5-Deoxyflavin (5-Deazaflavin) — Flavin Cofactor Analog, N5→C5 Substitution, ≥98% HPLC, Research Grade Supplier
A synthetic flavin analog in which the N5 ring nitrogen is replaced by carbon (C5), fundamentally altering redox behavior by abolishing semiquinone radical formation and enforcing concerted two-electron hydride transfer. An indispensable mechanistic probe for distinguishing hydride transfer from single-electron transfer (SET) pathways in flavoenzyme catalysis. Available from UPOR Biotech with ≥98.0% HPLC purity, ISO 9001:2015 and c-GMP quality assurance, comprehensive CoA documentation, and global shipping.
Request a QuoteProduct Overview
5-Deoxyflavin (5-deazaflavin, CAS 26908-38-3), systematically named pyrimido[4,5-b]quinoline-2,4(1H,3H)-dione, is a synthetic analog of the naturally occurring flavin cofactors (FMN, FAD) in which the N5 pyrazine nitrogen atom of the isoalloxazine ring system is replaced by a carbon atom bearing a hydrogen. This deceptively simple atomic substitution — nitrogen to carbon at position 5 — produces profound alterations in redox chemistry, electronic structure, and photophysical properties that have made 5-deazaflavin one of the most widely employed chemical probes in flavoenzyme mechanistic enzymology.
In native flavins, the N5 position serves as the primary locus of electron density during one-electron reduction to the semiquinone radical. Substituting this nitrogen with carbon eliminates the lone pair and disrupts the π-delocalization pathway essential for radical stabilization. Consequently, 5-deazaflavin cannot form a stable semiquinone radical intermediate under any conditions — electrochemical, photochemical, or enzymatic. All redox chemistry proceeds exclusively through concerted two-electron hydride transfer, making the compound a definitive diagnostic tool for distinguishing hydride (H⁻) transfer from single-electron transfer (SET) mechanisms in flavoprotein active sites.
Beyond its mechanistic utility, 5-deazaflavin exhibits a distinctive yellow to yellow-orange coloration with a UV-Vis absorption maximum at approximately 400-420 nm — significantly shifted relative to native flavins — enabling facile spectroscopic tracking of binding, reduction, and reoxidation events. The compound has been instrumental in elucidating the catalytic cycles of glucose oxidase, D-amino acid oxidase, glutathione reductase, thioredoxin reductase, and numerous other flavin-dependent oxidoreductases. UPOR Biotech supplies 5-deoxyflavin at ≥98.0% purity by HPLC, manufactured under ISO 9001:2015 and c-GMP quality management systems, with full Certificate of Analysis (CoA), MS, and NMR documentation provided with every shipment.
Research Use Only (RUO) — not for human diagnostic or therapeutic use. This product is intended for laboratory research and development purposes only.
N5→C5 Substitution — The Single-Atom Switch That Transforms Flavin Redox Chemistry
Replacing the N5 pyrazine nitrogen with carbon abolishes semiquinone radical formation entirely and enforces obligatory two-electron hydride transfer. This makes 5-deazaflavin the definitive control experiment for distinguishing hydride (H⁻) transfer from single-electron transfer (SET) pathways — a question at the heart of flavoenzyme mechanism. No other commercially available flavin analog provides this level of mechanistic discrimination. UPOR Biotech supplies the compound with ≥98.0% HPLC purity, full CoA, and ISO 9001:2015 / c-GMP quality assurance for reproducible, publishable results.
Product Specifications
| Property | Specification |
|---|---|
| CAS Number | 26908-38-3 |
| Molecular Formula | C₁₂H₁₀N₂O₂ |
| Molecular Weight | 214.22 g/mol |
| IUPAC Name | Pyrimido[4,5-b]quinoline-2,4(1H,3H)-dione |
| Common Name | 5-Deoxyflavin |
| Synonyms | 5-Deazaflavin, 5-Deoxyisoalloxazine, Deazaflavin |
| Compound Type | Flavin cofactor analog — N5→C5 substitution (Type C, Non-HA) |
| Appearance | Yellow to yellow-orange crystalline powder |
| Melting Point | >300 °C |
| UV-Vis Absorption (λmax) | ~400–420 nm |
| Assay (HPLC) | ≥98.0% |
| Purity Determination Method | HPLC (reverse-phase, UV detection at 254 nm and 405 nm) |
| Identity Confirmation | ¹H NMR (400 MHz), ESI-MS |
| Solubility — Water | Sparingly soluble |
| Solubility — DMSO | Soluble (recommended for stock solutions) |
| Solubility — DMF | Soluble |
| Solubility — Methanol | Soluble |
| Solubility — Ethanol | Slightly soluble |
| Loss on Drying | ≤1.0% |
| Heavy Metals | ≤20 ppm |
| Residue on Ignition | ≤0.5% |
| Residual Solvents | Meets USP <467> limits |
| Storage Temperature | −20 °C, protected from light and moisture |
| Packaging | Amber glass vial under inert atmosphere (Ar/N₂) |
| Shipping Condition | Ambient temperature (short-term) |
| Shelf Life | 2 years from date of QC release |
| Grade | Research Grade (RUO) |
| Certifications | ISO 9001:2015, c-GMP |
| QC Documentation | Certificate of Analysis (CoA), HPLC, NMR, MS, SDS |
| Country of Origin | China |
Key Features and Mechanistic Significance
N5→C5 Substitution — Hydride vs SET Mechanistic Probe
The replacement of the N5 pyrazine nitrogen with a carbon atom eliminates the lone pair essential for semiquinone radical stabilization, forcing all redox chemistry through a concerted two-electron hydride transfer pathway. This makes 5-deoxyflavin the definitive negative control in experiments designed to determine whether a given flavoenzyme operates via one-electron radical (SET) or two-electron hydride (H⁻) mechanism. When a reaction proceeds with native flavin but not with 5-deazaflavin, a radical pathway is strongly implicated.
Mechanistic ProbeAltered Redox Chemistry — Weaker Oxidant for Biocatalysis Research
The N5→C5 substitution raises the two-electron reduction potential by approximately 100–150 mV relative to native flavin, converting the cofactor into a weaker oxidant. This shift enables selective reduction of high-potential substrates without off-target oxidation events, making 5-deazaflavin a valuable tool in biocatalysis research where chemoselectivity is critical. The altered redox potential also allows trapping of reaction intermediates that are too fleeting to characterize with native flavin cofactors.
Altered RedoxDistinctive Yellow-Orange Chromophore for Spectroscopic Tracking
The carbon-for-nitrogen substitution shifts the UV-Vis absorption maximum to approximately 400–420 nm — a distinctive yellow-orange chromophore that is well separated from protein absorbance (280 nm) and from most common biochemical chromophores. This spectral window enables clean, interference-free monitoring of cofactor binding, reduction, and reoxidation kinetics by stopped-flow or steady-state spectroscopy. The photophysical properties also support photoexcitation studies for time-resolved mechanistic investigations.
Spectroscopic ToolEssential Tool for Flavoenzyme Mechanistic Enzymology
Since its introduction by Hemmerich and colleagues, 5-deazaflavin has been cited in thousands of publications spanning the mechanistic characterization of glucose oxidase, D-amino acid oxidase, monoamine oxidase, glutathione reductase, thioredoxin reductase, cytochrome P450 reductase, and numerous other flavin-dependent enzymes. UPOR Biotech ensures batch-to-batch consistency with ≥98.0% HPLC purity, full QC traceability, ISO 9001:2015 manufacturing, and c-GMP quality systems — so your mechanistic conclusions are built on a reliable chemical foundation.
Research EssentialResearch Applications
Flavoenzyme Mechanistic Studies
Determine whether flavin-dependent oxidoreductases operate via radical SET or hydride transfer pathways by comparing activity with native flavin versus 5-deazaflavin. Loss of activity with the analog implicates a radical mechanism.
Cofactor Analog Research
Reconstitute apoenzymes with 5-deazaflavin to generate modified holoenzymes for structure-function studies. Used in X-ray crystallography and cryo-EM to trap specific redox states.
Electron Transfer Studies
Investigate biological electron transfer chains by replacing native flavin with 5-deazaflavin to block radical propagation steps, enabling isolation and characterization of individual electron transfer events.
Hydride vs SET Probes
Employ 5-deazaflavin as a diagnostic reagent to distinguish concerted hydride transfer from sequential electron-proton-electron transfer in organic and bioinorganic model systems.
Photochemical Research
Utilize the red-shifted absorption and altered excited-state properties of 5-deazaflavin for photoinduced electron transfer studies, time-resolved spectroscopy, and photoredox catalysis investigations.
Enzyme Inhibitor Design
Exploit the altered redox potential and binding characteristics of 5-deazaflavin as a scaffold for designing mechanism-based or competitive inhibitors targeting flavin-dependent enzymes of therapeutic interest.
Frequently Asked Questions
5-Deoxyflavin (5-deazaflavin) is a flavin cofactor analog in which the N5 nitrogen atom of the isoalloxazine ring is replaced by a carbon atom (C5). This single-atom substitution fundamentally alters the redox chemistry: it abolishes the ability to form a neutral semiquinone radical intermediate, enforces obligatory two-electron hydride transfer rather than single-electron transfer (SET), raises the reduction potential, and converts the molecule into a weaker oxidant. These properties make it an indispensable mechanistic probe for distinguishing hydride transfer from SET pathways in flavoenzyme catalysis.
Semiquinone radical formation in native flavins relies on delocalization of the unpaired electron across the N5 position of the isoalloxazine ring. When N5 is replaced by carbon (C5), the electronic structure of the ring system changes dramatically — the carbon atom lacks the lone pair and electronegativity of nitrogen, disrupting the π-conjugation pathway essential for radical stabilization. Consequently, 5-deazaflavin cannot stabilize a one-electron-reduced semiquinone intermediate and proceeds exclusively via a concerted two-electron hydride transfer mechanism. This property is exploited experimentally to test whether a given flavoenzyme reaction proceeds through radical or hydride pathways.
5-Deazaflavin is used to probe the catalytic mechanism of flavin-dependent enzymes by acting as a selective hydride-transfer-only cofactor. Key applications include: (1) distinguishing between sequential one-electron (SET) and concerted two-electron (hydride) mechanisms, (2) trapping reaction intermediates that are too short-lived with native flavin, (3) studying substrate C-H bond cleavage where hydride abstraction is the rate-limiting step, (4) photochemical generation of the reduced 5-deazaflavin radical for time-resolved spectroscopy, and (5) designing mechanism-based enzyme inhibitors by exploiting altered redox potentials.
5-Deazaflavin should be stored at −20 °C in a tightly sealed, light-protected amber vial under an inert atmosphere (argon or nitrogen) to prevent photodegradation and oxidation. Allow the vial to equilibrate to room temperature before opening to avoid moisture condensation. Prepare stock solutions in anhydrous DMSO or DMF and aliquot into single-use portions to minimize freeze-thaw cycles. Protect from prolonged exposure to light during experimental use, as the compound exhibits sensitivity to UV-visible light. Under these conditions, the solid powder is stable for at least 2 years from the date of QC release.
UPOR Biotech supplies 5-Deoxyflavin (CAS 26908-38-3) as Research Grade (RUO) material with the following specifications: ≥98.0% purity by HPLC, identity confirmed by ¹H NMR and MS, appearance as a yellow to yellow-orange crystalline powder, melting point >300 °C, and UV-Vis λmax ~400-420 nm. Each shipment includes a comprehensive Certificate of Analysis (CoA) documenting lot-specific HPLC chromatogram, NMR spectrum, residual solvent analysis, heavy metals testing, and loss on drying. Manufacturing is performed under ISO 9001:2015 and c-GMP quality management systems. Safety Data Sheets (SDS), additional QC documentation, and bulk/research pricing are available upon request.