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The interaction of hemin, a porphyrin derivative, with the purified rat brain 2-oxoglutarate carrier

TitleThe interaction of hemin, a porphyrin derivative, with the purified rat brain 2-oxoglutarate carrier
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2021
AuthorsMiniero, D.V., Spagnoletta Anna, Gambacorta N., Scalera V., Pierri C.L., Nicolotti O., and De Palma A.
Date PublishedJan-08-2021
Keywords2 oxoglutaric acid, acrylamide, Apoptosis, article, azolectin, binding site, Brain, brain mitochondrion, buffer, cardiolipin, Centrifugation, cytoplasm, detergent, Dimethyl sulfoxide, disorders of mitochondrial functions, dodecyl sulfate sodium, edetic acid, Enzyme kinetics, heme, hemin, hydrogen bond, Hydroxyapatite, incubation time, infusorial earth, ion exchange resin, liposome, malic acid, metabolism, molecular docking, Molecular Weight, N, n' methylenebisacrylamide, Nitrogen, nonhuman, oxidative phosphorylation, phospholipid, polyacrylamide gel electrophoresis, porphyrin, proteoliposome, protonation, pyridoxal 5 phosphate, radioactivity, rat, sephadex, silver nitrate, Sodium chloride, sodium sulfate, tautomerization, transport assay, triton x 100, triton x 114

The mitochondrial 2-oxoglutarate carrier (OGC), isolated and purified from rat brain mito-chondria, was reconstituted into proteoliposomes to study the interaction with hemin, a porphyrin derivative, which may result from the breakdown of heme-containing proteins and plays a key role in several metabolic pathways. By kinetic approaches, on the basis of the single binding centre gated pore mechanism, we analyzed the effect of hemin on the transport rate of OGC in uptake and efflux experiments in proteoliposomes reconstituted in the presence of the substrate 2-oxoglutarate. Overall, our experimental data fit the hypothesis that hemin operates a competitive inhibition in the 0.5–10 µM concentration range. As a consequence of the OGC inhibition, the malate/aspartate shuttle might be impaired, causing an alteration of mitochondrial function. Hence, considering that the metabolism of porphyrins implies both cytoplasmic and mitochondrial processes, OGC may participate in the regulation of porphyrin derivatives availability and the related metabolic pathways that depend on them (such as oxidative phosphorylation and apoptosis). For the sake of clarity, a simplified model based on induced-fit molecular docking supported the in vitro transport assays findings that hemin was as good as 2-oxoglutarate to bind the carrier by engaging specific ionic hydrogen bond interactions with a number of key residues known for participating in the similarly located mitochondrial carrier substrate binding site. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.


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Short TitleBiomolecules
Citation KeyMiniero2021