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peptides

product-1400-1400

Products Description

### ACE-031 peptide: a systematic review

ACE-031 (Activin Receptor Type IIB Fusion Protein) is a recombinant fusion protein designed by genetic engineering technology to regulate muscle growth and metabolism. Its core mechanism is to promote skeletal muscle hypertrophy and inhibit muscle atrophy by blocking the transforming growth factor-β (TGF-β) superfamily signaling pathway (such as activin and myostatin). This article will systematically explore the classification, physicochemical properties, advantages and potential applications of ACE-031.

### 1. Structure and mechanism of action of ACE-031

ACE-031 is composed of the extracellular domain of human activin receptor IIB (ActRIIB) fused with the Fc fragment of immunoglobulin G (IgG). This design gives it the following characteristics:

1. **High affinity binding**: The ActRIIB domain can specifically bind to TGF-β family ligands (such as activin A, myostatin).

2. **Extended half-life**: IgG Fc fragments significantly extend the half-life in vivo through a circulating mechanism mediated by the neonatal Fc receptor (FcRn).

3. **Signal pathway inhibition**: By competitively binding to ligands, blocking their interaction with cell membrane receptors, inhibiting SMAD2/3 signaling, and thus promoting muscle anabolism.

### 2. Classification and derivatives of ACE-031

According to structural modification and functional optimization, ACE-031 and its analogs can be divided into the following categories:

#### **1. Basic ACE-031**

- **Structure**: Original fusion protein, containing ActRIIB extracellular domain and human IgG1 Fc segment.

- **Advantages**:

- High biological activity: It can significantly increase muscle mass and strength in animal models.

- Low immunogenicity: Humanized design reduces the risk of antibody production.

- **Physical and chemical properties**:

- Molecular weight: about 110 kDa (55 kDa in monomeric form, usually present as dimers).

- Solubility: Soluble in neutral buffer (such as PBS), with optimal stability at pH 7.4.

- Color: Lyophilized powder is white or off-white, and becomes a transparent colorless liquid after reconstitution.

- **Application**: Early clinical studies have used it to treat Duchenne muscular dystrophy (DMD) and cancer cachexia.

#### **2. PEGylated ACE-031**

- **Structure**: Polyethylene glycol (PEG) chains are coupled to the base type to enhance pharmacokinetic properties.

- **Advantages**:

- Extended half-life: PEGylation reduces renal clearance and extends the half-life to 7-10 days.

- Reduced dosing frequency: Subcutaneous injection once a week can maintain effective concentrations.

- **Physicochemical properties**:

- Molecular weight: Varies with PEG chain length (usually increases by 20-40 kDa).

- Solubility: The degree of PEGylation needs to be optimized to avoid aggregation.

- Color: Lyophilized powder may be slightly yellowish due to the type of PEG, and the solution remains clear.

#### **3. Mutant variants (such as ACE-031-V1)**

- **Structure**: Optimize stability and activity through point mutations (such as N-linked glycosylation site modification).

- **Advantages**:

- Enhanced thermal stability: After mutation, it can be stored at 4°C for a longer time, reducing cold chain dependence.

- Improved potency: The binding affinity of some variants is increased by 2-3 times.

- **Physical and chemical properties**:

- Isoelectric point (pI): It may shift from 7.8 to 8.2 due to mutation.

- Color: Consistent with the basic type, white lyophilized powder.

#### **4. Peptide fragment mimics**

- **Structure**: Small molecule peptides designed based on the ActRIIB binding domain (about 15-30 amino acids).

- **Advantages**:

- Oral potential: Some cyclic peptides can resist protease degradation.

- Low cost: Chemical synthesis replaces recombinant expression.

- **Physical and chemical properties**:

- Molecular weight: 1.5-3.5 kDa.

- Solubility: Some hydrophobic peptides require DMSO to help dissolve.

- Color: Usually white powder, some peptides containing aromatic amino acids are light yellow.

### 3. Core advantages of ACE-031

1. **Target specificity**: Precise inhibition of myostatin (Myostatin), avoiding the side effects of broad-spectrum TGF-β inhibition.

2. **Significant efficacy**: In animal models, muscle mass can be increased by 20-40%.

3. **Wide indications**: Covering hereditary myopathy (such as DMD), age-related sarcopenia, cancer cachexia, etc.

4. **Formulation flexibility**: Can be developed into lyophilized powder injection, prefilled syringe or long-acting sustained-release dosage form.

### 4. In-depth analysis of physical and chemical properties

1. **Stability**:

- Thermal stability: The activity of the basic type decreases by <10% within 72 hours at 25°C, and the mutant can tolerate 37°C for 48 hours.

- Photosensitivity: freeze-dried powder needs to be stored away from light, as light may cause oxidation of the Fc segment.

2. **Spectral characteristics**:

- UV absorption peak: 280 nm (mainly from tryptophan and tyrosine).

- Fluorescence characteristics: excitation wavelength 280 nm, emission peak 340 nm (for purity detection).

3. **Analytical methods**:

- SDS-PAGE: verify dimer integrity (approximately 110 kDa band).

- Mass spectrometry (LC-MS): confirm molecular weight and glycosylation modification.

- Circular dichroism (CD): monitor secondary structure (β-folding ratio> 60%).

### 5. Clinical application and challenges

#### **1. Clinical trial progress**

- **DMD Phase II trial** (NCT01099761):

- Results: 6 months of treatment increased lean body weight by 1.2 kg (vs 0.3 kg in the placebo group).

- Reason for termination: increased risk of bleeding (associated with angiogenesis inhibition).

- **Cancer cachexia**: Did not enter Phase III due to insufficient efficacy.

#### **2. Main challenges**

- **Safety**: TGF-β pathway is widely involved in tissue repair, which may lead to fibrosis or cardiovascular side effects.

- **Cost**: Recombinant protein production is expensive (about $5000/g).

- **Competition from alternative therapies**: Such as monoclonal antibodies targeting Myostatin (Stamulumab) or gene therapy.

### 6. Future development direction

1. **Tissue-specific delivery system**: Use nanoparticles to target muscle tissue and reduce systemic exposure.

2. **Bifunctional fusion protein**: Combined with IGF-1 or IL-15 receptor agonists, synergistically promote muscle regeneration.

3. **Oral formulation development**: Research on penetration enhancers based on peptide mimetics.

### Conclusion

ACE-031, as a representative of muscle metabolism regulators, has demonstrated the potential for targeted treatment of muscle wasting diseases. Although clinical transformation faces challenges, its derivatives are expected to achieve breakthrough applications in the next decade through structural optimization and delivery technology innovation. Researchers need to find a balance between efficacy, safety and cost to promote such therapies to benefit a wider patient population.