Dihydrolipoic acid reduces cytochrome b561 proteins

Bérczi, Alajos; Zimányi, László; Asard, Han

doi:10.1007/s00249-012-0812-x

Cited by 7 publications

(13 citation statements)

References 53 publications

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“…Spectrum analysis of mouse and bovine CGCytb/CYB561A1 and of TSCytb/CYB561D2 revealed the presence of two distinct, split a-bands in the spectrum of ASC-reduced proteins, which is consistent with the presence of two heme pockets (9,12,28). In Arabidopsis TCytb/CYB561B1 and mouse TSCytb/CYB561D2, singular value decomposition analysis identified two distinct b-type heme spectra that could be assigned to the two CYB561 hemes (12,16).…”

Section: Asc Reducibilitymentioning

confidence: 70%

“…Reduction by NAD(P)H of various CYB561 isoforms never exceeded 5% (relative to DTH) (12,57). GSH does not reduce CYB561, but other thiol reagents, in particular dihydrolipoic acid (DHLA), are almost as efficient as ASC in reducing mouse CGCytb/CYB561A1 and TSCytb/CYB561D2; however, with only one apparent, high affinity, binding site (12).…”

Section: Other Reducing Agentsmentioning

confidence: 98%

“…In Arabidopsis TCytb/CYB561B1 and mouse TSCytb/CYB561D2, singular value decomposition analysis identified two distinct b-type heme spectra that could be assigned to the two CYB561 hemes (12,16). The property of split a-bands points to the fact that each heme is located in an anisotropic electrostatic field, originating from the distribution of charged amino acid residues around the heme pockets.…”

Section: Asc Reducibilitymentioning

confidence: 99%

“…GSH does not reduce CYB561, but other thiol reagents, in particular dihydrolipoic acid (DHLA), are almost as efficient as ASC in reducing mouse CGCytb/CYB561A1 and TSCytb/CYB561D2; however, with only one apparent, high affinity, binding site (12). In addition, the Arabidopsis TCytb/CYB561B1 was reduced by DHLA, although with much lower sensitivity and biphasic concentration dependence (12). Thus, it is possible that DHLA plays a different role in CYB561 reduction in plants and animals.…”

Section: Other Reducing Agentsmentioning

confidence: 99%

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Cytochromesb561: Ascorbate-Mediated Trans-Membrane Electron Transport

Asard

Barbaro

Trost

et al. 2013

Antioxidants & Redox Signaling

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Significance: Cytochromes b561 (CYB561s) constitute a family of trans-membrane (TM), di-heme proteins, occurring in a variety of organs and cell types, in plants and animals, and using ascorbate (ASC) as an electron donor. CYB561s function as monodehydroascorbate reductase, regenerating ASC, and as Fe 3+ -reductases, providing reduced iron for TM transport. A CYB561-core domain is also associated with dopamine bmonooxygenase redox domains (DOMON) in ubiquitous CYBDOM proteins. In plants, CYBDOMs form large protein families. Physiological functions supported by CYB561s and CYBDOMs include stress defense, cell wall modifications, iron metabolism, tumor suppression, and various neurological processes, including memory retention. CYB561s, therefore, significantly broaden our view on the physiological roles of ASC. Recent Advances: The ubiquitous nature of CYB561s is only recently being recognized. Significant advances have been made through the study of recombinant CYB561s, revealing structural and functional properties of a unique ''two-heme four-helix'' protein configuration. In addition, the DOMON domains of CYBDOMs are suggested to contain another heme b. Critical Issues: New CYB561 proteins are still being identified, and there is a need to provide an insight and overview on the various roles of these proteins and their structural properties. Future Directions: Mutant studies will reveal in greater detail the mechanisms by which CYB561s and CYBDOMs participate in cell metabolism in plants and animals. Moreover, the availability of efficient heterologous expression systems should allow protein crystallization, more detailed (atomic-level) structural information, and insights into the intramolecular mechanism of electron transport.

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Section: Asc Reducibilitymentioning

confidence: 70%

Section: Other Reducing Agentsmentioning

confidence: 98%

Section: Asc Reducibilitymentioning

confidence: 99%

Section: Other Reducing Agentsmentioning

confidence: 99%

See 2 more Smart Citations

Cytochromesb561: Ascorbate-Mediated Trans-Membrane Electron Transport

Asard

Barbaro

Trost

et al. 2013

Antioxidants & Redox Signaling

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“…While the bulk of evidence suggests that ascorbate is the major electron donor for many of the cytochromes b 561 [ 39 ], a recent report suggests that dihydrolipoic acid can donate electrons to some cytochromes b 561 under certain conditions [ 74 ]. However, there is no direct evidence that dihydrolipoic acid can donate electrons to DCYTB.…”

Section: Dcytb and Ascorbate: A Critical Link In Iron Metabolism?mentioning

confidence: 99%

Duodenal Cytochrome b (DCYTB) in Iron Metabolism: An Update on Function and Regulation

et al. 2015

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Iron and ascorbate are vital cellular constituents in mammalian systems. The bulk-requirement for iron is during erythropoiesis leading to the generation of hemoglobin-containing erythrocytes. Additionally, both iron and ascorbate are required as co-factors in numerous metabolic reactions. Iron homeostasis is controlled at the level of uptake, rather than excretion. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance non-heme iron absorption in the gut, ascorbate regulates iron homeostasis. The involvement of ascorbate in dietary iron absorption extends beyond the direct chemical reduction of non-heme iron by dietary ascorbate. Among other activities, intra-enterocyte ascorbate appears to be involved in the provision of electrons to a family of trans-membrane redox enzymes, namely those of the cytochrome b561 class. These hemoproteins oxidize a pool of ascorbate on one side of the membrane in order to reduce an electron acceptor (e.g., non-heme iron) on the opposite side of the membrane. One member of this family, duodenal cytochrome b (DCYTB), may play an important role in ascorbate-dependent reduction of non-heme iron in the gut prior to uptake by ferrous-iron transporters. This review discusses the emerging relationship between cellular iron homeostasis, the emergent “IRP1-HIF2α axis”, DCYTB and ascorbate in relation to iron metabolism.

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