Modification by Fluoride, Bromide, Iodide, Thiocyanate and Nitrite Anions of Reaction of a Myeloperoxidase-H2O2-Cl- System with Nucleosides.

Suzuki, Toshinori; Ohshima, Hiroshi

doi:10.1248/cpb.51.301

Cited by 8 publications

(8 citation statements)

References 39 publications

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“…Fluoride is the only halide that is known to be antimicrobial without oxidation (Hamilton, 1990;Van Loveren, 1990;Marquis, 1995;Jenkins, 1999). Fluoride influences the metabolism of cariogenic and other bacteria via multiple mechanisms (Marquis et al, 2003): Fcan bind directly to many enzymes (especially metalloenzymes) (Segal et al, 1968;Wever and Bakkenist, 1980;Zgliczynski et al, 1983;Thibodeau et al, 1985;Ferrari et al, 1997;Suzuki and Ohshima, 2003), thereby affecting their activities; catalase is inhibited by F -[thereby affecting the ability of H 2 O 2 to kill oral bacteria (Phan et al, 2001)]; and some Fcomplexes of metals (e.g., AlF 4 and BeF 3 -•H 2 O) can mimic phosphate, thereby affecting a variety of enzymes and regulatory phosphatases (Thongboonkerd et al, 2002). The weak-acid property of HF (pK a = 3.15), which is a transmembrane proton conductor, appears to be important for inducing the glycolytic inhibition of oral bacteria that is observed at low pH in dental plaque (Eisenberg and Marquis, 1981) (Table 4).…”

Section: Halidesmentioning

confidence: 99%

Inorganic Chemistry of Defensive Peroxidases in the Human Oral Cavity

Ashby

2008

J Dent Res

102

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The innate host response system is comprised of various mechanisms for orchestrating host response to microbial infection of the oral cavity. The heterogeneity of the oral cavity and the associated microenvironments that are produced give rise to different chemistries that affect the innate defense system. One focus of this review is on how these spatial differences influence the two major defensive peroxidases of the oral cavity, salivary peroxidase (SPO) and myeloperoxidase (MPO). With hydrogen peroxide (H2O2) as an oxidant, the defensive peroxidases use inorganic ions to produce antimicrobials that are generally more effective than H2O2 itself. The concentrations of the inorganic substrates are different in saliva vs. gingival crevicular fluid (GCF). Thus, in the supragingival regime, SPO and MPO work in unison for the exclusive production of hypothiocyanite (OSCN−, a reactive inorganic species), which constantly bathes nascent plaques. In contrast, MPO is introduced to the GCF during inflammatory response, and in that environment it is capable of producing hypochlorite (OCl−), a chemically more powerful oxidant that is implicated in host tissue damage. A second focus of this review is on inter-person variation that may contribute to different peroxidase function. Many of these differences are attributed to dietary or smoking practices that alter the concentrations of relevant inorganic species in the oral cavity ( e.g.: fluoride, F−; cyanide, CN−; cyanate, OCN−; thiocyanate, SCN−; and nitrate, NO3−). Because of the complexity of the host and microflora biology and the associated chemistry, it is difficult to establish the significance of the human peroxidase systems during the pathogenesis of oral diseases. The problem is particularly complex with respect to the gingival sulcus and periodontal pockets (where the very different defensive stratagems of GCF and saliva co-mingle). Despite this complexity, intriguing in vitro and in vivo studies are reviewed here that reveal the interplay between peroxidase function and associated inorganic chemistry.

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Section: Halidesmentioning

confidence: 99%

Inorganic Chemistry of Defensive Peroxidases in the Human Oral Cavity

Ashby

2008

J Dent Res

102

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“…Since HOCl can react with Br − to generate HOBr, a portion of HOCl formed by the MPO system would react with a plasma concentration Br − , converting it to HOBr. 7,8) HOBr can react with nucleic acid bases. HOBr reacted with thymidine, resulting in thymidine glycol and its phosphate derivative in phosphate buffer.…”

Section: ) Epo Uses the Plasma Concentration Of Brmentioning

confidence: 99%

Formation of 8-<i>S</i>-L-Cysteinyladenosine from 8-Bromoadenosine and Cysteine

Suzuki

Ogishi

Shinohara

et al. 2018

CHEMICAL & PHARMACEUTICAL BULLETIN

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When 8-bromoadenosine was incubated with cysteine at pH 7.2 and 37°C, an exclusive product was generated. This product was identified as a cysteine substitution derivative of adenosine at the 8 position, 8-S-Lcysteinyladenosine. The reaction accelerated as pH increased from mildly acidic to basic conditions. The isolated cysteine adduct of adenosine decreased with a half-life of 15 h at pH 7.2 and 37°C. Similar results were obtained for the incubation of 8-bromo-2′-deoxyadenosine and 8-bromoadenosine 3′,5′-cyclic monophosphate with cysteine. These results suggest that 8-bromoadenine in nucleotides, RNA, and DNA can react with thiols, resulting in adducts under physiological conditions. Key words 8-bromoadenosine; cysteine; cysteinyladenosine; 8-bromo-2′-deoxyadenosine; 8-bromo-cAMP HOBr can react with nucleic acid bases. HOBr reacted with thymidine, resulting in thymidine glycol and its phosphate derivative in phosphate buffer. 9) 2′-Deoxyguanosine (dGuo) and 2′-deoxycytidine (dCyd) are major targets in the reaction of HOBr. In in vitro studies, 8-bromo-2′-deoxyguanosine (8-BrdGuo) and 5-bromo-2′-deoxycytidine (5-Br-Cyd) were generated from dGuo and dCyd by reactions with reagent HOBr, an EPO/H 2 O 2 /Br − system, and other oxidant/Br − systems. 10-13)Recently, 8-Br-dGuo was detected in urine from healthy volunteers. 14) In diabetic patients, the urinary 8-Br-dGuo level was found to be 8-fold higher than that in healthy volunteers. This implies that nucleoside bromination occurs naturally in healthy humans and that inflammatory diseases greatly increase its level. For adenine (Ade) in nucleoside, the reactivity with HOBr is low. However, it has been reported that 8-bromoadenine (8-Br-Ade) is the major purine oxidation product generated in double-stranded DNA by either reagent HOBr or an EPO/H 2 O 2 /Br − system. 15)In our previous paper, we reported that the incubation of 8-bromoguanosine (8-Br-Guo) with L-cysteine (Cys) under physiological conditions (pH 7.4 and 37°C) generated 8-S-Lcysteinylguanosine (Cys-Guo) and guanosine (Guo). 16) In the present study, we investigated the reaction of 8-bromoadenosine (8-Br-Ado), 8-bromo-2′-deoxyadenosine (8-BrdAdo), and 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) with Cys, and report here the identification of the product and its comparison with the reaction of 8-Br-Guo with Cys. ResultsA solution of 100 µM 8-Br-Ado and 50 mM Cys was incubated in 100 mM potassium phosphate buffer at pH 7.2 and at a temperature of 37°C for 4 h. When the reaction mixture was analyzed by reversed phase (RP) HPLC, an unknown product peak showing a UV spectrum with λ max =279 nm was eluted at the retention time of 4.4 min in the chromatogram with a small peak of adenosine (Ado) (Fig. 1). Ado was confirmed by coincidence of the RP-HPLC retention time and UV and MS spectra of an authentic Ado. The unknown product was collected and subjected to spectrometric measurements. The product showed an electrospray ionization time of flight (ESI-TOF) MS spectrum with m/z=298 and 385 in the nega...

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“…15) Whereas the reactivity of 2′-deoxyadenosine (dA) with HOBr is low, 8-bromoadenine is the major purine oxidation product generated in double-stranded DNA by either reagent HOBr or HOBr generated by an EPO-H 2 O 2 -Br − system. 10) Recently, 8-Br-dG was reportedly detected in urine from healthy volunteers with a similar concentration of 8-chloro-2′-deoxyguanosine (8-Cl-dG), a product in the reaction of dG with HOCl, while both urinary 8-Br-dG and 8-Cl-dG levels from diabetic patients were 8-fold higher than the levels in healthy volunteers. 16) This implies that formation of HOBr as well as HOCl is important occurrence in inflammatory diseases in humans.…”

Section: Introductionmentioning

confidence: 99%

“…Since HOCl can react with Br − to generate HOBr, a portion of the HOCl formed by the MPO system will react with Br − at the plasma concentration, converting to HOBr. [8][9][10][11] HOBr can react with nucleic acid bases in nucleosides and DNA. 2′-Deoxyguanosine (dG) and 2′-deoxycytidine (dC) react with reagent HOBr and HOBr formed by EPO-H 2 O 2 -Br − systems, MPO-H 2 O 2 -Cl − -Br − systems, and other oxidant-Br − systems, generating several products including 8-bromo-2′-deoxyguanosine (8-Br-dG) and 5-bromo-2′deoxycytidine (5-Br-dC), respectively.…”

Section: Introductionmentioning

confidence: 99%

“…2′-Deoxyguanosine (dG) and 2′-deoxycytidine (dC) react with reagent HOBr and HOBr formed by EPO-H 2 O 2 -Br − systems, MPO-H 2 O 2 -Cl − -Br − systems, and other oxidant-Br − systems, generating several products including 8-bromo-2′-deoxyguanosine (8-Br-dG) and 5-bromo-2′deoxycytidine (5-Br-dC), respectively. [8][9][10][11][12][13][14] 2′-Deoxythymidine (dT) reacts with HOBr, resulting in thymidine glycol and its phosphate derivative in phosphate buffer. 15) Whereas the reactivity of 2′-deoxyadenosine (dA) with HOBr is low, 8-bromoadenine is the major purine oxidation product generated in double-stranded DNA by either reagent HOBr or HOBr generated by an EPO-H 2 O 2 -Br − system.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Urea on the Reactions of Nucleosides with Hypobromous Acid

Suzuki

Kumagai

Furusawa

2019

CHEMICAL & PHARMACEUTICAL BULLETIN

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Hypobromous acid (HOBr) is generated not only by eosinophils but also by neutrophils in the presence of Br at the plasma concentration. Reactivity of HOBr is greatly modulated by coexistent compounds such as amines and amides. In this study, we investigated effects of urea in the reaction of nucleosides with HOBr. When nucleosides were incubated with HOBr without urea in potassium phosphate buffer at pH 7.4 and 37°C, the reactions almost completed within 10 min, with consumptions in the order of 2′-deoxyguanosine > 2′-deoxycytidine > 2′-deoxythymidine > 2′-deoxyadenosine, generating 8-bromo-2′-deoxyguanosine and 5-bromo-2′-deoxycytidine. In the presence of urea, the reaction of nucleosides with HOBr was relatively slow, continuing over several hours. When HOBr was preincubated without urea in potassium phosphate buffer at pH 7.4 and 37°C for 48 h, the preincubated HOBr solution did not react with nucleosides. However, a similar preincubated solution of HOBr with urea reacted with nucleosides to generate 8-bromo-2′-deoxyguanosine and 5-bromo-2′-deoxycytidine. These results imply that a reactive bromine compound with a long life, probably bromourea, is generated by HOBr in neutral urea solution and reacts with nucleosides, resulting in brominated nucleosides.

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Modification by Fluoride, Bromide, Iodide, Thiocyanate and Nitrite Anions of Reaction of a Myeloperoxidase-H2O2-Cl- System with Nucleosides.

Cited by 8 publications

References 39 publications

Inorganic Chemistry of Defensive Peroxidases in the Human Oral Cavity

Inorganic Chemistry of Defensive Peroxidases in the Human Oral Cavity

Formation of 8-<i>S</i>-L-Cysteinyladenosine from 8-Bromoadenosine and Cysteine

Effects of Urea on the Reactions of Nucleosides with Hypobromous Acid

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