Universität zu Köln

Kaczmarek, Alexander T., Strampraad, Marc J. F., Hagedoorn, Peter-Leon ORCID: 0000-0001-6342-2022 and Schwarz, Guenter ORCID: 0000-0002-2118-9338 (2019). Reciprocal regulation of sulfite oxidation and nitrite reduction by mitochondrial sulfite oxidase. Nitric Oxide-Biol. Chem., 89. S. 22 - 32. SAN DIEGO: ACADEMIC PRESS INC ELSEVIER SCIENCE. ISSN 1089-8611

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Abstract

The oxygen-independent nitrate-nitrite-nitric oxide (NO) pathway is considered as a substantial source of NO in mammals. Dietary nitrate/nitrite are distributed throughout the body and reduced to NO by the action of various enzymes. The intermembrane spaced (IMS), molybdenum cofactor-dependent sulfite oxidase (SO) was shown to catalyze such a nitrite reduction. In this study we asked whether the primary function of SO - sulfite oxidation and its novel function - nitrite reduction - impact each other. First, we utilized benzyl viologen as artificial electron donor to investigate steady state NO synthesis by SO and found fast (k(cat) = 14 s(-1)) nitrite reduction of SO full-length and its isolated molybdenum domain at pH 6.5. Next, we determined the impact of nitrite on pre-steady state kinetics in SO catalysis and identified nitrite as a pH-dependent inhibitor of SO reductive and oxidative half reaction. Finally, we report on the time-dependent formation of the paramagnetic Mo(V) species following nitrite reduction and demonstrate that sulfite inhibits nitrite reduction. In conclusion, we propose a pH-dependent reciprocal regulation of sulfite oxidation and nitrite reduction by each substrate, thus facilitating quick responses to hypoxia induced changes in the IMS, which may function in protecting the cell from reactive oxygen species production.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kaczmarek, Alexander T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Strampraad, Marc J. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hagedoorn, Peter-Leon UNSPECIFIED orcid.org/0000-0001-6342-2022 UNSPECIFIED Schwarz, Guenter UNSPECIFIED orcid.org/0000-0002-2118-9338 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-134283
DOI:	10.1016/j.niox.2019.04.004
Journal or Publication Title:	Nitric Oxide-Biol. Chem.
Volume:	89
Page Range:	S. 22 - 32
Date:	2019
Publisher:	ACADEMIC PRESS INC ELSEVIER SCIENCE
Place of Publication:	SAN DIEGO
ISSN:	1089-8611
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Biochemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DIETARY NITRATE; BLOOD-PRESSURE; INORGANIC NITRATE; HYDROGEN-SULFIDE; ENDOTHELIAL FUNCTION; MOLYBDENUM COFACTOR; SALIVARY-GLANDS; COMPONENT; PROTEIN; HUMANS Multiple languages Biochemistry & Molecular Biology; Cell Biology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13428