Effect of pH on mutagenesis by thiols in Salmonella typhimurium TA102

Stark, Avishay‐Abraham; Arad, Aya; Siskindovich, Sandra; Pagano, Dennis A.; Zeiger, Errol

doi:10.1016/0165-1218(89)90007-4

Cited by 42 publications

(11 citation statements)

References 9 publications

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“…The mutagenicity results in Salmonella presented, although weak, are consistent with this hypothesis in view of the unique sensitivity of TA 102 to oxygen radicals. The utilization of this strain was originally suggested because it was reported to be sensitive to peroxides and substances that form oxygen radicals [Levin et al, 19821, peroxides and radical generators [Stark et al, 1989;Abu-Shakra and Zeiger, 19901. Ozone produces chemical alterations in DNA bases [Sawadaishi et al, 19851 and it is possible that, apart from base degradation, oxidation of bases occurs to yield moeities such as thymine glycol and 5-hydroxymethyluracil [Steinberg et al, 19901.…”

Section: Resultsmentioning

confidence: 99%

Ozone is mutagenic in salmonella

Dillon¹,

Combes²,

McConville³

et al. 1992

Environ and Mol Mutagen

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Ozone is a highly reactive gas that has been tested for genotoxicity in a number of systems. Induced genetic damage resulting from ozone treatment may not be readily observed because of the high toxicity of the chemical and difficulties in generating and administering controlled concentrations. The mutagenicity of ozone was investigated in Salmonella typhimurium using a plate test protocol designed for reactive vapours and gases. Ozone, at two to three consecutive doses, induced weak, albeit statistically significant, mutagenic responses in tester strain TA102 with and without Aroclor-induced rat liver s9 (lowest effective mean concentration of 0.019 ppm; 35 min total exposure). However, dose-related responses were not always obtained. No mutagenicity was detected in strains TA98, TA100, or TA1535, with or without S9. In strain TA104, ozone induced a weak response only at a single dose with S9; this response was not reproducible. Mutagenicity was dependent on the ozone flow rate and total exposure time, with variations in the optimum dase-time regimen leading to toxicity or complete inactivity. The data show that ozone is a very weak bacterial mutagen and only when tested under narrowly prescribed, subtoxic dosing conditions. 0 1992 Wiley-Liss, Inc.

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Section: Resultsmentioning

confidence: 99%

Ozone is mutagenic in salmonella

Dillon¹,

Combes²,

McConville³

et al. 1992

Environ and Mol Mutagen

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“…This effect was observed over a broad range of GGT activities and GSH concentrations [27]. Previous studies had shown that the pKa of the cysteinyl-glycine thiol is significantly lower than that of GSH [4,28]. The ability of GGT to enhance iron reduction by GSH might therefore reflect the formation of cysteinyl-glycine, bearing a thiol moiety which dissociates more rapidly at near-neutral pH, and can thus redox-couple with Fe(III).…”

Section: Transferrinmentioning

confidence: 96%

γ‐Glutamyltransferase‐dependent prooxidant reactions: A factor in multiple processes

et al. 2003

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“…Given the pKa for cysteine, cysteinylglycine, glutathione, and homocysteine are 8. 15, 6.36, 8.58, and 8.87, 24 respectively, the fractional dissociation of the respective thiols will be 0.066, 0.814, 0.026, and 0.013 at the pH used in this study. Despite an approximately fivefold decreased concentration of cysteinylglycine, a ϳ12.3-fold increased ionization is likely to result cysteinylglycine to be the primary thiol cleaving the disulfide linkages in extracellular medium.…”

Section: ϫPhmentioning

confidence: 99%

Imparting mineral affinity to proteins with thiol–labile disulfide linkages

Bansal

Wright

Zhang

et al. 2005

J Biomedical Materials Res

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Chemical conjugation of bisphosphonates (BPs) to proteins is an effective means to enhance binding of proteins to mineral-containing biomaterials. BPs linked to proteins with reversible (i.e., cleavable) linkages were considered desirable over the conjugates linked with stable linkages because cleavable linkages allow protein release in free form from the mineral-containing biomaterials. To explore the feasibility of creating cleavable BP-protein conjugates, an amine- and a thiol-containing BP were conjugated to the model protein Bovine Serum Albumin (BSA) with N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP), which resulted in disulfide-linked BP-BSA conjugates. Although disulfide-linked conjugates were stable under aqueous conditions, the conjugates in solution were readily cleaved in the presence of physiological concentrations (approximately 0.3 mM) of the thiol compound, cysteine. The imparted mineral affinity as a result of BP conjugation, as assessed by hydroxyapatite (HA) binding in vitro, was lost upon cleavage of the disulfide-linked BP. The conjugates bound to HA were also cleavable with cysteine, but their cleavage rate was significantly reduced as compared to the conjugates in solution. In conclusion, disulfide-linked BP conjugates were shown to be readily cleavable by the amino acid cysteine and this resulted in the loss of imparted mineral affinity of the proteins. The proposed approach will be useful for modulating in vivo delivery of proteins implanted with mineral-containing biomaterials.

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Effect of pH on mutagenesis by thiols in Salmonella typhimurium TA102

Cited by 42 publications

References 9 publications

Ozone is mutagenic in salmonella

Ozone is mutagenic in salmonella

γ‐Glutamyltransferase‐dependent prooxidant reactions: A factor in multiple processes

Imparting mineral affinity to proteins with thiol–labile disulfide linkages

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