PEG-MGF 2mg

What is PEG-MGF ?

PEG-MGF is a PEGylated form of mechano growth factor, the IGF-1Ec splice-variant peptide expressed in muscle tissue in response to mechanical load. PEGylation of the 24-residue sequence slows clearance relative to the unmodified peptide, and research has examined both forms in models of muscle cell proliferation and satellite cell activation.

The peptide is the 24-residue E domain of the IGF-1Ec splice variant: Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-His-Lys (YQPPSTNKNTKSQRRKGSTFEEHK). The batch certificate lists the conjugate at roughly 9.8 kDa. As a polymer conjugate it has no CAS number. Yang, Alnaqeeb, Simpson and Goldspink (J Muscle Res Cell Motil, 1996) cloned the splice variant from stretched rabbit muscle.

In the literature, MGF can mean the splice-variant mRNA or the synthetic E-domain peptide (Matheny, Nindl and Adamo, Endocrinology, 2010). PEG-MGF, also written pegylated MGF, is the E-domain peptide with a PEG chain attached. Each vial holds 2mg of white lyophilised powder.

PEG-MGF Research Applications

• Myoblast proliferation : Yang and Goldspink (FEBS Lett, 2002) reported that the E domain increased myoblast proliferation and inhibited terminal differentiation, unlike mature IGF-1.
• Satellite cells : Hill and Goldspink (J Physiol, 2003) found the MGF splice form expressed as an early pulse after local muscle damage, alongside satellite cell activation.
• Human muscle cells : Kandalla and colleagues (Mech Ageing Dev, 2011) reported more proliferation and later senescence in cultures from neonatal and young adult donors, but not from old adults.
• Negative data : Fornaro and colleagues (Am J Physiol Endocrinol Metab, 2014) found no effect at up to 500 ng/ml. They tested C2C12 cells, primary human myoblasts and primary mouse muscle stem cells.

All of these studies used the unmodified E peptide. No peer-reviewed paper has tested the PEGylated form, so its behaviour in an assay is an extrapolation. Other published models use progenitor cells from normal, dystrophic and ALS muscle (Ates et al., FEBS Lett, 2007). Mills and colleagues (Am J Transplant, 2007) studied engraftment of human myogenic precursor cells in mice. There are no clinical trials.

PEG-MGF vs MGF

Both contain the same 24-residue E-domain peptide. MGF is the unmodified peptide, the molecule used in every published study cited here. PEG-MGF adds polyethylene glycol, which raises the mass to roughly 9.8 kDa. The polymer also changes how the conjugate behaves in the lab. It runs at a higher apparent mass on size-exclusion columns and can interfere with antibody-based detection. MGF is the choice for replicating published work. With PEG-MGF, count the PEG chain as an extra variable to control.

Research Overview

PEG-MGF is the PEGylated form of mechano growth factor (MGF), the 24-residue C-terminal E-domain peptide of the IGF-1Ec splice variant of insulin-like growth factor 1. The underlying peptide sequence is Tyr-Gln-Pro-Pro-Ser-Thr-Asn-Lys-Asn-Thr-Lys-Ser-Gln-Arg-Arg-Lys-Gly-Ser-Thr-Phe-Glu-Glu-His-Lys, written YQPPSTNKNTKSQRRKGSTFEEHK, with a molecular weight of approximately 2866 g/mol unmodified and approximately 9.8 kDa in the PEGylated form supplied here. The splice variant was first cloned from mechanically stretched rabbit muscle by Yang, Alnaqeeb, Simpson and Goldspink (J Muscle Res Cell Motil, 1996), and its expression in muscle in response to mechanical load is what the mechano growth factor name records. PEG-MGF is a conjugate rather than a discrete small molecule and carries no CAS registry number on this listing.

The splice biology matters because it defines what the molecule is. The IGF-1Ec transcript carries a 49-base insert in the human sequence, and because the insert is not a multiple of three, the reading frame shifts and the C-terminal E domain is encoded in a different frame from the systemic IGF-1Ea isoform. It is that E-domain peptide, rather than the mature IGF-1 protein, that the early literature connected to muscle repair: the peptide drives myoblast proliferation while blocking differentiation (Yang and Goldspink, FEBS Lett, 2002), appears as an early pulse after local muscle damage in association with satellite cell activation (Hill and Goldspink, J Physiol, 2003), and increased progenitor cell numbers in cultures from normal, dystrophic and ALS muscle (Ates et al., FEBS Lett, 2007). Goldspink's review (Physiology, 2005) frames MGF as the local, damage-triggered isoform, with splicing switching toward IGF-1Ea as repair proceeds.

The PEGylation step is a pharmacokinetic modification, not a change to the peptide chemistry. The unmodified E peptide is cleared from circulation within minutes, so conjugation of polyethylene glycol, raising the mass to roughly 9.8 kDa, is designed to slow clearance through increased hydrodynamic radius, reduced renal filtration and shielding from proteases, the standard logic of the field reviewed by Harris and Chess (Nat Rev Drug Discov, 2003). In primary human muscle cell culture, the unmodified E peptide increased proliferation and delayed senescence in cultures from neonatal and young adult donors but not old adult muscle (Kandalla et al., Mech Ageing Dev, 2011), and in a mouse transplantation model it improved myogenic precursor cell engraftment (Mills et al., Am J Transplant, 2007).

It is worth being direct about the state of the evidence. The primary literature concerns the unmodified E-domain peptide, and the PEGylated form itself has no dedicated peer-reviewed publications, so its behaviour in any assay is an extrapolation from the unmodified molecule and from general PEGylation pharmacology. The founding in-vitro claims have also been challenged directly: a study conducted at two pharmaceutical companies found no effect of the MGF C-terminal peptide, at concentrations up to 500 ng/ml, on the proliferation or differentiation of C2C12 cells, primary human myoblasts or primary mouse muscle stem cells, and concluded that the physiological role of MGF itself should be questioned (Fornaro et al., Am J Physiol Endocrinol Metab, 2014). Human evidence is thin to absent, and the field's own review literature describes MGF as a putative repair factor (Matheny, Nindl and Adamo, Endocrinology, 2010). PEG-MGF is not an approved medicine in any jurisdiction and is supplied as lyophilised powder, supplier-tested at 99.77% purity with batch UKPL-9506, with the certificate published on this page and independent third-party verification pending, for in-vitro laboratory research only.

Storage and Reconstitution

Move vials to the freezer on arrival and keep them dark and dry. Freeze reconstituted stock in single-use aliquots and thaw each one once. PEG conjugates still aggregate under repeated freeze-thaw. Keep the solution away from oxidising agents and organic solvents.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

• The 24-residue E-domain sequence contains no methionine, cysteine or tryptophan, so there are no oxidation-prone residues or disulfides to manage; the handling considerations are the PEG moiety (hydrophilic, altered behaviour on filters and gels) and sterility.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation (Yang and Goldspink, FEBS Lett, 2002)
• Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage (Hill and Goldspink, J Physiol, 2003)
• Mechano Growth Factor E peptide (MGF-E), derived from an isoform of IGF-1, activates human muscle progenitor cells and induces an increase in their fusion potential at different ages (Kandalla et al., Mech Ageing Dev, 2011)
• Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells (Fornaro et al., Am J Physiol Endocrinol Metab, 2014)

Published research on PEG-MGF is indexed on PubMed. See our full UK buyer's guide for PEG-MGF.