Universität zu Köln

Stoffels, Christopher, Oumari, Mhmd, Perrou, Aris, Termath, Andreas, Schlundt, Waldemar, Schmalz, Hans-Guenther, Schaefer, Mathias ORCID: 0000-0002-5943-4335, Wewer, Vera ORCID: 0000-0002-0199-5228, Metzger, Sabine, Schoemig, Edgar and Gruendemann, Dirk (2017). Ergothioneine stands out from hercynine in the reaction with singlet oxygen: Resistance to glutathione and TRIS in the generation of specific products indicates high reactivity. Free Radic. Biol. Med., 113. S. 385 - 395. NEW YORK: ELSEVIER SCIENCE INC. ISSN 1873-4596

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Abstract

The candidate vitamin ergothioneine (ET), an imidazole-2-thione derivative of histidine betaine, is generally considered an antioxidant. However, the precise physiological role of ET is still unresolved. Here, we investigated in vitro the hypothesis that ET serves specifically to eradicate noxious singlet oxygen (O-1(2)). Pure O-1(2) was generated by thermolysis at 37 degrees C of N, N'-di(2,3-dihydroxypropyl)-1,4-naphthalenedipropanamide 1,4-endoperoxide (DHPNO2). Assays of DHPNO2 with ET or hercynine (= ET minus sulfur) at pH 7.4 were analyzed by LC-MS in full scan mode to detect products. Based on accurate mass and product ion scan data, several products were identified and then quantitated as a function of time by selected reaction monitoring. All products of hercynine contained, after a [4 + 2] cycloaddition of O-1(2), a carbonyl at position 2 of the imidazole ring. By contrast, because of the doubly bonded sulfur, we infer from the products of ET as the initial intermediates a 4,5-dioxetane (after [2 + 2] cycloaddition) and hydroperoxides at position 4 and 5 (after Schenck ene reactions). The generation of single products from ET, but not from hercynine, was fully resistant to a large excess of tris (hydroxymethyl) aminomethane (TRIS) or glutathione (GSH). This suggests that O-1(2) markedly favors ET over GSH (at least 50-fold) and TRIS (at least 250-fold) for the initial reaction. Loss of ET was almost abolished in 5 mM GSH, but not in 25 mM TRIS. Regeneration of ET seems feasible, since some ET products - by contrast to hercynine products - decomposed easily in the MS collision cell to become aromatic again.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Stoffels, Christopher UNSPECIFIED UNSPECIFIED UNSPECIFIED Oumari, Mhmd UNSPECIFIED UNSPECIFIED UNSPECIFIED Perrou, Aris UNSPECIFIED UNSPECIFIED UNSPECIFIED Termath, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Schlundt, Waldemar UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmalz, Hans-Guenther UNSPECIFIED UNSPECIFIED UNSPECIFIED Schaefer, Mathias UNSPECIFIED orcid.org/0000-0002-5943-4335 UNSPECIFIED Wewer, Vera UNSPECIFIED orcid.org/0000-0002-0199-5228 UNSPECIFIED Metzger, Sabine UNSPECIFIED UNSPECIFIED UNSPECIFIED Schoemig, Edgar UNSPECIFIED UNSPECIFIED UNSPECIFIED Gruendemann, Dirk UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-209758
DOI:	10.1016/j.freeradbiomed.2017.10.372
Journal or Publication Title:	Free Radic. Biol. Med.
Volume:	113
Page Range:	S. 385 - 395
Date:	2017
Publisher:	ELSEVIER SCIENCE INC
Place of Publication:	NEW YORK
ISSN:	1873-4596
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Organic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MOLECULAR-OXYGEN; NAPHTHALENE ENDOPEROXIDE; HISTIDINE; TRANSPORTER; PHOTOOXIDATION; ANTIOXIDANT; DERIVATIVES; THIOLS; DAMAGE; DNA Multiple languages Biochemistry & Molecular Biology; Endocrinology & Metabolism Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/20975