What's on the label is the measured result — net peptide mass, not gross powder weight, plus RP-HPLC purity, on a lot-numbered COA for every batch.
Net peptide mass and RP-HPLC purity — a lot-numbered COA for every batch.
Net peptide mass + HPLC purity, per lot.
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ActRIIB-Fc decoy receptor fusion protein · myostatin pathway
PeptideXpo buyer fit
This PeptideXpo page is intentionally positioned for distributors, OEM buyers, and procurement teams comparing ACE-031 (ActRIIB-Fc Fusion) inside a wider peptide catalog. It is not trying to be the deepest single-molecule monograph; the differentiated intent is assortment planning, export-ready documentation, fill-size comparison, and whether this SKU belongs in a broader buyer program.
Overview
ACE-031 is a recombinant soluble fusion protein consisting of the extracellular ligand-binding domain of human Activin Receptor Type IIB (ActRIIB) fused to the Fc region of human IgG1. The fusion functions as a decoy receptor that binds and sequesters myostatin, activin A, and several other TGF-β superfamily ligands that signal through ActRIIB, thereby preventing those ligands from engaging the cell-surface ActRIIB on muscle and other target tissues. The pharmacological consequence is upregulation of muscle mass through loss of myostatin's tonic inhibition of skeletal muscle growth, which is the mechanism behind ACE-031's clinical-development program for Duchenne muscular dystrophy and other muscle-wasting indications (development halted in Phase 2 due to off-target effects). PeptideXpo supplies ACE-031 as a lyophilized recombinant fusion protein at ≥99.0% HPLC purity. As a recombinant glycoprotein fusion, the analytical workflow is biological-product-style rather than synthetic-peptide-style: RP-HPLC for chemical purity, SDS-PAGE under reducing and non-reducing conditions for size and disulfide structure, peptide-mapping for sequence confirmation, glycan-profiling for the Fc and ActRIIB-ECD glycosylation, and bioactivity assay for myostatin-binding affinity. The 1 mg standard fill matches typical research aliquot scales for receptor-pharmacology studies.
Who buys this, and why
Custom-blend buyers are almost always OEM clients building a branded product around a specific ratio of two or more peptides. The development workflow is collaborative: ratio target, analytical method to verify it, stability protocol in the chosen carrier, and packaging selection are all defined in the OEM brief before the first commercial run. Sample-stage volumes are usually 5-10 g of finished blend; commercial MOQ depends on the components.
Primary buyer fit: academic and contract research laboratories.
Specifications
Documentation available on request
Regulatory note
Recombinant fusion protein; no single registered CAS. Confirm expression system, glycosylation profile, and identity per batch COA. Sold for research use only.
Frequently asked questions
ACE-031's Phase 2 development for Duchenne muscular dystrophy was discontinued by Acceleron Pharma in 2011 after observing off-target effects on the broader TGF-β superfamily ligands that ActRIIB also binds, specifically, effects on retinal vasculature and minor nosebleeds suggesting unintended vascular activity. The myostatin-blocking mechanism itself remained biologically promising, but the off-target activin/GDF binding profile of the soluble ActRIIB-Fc decoy was too broad to be acceptable for chronic dosing. Subsequent myostatin-pathway therapeutics (Apitegromab, Bimagrumab) used more selective approaches, antibodies targeting specific TGF-β ligands rather than the receptor decoy, to avoid the off-target profile. ACE-031 remains widely used as a research tool for myostatin-pathway studies despite the discontinued clinical program.
ACE-031 is a soluble receptor-decoy fusion protein (the ActRIIB extracellular domain fused to IgG1 Fc), while myostatin-targeting monoclonal antibodies (Apitegromab, Bimagrumab, Domagrozumab) are conventional IgG antibodies engineered for high-affinity selective binding to specific TGF-β-superfamily ligands. The decoy-receptor approach is broader by design, it sequesters any ligand that binds ActRIIB, which includes myostatin (GDF-8), GDF-11, activin A, and activin B. The selective-antibody approach binds only the targeted ligand and leaves the others free to engage receptors. For research workflows studying the full ActRIIB-ligand axis, ACE-031 is the appropriate tool; for workflows isolating individual ligand contributions, selective antibodies are preferred. The 2011 clinical-program experience suggested that for therapeutic use, the selective approach has a more manageable safety profile.
Published binding-affinity studies of ACE-031 against myostatin show low-nanomolar Kd values, so cellular and biochemical workflows typically use ACE-031 at 10-1000 nM working concentrations (≈0.5-50 μg/mL given the fusion protein's ≈90 kDa size). For dose-response curves the standard experimental design uses a 7-point dilution from 1 nM to 1 μM with half-log spacing. As a recombinant fusion protein, working solutions should be prepared in cell-culture-grade buffer with 0.1% BSA carrier to prevent surface adsorption at low working concentrations; freeze-thaw cycling should be minimized (single-use aliquots at -80 °C is the conservative storage approach for a recombinant protein at research scale).
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