BioLean⁴XR combines two separate molecular structures in one vial: 160mcg of a modified peptide backbone and 5mcg of an albumin-bound Apelin-13 analog. The two peptides are blended, not chemically linked, and each carries its own albumin binder.
The backbone component is studied across three metabolic signaling pathways tied to nutrient sensing and energy balance. The Apelin-13 component adds a fourth pathway.
Apelin-13 is a naturally occurring adipokine, a signaling peptide secreted by fat tissue. Research models link it to glucose uptake, fatty acid oxidation, and mitochondrial biogenesis in muscle tissue [2][3].
Both components use albumin binding to extend their estimated serum stability period. That design choice places BioLean⁴XR in a growing class of research peptides built for longer persistence in laboratory models.
Compound Specifications
| Property |
Value |
| Compound Name |
BioLean⁴XR |
| Compound Class |
Synthetic two-component peptide blend (albumin-bound) |
| Component 1 |
Modified peptide backbone with albumin-binding peptide at position 17 (160mcg) |
| Component 2 |
Albumin-bound Apelin-13 analog (5mcg) |
| Molecular Weight (Component 1) |
7453.26 g/mol |
| Molecular Weight (Component 2) |
4472.76 g/mol |
| Synonyms |
BioLean 4XR, BioLean4XR, BioLean4-XR, BioLean-4XR |
| Source |
Synthetic, controlled peptide synthesis |
| Purity |
≥99% (UHPLC-MS) |
| Appearance |
Lyophilized white powder |
| Solubility |
Soluble in bacteriostatic water |
| Storage |
-20°C, protect from light |
| Vial Size |
2mL |
Storage and Handling
- Store the lyophilized compound at -20°C in the sealed vial, protected from light and moisture.
- Allow the vial to reach room temperature before opening so condensation does not settle on the powder.
- Reconstitute with bacteriostatic water only. Sterile water or saline shortens the solution’s usable life to under 24 hours.
- After reconstitution, store at 2°C to 8°C and use within 28 days. Avoid repeated freeze-thaw cycles.
- Maintain aseptic handling to preserve compound integrity.
Lyophilized Format
This compound ships in lyophilized (freeze-dried) form. Freeze-drying supports long-term storage stability and preserves compound integrity. No fillers are added.
Research Use Disclaimer
BioLean⁴XR is supplied for research use only. It is not a drug, food, cosmetic, or dietary supplement and has not been evaluated by the FDA. By purchasing, the buyer confirms the compound will be used solely for in vitro research.
Frequently Asked Questions
What Is BioLean⁴XR?
BioLean⁴XR is a synthetic research blend of two albumin-bound peptides: 160mcg of a modified peptide backbone and 5mcg of an Apelin-13 analog. It is supplied as a lyophilized powder for laboratory research use only.
What Are the Four Pathways Studied With BioLean⁴XR?
BioLean⁴XR is characterized across four metabolic signaling pathways. Three are linked to the modified backbone and relate to nutrient sensing and energy balance. The fourth is the Apelin-13 signaling pathway studied in glucose uptake and fatty acid oxidation research.
How Does the Albumin Binder in BioLean⁴XR Work?
BioLean⁴XR uses a modified SA21 peptide that binds serum albumin, which is associated with a longer estimated serum stability period in preclinical models. Each of the two components carries its own binder and attaches to a separate albumin molecule.
How Is BioLean⁴XR Stored?
BioLean⁴XR is stored at -20°C as a lyophilized powder in its sealed vial, protected from light. Laboratories reconstitute it with bacteriostatic water, hold it at 2°C to 8°C, use it within 28 days, and avoid repeated freeze-thaw cycles.
How Is the Purity of BioLean⁴XR Verified?
BioLean⁴XR purity is confirmed by UHPLC-MS at ≥99%. Each lot ships with a third-party certificate of analysis.
Research
Research on structurally modified peptide compounds has focused on stability, binding characteristics, and application intervals in preclinical models. Over roughly the past two decades, structural modifications to this compound class have aimed at improving stability, increasing measured binding affinity, and lowering the frequency of observed events in research models.
Lepto3GR carries three structural changes that separate it from comparable research compounds described in the literature.
Modified SA21 Albumin-Binding Peptide
The molecule incorporates a modified SA21 peptide originally developed by Dr. Mark Dennis (Genentech), with the amino acid sequence Ac-RLIEDICLPRWGCLWEDD-NH2. [1]
The original SA21 peptide shows a surface plasmon resonance (SPR) binding affinity of 468 nM to serum albumin (HSA). The modified SA21 peptide used in Lepto3GR records an SPR reading of 10 to 20 nM. [2]
This modification is intended to support higher compound concentrations within target tissues in preclinical models. It is associated with an estimated serum stability period of roughly two weeks, which may support less frequent application intervals and lower per-application concentrations.
Glycine-Serine Linker
A flexible glycine-serine (Gly-Ser) linker (GGSGGSGGSGG) bound to the C-terminus of the SA21 peptide forms the albumin binder used in Lepto3GR’s architecture.
Backbone Attachment and Enzymatic Stability
The glycine-serine linker binds to position #17 of a modified peptide backbone that carries its own amino acid substitutions. These include modification of the second backbone amino acid to alpha-aminoisobutyric acid, intended to protect the compound against cleavage by the dipeptidyl-peptidase 4 (DPP-4) enzyme.
Spacer Configuration
The backbone connects to the albumin binder through a spacer of oligo(ethylene glycol) (OEG) and gamma-glutamic acid (γ-Glu).
This configuration, similar to how fatty acid chains connect to amino acid chains in comparable research compounds, increases hydrophilicity (water solubility) and reduces the steric hindrance associated with albumin-bound fatty acid chains. [3][4]
Research Direction
Further in vitro and preclinical work will be needed to characterize downstream endpoints under study, including binding behavior across target receptors and stability characteristics in research models.
Lepto3GR is intended for laboratory research use only.
References
- Dennis MS. Serum Albumin Binding Peptides for Tumor Targeting. Genentech, Inc.; 2005. US20050287153A1. https://patents.google.com/patent/US20050287153A1
- FBR011 — Novel and Potent G-Protein Coupled Receptor Agonists (URL to be added upon publication)
- Wang S, He W, Xiao C, Tao Y, Wang X. Synthesis of Y-Shaped OEGylated Poly(amino acid)s: The Impact of OEG Architecture. American Chemical Society (ACS); 2019. https://doi.org/10.1021/acs.biomac.9b00026
- Geng C, Wang S, Wang H. Recent Advances in Thermoresponsive OEGylated Poly(amino acid)s. MDPI AG; 2021. https://doi.org/10.3390/polym13111813
Certificate of Analysis (COA)
A Certificate of Analysis (COA) is a document that verifies a compound’s identity, purity and quality through independent laboratory testing. Every compound from BioLongevity Labs is third-party tested, and its COA is published here, so researchers can review the testing record before a compound enters a protocol.
Each COA reports results from third-party laboratory analysis, including:
- Ultra-high-performance liquid chromatography with mass spectrometry (UHPLC-MS) for purity, measured against a 98% or 99% specification depending on the compound
- Mass identification for molecular confirmation and content quantitation
- Endotoxin testing by Limulus amebocyte lysate (LAL) or recombinant Factor C (rFC) assay, depending on the laboratory
- Visual and physical characterization of the finished material
How to Verify a COA Independently
You can check every certificate against the issuing laboratory’s own records, not just the copy hosted here. Verification does not depend on BioLongevity Labs.
- AV Analytics certificates carry a search code. Scan the QR code on the certificate to open the laboratory’s verification page, or enter the search code at avanalytical.com/coa-search to pull the official record.
- BioRegen reports of analysis carry a Report ID and a Validation Key. Scan the QR code on the certificate to open the official record, or quote both identifiers when you contact the laboratory at the address printed on the report.
- SafeCert Labs issued a number of earlier certificates. Each one carries a COA number and the signature of the reporting chemist. Quote that number when you ask the laboratory to confirm it.
- Older certificates from other laboratories list their own verification details on the document.
When a batch is sent to more than one laboratory, each certificate resolves at its own issuing laboratory. A researcher can then check the results against two unrelated sources.
These COAs come from independent certified laboratories, not in-house testing. That gives researchers a verifiable record of molecular integrity for each compound. All compounds are supplied for research use only.
Review the latest COAs for this product below, or browse the full COA library.
