S-(2,4-dinitrophenyl)glutathione

Summary

S-(2,4-dinitrophenyl)glutathione (DNP‑SG) is a synthetic glutathione‑S‑conjugate used primarily as a model substrate in biochemical research. It enables the study of ATP‑dependent transport systems that move glutathione conjugates across cellular membranes, such as the canalicular bile‑acid transporter in rat liver, plant vacuolar transporters, and the RLIP76 protein in mammalian cells.

Mechanism of Action

DNP‑SG is recognized by ATP‑driven transport proteins that bind the conjugate and use the energy from ATP hydrolysis to translocate it across the membrane. In rat liver canalicular vesicles the uptake is directly ATP‑dependent, showing a Km of ~71 µM, and is not driven by a membrane potential. Thiol groups near the transporter’s active site are essential, as thiol‑reactive reagents inhibit transport. Similar ATP‑dependent mechanisms operate in plant vacuolar membranes and in RLIP76‑mediated efflux in erythrocytes and cultured cells.

What the Research Shows

Early work with rat liver canalicular membrane vesicles demonstrated that DNP‑SG is accumulated up to 5.5‑fold in an ATP‑dependent manner, with competitive inhibition by related thioethers and bile acids, indicating a shared transport pathway. Plant studies showed that pretreatment with the precursor CDNB up‑regulates an MgATP‑driven vacuolar DNP‑SG transporter, increasing Vmax without altering Km. Human erythrocyte membrane vesicles display an ATPase that is activated by DNP‑SG, as well as by classic uncouplers, suggesting the transporter can be stimulated by small anionic lipophiles. RLIP76, a non‑ABC GTPase‑activating protein, catalyzes ATP‑dependent export of DNP‑SG and other glutathione conjugates, contributing to cellular resistance to oxidative stress. Thiol‑disulfide exchange modulates transporter activity, with reagents like DTNB and N‑ethylmaleimide inactivating transport in a reversible, dose‑dependent fashion.

Reported Benefits

Because DNP‑SG is a well‑characterized, readily synthesized substrate, it provides a quantitative probe for measuring kinetic parameters (Km, Vmax) of glutathione‑conjugate transporters. It has been used to identify and compare transporter specificity, to assess the impact of regulatory agents (e.g., CDNB, uncouplers), and to explore the role of thiol groups in transporter function across species. Its use has clarified the ATP‑driven nature of several transport systems and facilitated the discovery of proteins such as RLIP76.

Limitations of the Evidence

All reported data derive from isolated membrane vesicle preparations, plant tissue extracts, or reconstituted proteoliposomes; in vivo relevance of DNP‑SG transport remains untested. The compound is a synthetic analogue rather than a physiological substrate, so findings may not fully extrapolate to endogenous glutathione conjugates. No clinical or therapeutic applications have been demonstrated, and the literature does not address long‑term cellular effects of DNP‑SG exposure.

Safety Considerations

DNP‑SG contains a dinitrophenyl moiety, a structural feature associated with mitochondrial uncoupling in related compounds, raising potential toxicity concerns. The abstracts report only in vitro use; no human safety data exist. Standard laboratory chemical safety practices (gloves, eye protection, fume hood) are advised. Researchers should handle the compound as a potentially hazardous chemical and dispose of waste according to institutional regulations.

How It Is Administered

The compound is employed exclusively in experimental settings, typically added to isolated membrane vesicle suspensions, plant tissue extracts, or proteoliposome assays. It is not formulated for oral, injectable, or other therapeutic routes, and no dosage regimens are described in the literature.

Routes of Administration

No administration routes recorded yet.

Goals & Uses

• Multidrug resistance investigationResearch / OncologyModerate
• GST activity measurementResearch / Biochemical AssayHigh
• Cellular detoxification pathway studiesResearch / ToxicologyModerate
• MRP1/MRP2 transport characterizationResearch / Transporter BiologyHigh

Contraindications

• Human therapeutic useRegulatory/safetyHigh

Adverse Effects

• Cytotoxicity (in vitro)ToxicityCommon

Drug Interactions

• MRP1/ABCC1 inhibitors (e.g., MK-571)Low

Population Constraints

• All human populationsGeneralAbsolute

Regulatory Status

• European UnionUnapprovedNo EMA regulatory status; used solely as a laboratory biochemical.
• United StatesUnapprovedResearch reagent only; not reviewed or approved by the FDA for any therapeutic indication.
• United KingdomUnapprovedNo MHRA regulatory status; research use only.

No regulatory approval in any jurisdiction. Used exclusively as a biochemical research reagent. Not intended for human or veterinary therapeutic use.

Evidence & Sources

• [Preparation of plasma membrane and the analysis of transport kinetics and driving forces]
  Journal ArticleModerateNiinuma K, et al.1996-01-01T00:00:00.000000Z
• 1-Chloro-2,4-Dinitrobenzene-Elicited Increase in Vacuolar Glutathione-S-Conjugate Transport Activity
  Journal ArticleLowLi ZS, Zhen RG, Rea PA1995-01-01T00:00:00.000000Z
• ATP-dependent S-(2,4-dinitrophenyl)glutathione transport in canalicular plasma membrane vesicles from rat liver
  Journal ArticleLowAkerboom TP, et al.1991-01-01T00:00:00.000000Z
• 2,4-Dinitrophenol and carbonylcyanide p-trifluoromethoxyphenylhydrazone activate the glutathione S-conjugate transport ATPase of human erythrocyte membranes
  Journal ArticleLowWinter CG, DeLuca DC, Szumilo H1994-01-01T00:00:00.000000Z
• Transport functions and physiological significance of 76 kDa Ral-binding GTPase activating protein (RLIP76)
  Journal ArticleModerateAwasthi S, et al.2002-01-01T00:00:00.000000Z
• The role of thiols in ATP-dependent transport of S-(2,4-dinitrophenyl)glutathione by rat liver plasma membrane vesicles
  Journal ArticleLowMatsuda Y, et al.1996-01-01T00:00:00.000000Z

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