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Strong modulation of nitrite reductase activity of cytoglobin by disulfide bond oxidation: Implications for nitric oxide homeostasis

Reeder, BJ and Ukeri, J (2017) 'Strong modulation of nitrite reductase activity of cytoglobin by disulfide bond oxidation: Implications for nitric oxide homeostasis.' Nitric Oxide: Biology and Chemistry. ISSN 1089-8603

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Abstract

Globin-mediated nitric oxide (NO) dioxygenase and nitrite reductase activities have been proposed to serve protective functions within the cell by scavenging or generating NO respectively. Cytoglobin has rapid NO dioxygenase activity, similar to other globins, however, the apparent rates of nitrite reductase activity have been reported as slow or negligible. Here we report that the activity of cytoglobin nitrite reductase activity is strongly dependent on the oxidation state of the two surface-exposed cysteine residues. The formation of an intramolecular disulfide bond between cysteines C38 and C83 enhances the nitrite reductase activity by 50-fold over that of the monomer with free sulfhydryl or 140-fold over that of the dimer with intermolecular disulfide bonds. The NO dioxygenase reactivity of cytoglobin is very rapid with or without disulfide bond, however, binding of the distal histidine following dissociation of the nitrate are affected by the presence or absence of the disulfide bond. The nitrite reductase activity reported here for the monomer with intramolecular disulfide is much higher than of those previously reported for other mammalian globins, suggesting a plausible role for this biochemistry in controlling NO homeostasis the cell under oxidative and ischemic conditions.

Item Type: Article
Uncontrolled Keywords: Cytoglobin, Nitrite, Reductase, Nitric oxide, Dioxygenase, Disulfide
Subjects: Q Science > QD Chemistry
Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science and Health > Biological Sciences, School of
Depositing User: Elements
Date Deposited: 21 Nov 2017 15:28
Last Modified: 08 Nov 2018 02:00
URI: http://repository.essex.ac.uk/id/eprint/20693

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