molecular weight of 2867.2 g/mol; the polyethylene glycol chain adds additional mass that varies with PEG chain length, which is why the compound is catalogued with the core peptide molecular weight and a parenthetical notation indicating PEG-dependent variation. The compound is supplied as a lyophilized powder and is intended solely for laboratory research purposes, not for human use.
Within growth factor peptide research, PEG MGF occupies a defined position: it is studied as a structurally stabilized form of the E-domain peptide associated with the IGF-1Ec splice variant, with PEGylation studied for its effect on circulating stability in model systems. Understanding the compound requires understanding its parent molecule — the natural splice variant from which the MGF E-domain sequence is derived — and what the PEG modification adds to the research profile.
What is the relationship between PEG MGF, MGF, and IGF-1?
MGF is not a synthetic construct — it is a naturally occurring product of the IGF-1 gene. The IGF-1 gene undergoes alternative splicing to produce multiple protein isoforms. The systemic isoform, IGF-1Ea (often referred to as liver-type IGF-1), is the endocrine form that circulates in plasma and is extensively studied for its binding to the type 1 IGF receptor (IGF-1R). The locally expressed isoform, IGF-1Ec — referred to as Mechano Growth Factor in the research literature — is produced by an alternative splicing event that incorporates a unique exon-encoded E-domain at the C-terminus. This distinct E-domain is the structural feature that differentiates MGF from systemic IGF-1.
The research interest in MGF stems from its different expression pattern: it is studied as a locally expressed, mechanosensitive isoform rather than as a systemic hormone analog. Its expression in studied model systems is upregulated in response to mechanical stimulation and cellular stress signals, which is why it appears extensively in the tissue-repair and mechano-signaling literature. MGF and systemic IGF-1 share the same IGF-1 gene origin and the same N-terminal IGF-1 core domain responsible for IGF-1R binding, but their C-terminal E-domains differ, and their studied expression patterns differ accordingly.
The synthetic peptide known as MGF — and by extension, PEG MGF — corresponds to the unique C-terminal E-domain of IGF-1Ec rather than the full-length protein. This focused synthetic form is what researchers use to study E-domain-specific signaling properties separately from the IGF-1R-mediated effects of the shared IGF-1 core domain.
What is the molecular structure of PEG MGF?
The core peptide of PEG MGF has a molecular weight of 2867.2 g/mol and the molecular formula C₁₂₁H₂₀₀N₄₂O₃₉. This corresponds to the synthetic form of the MGF E-domain — the region unique to the IGF-1Ec splice variant. It is a relatively compact peptide, substantially smaller than full-length IGF-1 protein and smaller than most GHRH analogs, reflecting the fact that it represents only the C-terminal E-domain rather than the complete growth factor sequence.
The PEGylated form is the core peptide with a polyethylene glycol chain attached, typically through maleimide-thiol or N-hydroxysuccinimide ester chemistry at a defined reactive site. The PEG chain contributes additional molecular weight that varies by chain length; this is why the compound is catalogued with the core peptide MW and an explicit note about PEG chain variation. The attachment point and chain length determine the hydrodynamic profile researchers are working with.
PEG MGF is produced through chemical synthesis of the E-domain peptide followed by PEG conjugation, then HPLC purification. The compound is supplied at a purity specification of 98.9% and characterized in lyophilized form as a white to off-white powder. As with other peptide conjugates, structural integrity is sensitive to temperature fluctuation, oxidation, and moisture throughout storage and handling.
What does PEGylation do to the core MGF peptide?
PEGylation — the covalent attachment of polyethylene glycol to a peptide — is a well-characterized structural strategy studied for modifying circulating stability and renal clearance rate in peptide research. Unmodified MGF E-domain peptide has a short half-life in aqueous and plasma environments, attributed primarily to rapid renal filtration (a consequence of its low molecular weight as a small peptide) and proteolytic degradation by plasma proteases.
PEGylation modifies both clearance mechanisms. The attached PEG chain increases the hydrodynamic radius of the compound. An increased hydrodynamic radius delays glomerular filtration — the primary clearance route for small peptides — because the kidney's filtration threshold is determined by effective molecular size rather than molecular weight alone. The bulky, hydrophilic PEG chain also creates steric shielding around the peptide backbone, which reduces the rate of proteolytic cleavage.
For research applications, PEGylation is studied as a means to extend the temporal window of MGF E-domain exposure in the experimental system. Comparing unmodified MGF E-domain peptide with PEG MGF in the same model characterizes the contribution of circulating half-life to the observed signaling profile — a standard approach in peptide pharmacology research when kinetic duration is a variable of interest. AminoLine does not make therapeutic or outcome claims regarding PEG MGF; the compound is studied at the level of receptor binding and cellular signaling mechanism in laboratory models.
What receptors and signaling pathways does PEG MGF engage in research?
Research on PEG MGF addresses two distinct signaling questions corresponding to the two structural regions of the full-length MGF protein.
The first involves IGF-1R binding via the shared IGF-1 core domain. Because the MGF protein retains the same IGF-1 core domain as systemic IGF-1Ea, the full-length protein binds the type 1 IGF receptor. Research examining this aspect studies IGF-1R activation, the downstream PI3K/Akt and MAPK/ERK signaling cascades associated with IGF-1R engagement, and how locally expressed MGF interacts with the systemic IGF-1 signaling axis. The synthetic MGF E-domain peptide — the compound catalogued as PEG MGF — corresponds to only the E-domain portion, not the IGF-1R-binding core domain.
The second question, which is specific to the E-domain peptide, concerns whether the MGF E-domain engages receptors independently. Published research has examined E-domain-specific activity in cell migration and satellite cell activation assays that cannot be fully attributed to IGF-1R binding by the core domain, suggesting an independent receptor interaction or intracellular signaling contribution from the E-domain peptide itself. This mechanism remains an active area of characterization in the literature. PEG MGF, with its extended stability relative to the unmodified E-domain peptide, provides a longer observation window for studying this isolated E-domain signaling in in vitro model systems.
Concentration-response characterization in E-domain-specific assays provides the parameters used to position PEG MGF relative to other IGF-1 axis research compounds.
How is PEG MGF studied in relation to IGF-1 LR3?
PEG MGF and IGF-1 LR3 appear together in the healing and growth factor compound category, and both engage the IGF-1 signaling axis, but they are studied for different aspects of that system. The distinction is important for experimental design.
IGF-1 LR3 is a long-arginine-3 analog of full-length IGF-1 studied for its reduced binding affinity for IGF-binding proteins (IGFBPs). Native systemic IGF-1 in circulation is predominantly bound to IGFBPs, which modulate its bioavailability and receptor access. The Arg substitution at position 3 in IGF-1 LR3 substantially reduces IGFBP binding affinity, and the compound is studied in models where the contribution of IGFBP regulation to IGF-1R signaling is the variable of interest.
PEG MGF is studied for E-domain-specific signaling — signaling attributable to the unique MGF C-terminal region that is absent from systemic IGF-1 — rather than for IGFBP-modulated IGF-1R activity. Researchers characterizing isolated IGF-1R engagement with minimal IGFBP interference use IGF-1 LR3. Researchers studying the MGF E-domain specifically, or the mechanosensitive splice variant signaling axis, use PEG MGF.
Treating the two as interchangeable substitutes would misrepresent their different mechanistic research questions. Both are available in the AminoLine catalog at all compounds.
How should PEG MGF be stored and handled for research?
PEG MGF is supplied as a lyophilized powder and is stored at −20°C to preserve structural integrity. The PEG chain modifies the circulating half-life profile in model systems; it does not eliminate the compound's sensitivity to temperature, oxidation, or moisture in the lyophilized state. Repeated freeze-thaw cycles, elevated humidity, and temperature excursions can compromise both the peptide backbone and the PEG conjugation linkage.
Standard research handling practices apply: maintain cold storage, minimize freeze-thaw exposure, keep the lyophilized material sealed against moisture. Cold-chain shipping protects the same integrity during transit — a compound characterized at 98.9% purity at manufacture can lose that specification through thermal exposure en route. AminoLine ships all peptide compounds with cold-chain packaging as standard.
This article does not include preparation or reconstitution instructions. Handling protocols are the researcher's responsibility and should be determined by experimental requirements and applicable regulations.
How does AminoLine source PEG MGF?
AminoLine supplies PEG MGF as a research-grade compound characterized to a purity specification of 98.9% by HPLC, with mass spectrometry identity confirmation of the core peptide. Every order ships with a batch-specific Certificate of Analysis, and all shipments are cold-chain packaged as standard. Operations are US-based.
Researchers can review specifications, available sizes, and pricing on the PEG MGF product page. Related compounds in the growth factor and healing research category — including IGF-1 LR3 — are available at all compounds. All material is for laboratory research use only and is not for human use.
This compound is a research chemical intended for laboratory and scientific research purposes only. It is not a drug, supplement, or food, and is not intended to diagnose, treat, cure, or prevent any disease. AminoLine does not sell products intended for human use. Researchers are responsible for compliance with all applicable local, state, and federal regulations.