Journal article
Sulfite Oxidase Catalyzes Single-Electron Transfer at Molybdenum Domain to Reduce Nitrite to Nitric Oxide
Antioxidants & redox signaling, Vol.23(4), pp.283-294
08/01/2015
DOI: 10.1089/ars.2013.5397
PMCID: PMC4523048
PMID: 25314640
Abstract
Aims:
Recent studies suggest that the molybdenum enzymes xanthine oxidase, aldehyde oxidase, and mARC exhibit nitrite reductase activity at low oxygen pressures. However, inhibition studies of xanthine oxidase in humans have failed to block nitrite-dependent changes in blood flow, leading to continued exploration for other candidate nitrite reductases. Another physiologically important molybdenum enzyme—sulfite oxidase (SO)—has not been extensively studied.
Results:
Using gas-phase nitric oxide (NO) detection and physiological concentrations of nitrite, SO functions as nitrite reductase in the presence of a one-electron donor, exhibiting redox coupling of substrate oxidation and nitrite reduction to form NO. With sulfite, the physiological substrate, SO only facilitates one turnover of nitrite reduction. Studies with recombinant heme and molybdenum domains of SO indicate that nitrite reduction occurs at the molybdenum center via coupled oxidation of Mo(IV) to Mo(V). Reaction rates of nitrite to NO decreased in the presence of a functional heme domain, mediated by steric and redox effects of this domain. Using knockdown of all molybdopterin enzymes and SO in fibroblasts isolated from patients with genetic deficiencies of molybdenum cofactor and SO, respectively, SO was found to significantly contribute to hypoxic nitrite signaling as demonstrated by activation of the canonical NO-sGC-cGMP pathway.
Innovation:
Nitrite binds to and is reduced at the molybdenum site of mammalian SO, which may be allosterically regulated by heme and molybdenum domain interactions, and contributes to the mammalian nitrate-nitrite-NO signaling pathway in human fibroblasts.
Conclusion:
SO is a putative mammalian nitrite reductase, catalyzing nitrite reduction at the Mo(IV) center.
Antioxid. Redox Signal.
23, 283–294.
Details
- Title: Subtitle
- Sulfite Oxidase Catalyzes Single-Electron Transfer at Molybdenum Domain to Reduce Nitrite to Nitric Oxide
- Creators
- Jun Wang - University of PittsburghSabina Krizowski - University of CologneKatrin Fischer-Schrader - University of CologneDimitri Niks - University of California, RiversideJesús Tejero - University of PittsburghCourtney Sparacino-Watkins - University of PittsburghLing Wang - University of PittsburghVenkata Ragireddy - University of PittsburghSheila Frizzell - University of PittsburghEric E. Kelley - University of PittsburghYingze Zhang - University of PittsburghPartha Basu - Duquesne UniversityRuss Hille - University of California, RiversideGuenter Schwarz - University of CologneMark T. Gladwin - University of Pittsburgh
- Resource Type
- Journal article
- Publication Details
- Antioxidants & redox signaling, Vol.23(4), pp.283-294
- DOI
- 10.1089/ars.2013.5397
- PMID
- 25314640
- PMCID
- PMC4523048
- NLM abbreviation
- Antioxid Redox Signal
- ISSN
- 1523-0864
- eISSN
- 1557-7716
- Publisher
- Mary Ann Liebert, Inc
- Language
- English
- Date published
- 08/01/2015
- Academic Unit
- Orthopedics and Rehabilitation
- Record Identifier
- 9984304719402771
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