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D-retro-inverso FOXO4 / p53 interaction blocker · senolytic peptide
Research documentation
Ask sales for the FOXO4-DRI batch COA and the analytical evidence needed to qualify the material for your study. Confirm the available purity and identity records, lot continuity, handling information, and method requirements before ordering.
Overview
FOXO4-DRI (also FOXO4-D-Retro-Inverso, FOX04, FOX04-DRI) is a senolytic peptide engineered to break the intracellular FOXO4-p53 interaction that keeps senescent cells alive. It comprises 46 residues in a D-retro-inverso format, joining a 34-residue FOXO4 segment that engages p53 to a 12-residue TAT-derived cell-penetrating shuttle. Reversing the sequence while substituting D-amino acids reproduces the binding-surface geometry of the natural L-peptide yet confers strong resistance to proteolysis, markedly prolonging intracellular lifetime. Reported by Peter de Keizer's laboratory at the University of Groningen in 2017, it went on to become one of the most cited senolytic peptides, shown to selectively drive apoptosis in senescent cells across a range of aging and disease models. Lyochem supplies FOXO4-DRI as a lyophilized reference standard to a ≥99.0% HPLC purity specification. Building a full D-amino-acid chain is more exacting than standard L-peptide assembly, and the D-Fmoc building blocks are considerably pricier than their L counterparts, which is the main reason the per-mg cost runs above comparably sized L-peptides. Every released lot comes with its batch COA reporting RP-HPLC purity and mass-spectrometric molecular-weight confirmation, with LC-MS/MS sequence verification available on request. Fill sizes of 2 mg and 10 mg align with common senescence-research aliquot scales.
Applications & buyer fit
Longevity-class peptides — Epithalon, FoxO4-DRI, PNC-27 — ship to research labs studying telomere maintenance, senescence-clearance, and tumour-suppressor pathways. The chemistry is well-behaved but solution stability matters: Epithalon and FoxO4-DRI both prefer chelator-free water and storage at −20 °C protected from light. For chronic-exposure in vivo work, request bacterial-endotoxin testing on the specific lot at quote stage.
Academic Laboratories
Universities, medical schools, and government research institutes qualifying a reference standard for a method-development or in vivo workflow.
Every lot has its own batch-specific CoA — HPLC purity and MS identity, plus any analytical scope agreed at quote stage — tied to the exact lot you receive.
Review a representative batch CoA before you order, so you can confirm the packet matches what your method or sponsor audit needs.
Supplied strictly as a research reagent to research institutions — not a finished dosage form and not for human administration. Buyer qualification runs at the inquiry stage.
Specifications
Documentation available on request
Regulatory note
Sold for Research Use Only under the receiving laboratory's institutional and jurisdictional regulations. Not a finished dosage form, not labelled for human administration, not for in-vitro diagnostic use. Chronic-exposure in vivo work should specify the additional analytical readouts needed (endotoxin, microbial limits, stability series) at quote stage.
Selected literature
Frequently asked questions
Standard RP-HPLC and ESI-MS confirm net composition and mass, but because a DRI peptide is a stereochemical construct, mass alone cannot prove the D-amino-acid identity or reversed sequence. Chiral analysis, typically amino-acid analysis after acid hydrolysis with chiral derivatization (or chiral GC/LC), verifies that residues are the intended D-configuration rather than L-contaminants. LC-MS/MS sequencing confirms the residue order corresponding to the retro sequence. Diastereomeric or epimerized impurities can co-elute closely, so a reference lot should report the RP-HPLC purity, the confirmed intact mass, and a statement supporting the D-retro-inverso stereochemistry.
The D-amino-acid backbone is not cleaved by the proteases that act specifically on L-peptide bonds, so FOXO4-DRI resists degradation in serum, lysate, and cell-culture matrices where a natural L-peptide would be consumed within minutes. For reference-standard work this is an advantage: the compound persists long enough to serve as a stable internal or external standard in LC-MS/MS interaction assays, and quantitation is less confounded by matrix-driven turnover. Buyers should still confirm the reconstitution solvent and purity on the COA, since chemical stability against proteases does not exempt the peptide from oxidation or aggregation during improper storage.