Singlet Oxygen‐Mediated Inactivation of Acetylcholinesterase: A Comparison of Purified Enzyme in Solution and Enzyme Bound to K562 Leukemia Cells

Deadwyler, Gail; Sima, Paul D.; Fu, Yingxian; Kanofsky, Jeffrey R.

doi:10.1111/j.1751-1097.1997.tb01939.x

Cited by 16 publications

(9 citation statements)

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“…1 O 2 not only inactivates CuZnSOD, MnSOD, and catalase in vitro and in vivo, but also can inactivate other enzyme activities. For example, 1 O 2 can inactivate acetylcholinesterase, bacterial respiratory chain enzymes, blood coagulation factor I (fibrinogen), factor V, factor VIII, and factor X (9,34,36). We can infer from these results that a complicated relation exists between cellular antioxidants and cellular ROS.…”

Section: Singlet Oxygen Inactivates Antioxidant Enzymes 1311mentioning

confidence: 89%

Inactivation of Primary Antioxidant Enzymes in Mouse Keratinocytes by Photodynamically Generated Singlet Oxygen

Luo

Zhang

et al. 2006

Antioxidants & Redox Signaling

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Cellular antioxidant enzymes protect against damage caused by exposure to endogenous or exogenous prooxidants. Singlet oxygen ((1)O(2)) is a reactive form of oxygen that can be produced in vivo either in normal and pathophysiologic conditions or by photosensitizing chemicals, as during photodynamic treatment. We hypothesized that photodynamically generated (1)O(2) would decrease the enzymatic activities of cellular antioxidants. To test this hypothesis, we treated cultured mouse epidermal keratinocytes with the photosensitizer Photofrin plus visible light to produce (1)O(2), and then measured CuZnSOD, MnSOD, and catalase activities with both ingel and spectrophotometric enzyme activity assays. Our results demonstrated that the enzymatic activities of cellular CuZnSOD, MnSOD, and catalase were significantly decreased after keratinocytes were treated with Photofrin plus visible light. By contrast, the enzymatic activities of cellular CuZnSOD, MnSOD, and catalase were unaffected in control cells treated with Photofrin only or visible light only. Despite the decreased levels of enzymatic activities, the protein levels of all three primary antioxidant enzymes remained constant after photodynamic treatment, as determined by Western blotting. L-Histidine, a (1)O(2) quencher, protected against the inactivation of cellular CuZnSOD, MnSOD, and catalase enzymes induced by photodynamically generated (1)O(2). The conclusion from these experiments is that the primary cellular antioxidant enzymes CuZnSOD, MnSOD, and catalase can be inactivated by photodynamically generated (1)O(2) in nucleated mammalian cells. These findings may be useful in the future development of antineoplastic adjuvant therapies that use photodynamic generation of (1)O(2) to inactivate antioxidant defenses with a goal of sensitizing tumor cells to prooxidant-generating drugs.

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Section: Singlet Oxygen Inactivates Antioxidant Enzymes 1311mentioning

confidence: 89%

Inactivation of Primary Antioxidant Enzymes in Mouse Keratinocytes by Photodynamically Generated Singlet Oxygen

Luo

Zhang

et al. 2006

Antioxidants & Redox Signaling

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“…First, the lifetime of singlet oxygen within the various membrane structures within the cell may be much shorter than the average lifetime within the cell, of the order of 0.03 s (2,44). Second, singlet oxygen can avoid quenching by diffusing away from the organelles (4,5,45,46).…”

Section: Discussionmentioning

confidence: 99%

“…Singlet oxygen is a highly reactive cellular toxin with a lifetime of the order of 0.3 s within the cell (1)(2)(3)(4). It is gen- ¶Posted on the website on 2 February 2001.…”

Section: Introductionmentioning

confidence: 99%

Girard's Reagent P Derivative of β-Apo-8′-carotenal: A Potent Photoprotective Agent†¶

Kanofsky

Sima

2007

Photochemistry and Photobiology

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A cationic carotenoid derivative (GRP‐carotenal) was synthesized by the reaction of Girard's reagent P and β‐apo‐8′‐carotenal. The singlet‐oxygen quenching constants for GRP‐carotenal were 1.3 ± 0.1 × 1010 and 1.0 ± 0.1 × 1010M−1 s−1 in acetonitrile and in detergent micelles, respectively. Photosensitized damage to K562 leukemia cells from cis‐di(4‐sulfonatophenyl)diphenylporphine, hypericin and protoporphyrin IX was inhibited by GRP‐carotenal under conditions where β‐apo‐8′‐carotenal, β‐carotene and crocetin were ineffective. The unique cytoprotective properties of GRP‐carotenal, relative to the other carotenoids studied, could not be explained by the differences in the cell content of the various carotenoids or by the changes in the cell content of the photosensitizers used. Photosensitizer fluorescence from labeled K562 cells was reduced by GRP‐carotenal but not by the other carotenoids studied. The novel photoprotective properties of GRP‐carotenal may be due to its subcellular distribution. In photosensitizer‐containing detergent micelles, novel properties of GRP‐carotenal were not apparent. None of the carotenoids studied reduced photosensitizer fluorescence or singlet‐oxygen generation. Singlet‐oxygen quenching by GRP‐carotenal and by β‐apo‐8′‐carotenal were roughly the same. Crocetin has a singlet‐oxygen quenching constant that is about a factor of five lower. Singlet‐oxygen quenching by β‐carotene was limited by its aggregation.

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“…Specificity may signify a physiological role for singlet oxygen in calcium oscillations or other physiological functions. A short lifetime in cellular milieu (1 μ S) and a restricted effective reactive distance (<20 nm) may indeed be some of the qualifying characteristics for singlet oxygen to be an endogenous mediator (Deadwyler et al ., 1997; Cui & Matthews, 1998).…”

Section: Discussionmentioning

confidence: 99%

Selective activation by photodynamic action of cholecystokinin receptor in the freshly isolated rat pancreatic acini

Xiao

Cui

et al. 2003

British J Pharmacology

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1 Sulphonated aluminium phthalocyanine (SALPC) photodynamic action induces amylase secretion and permanent calcium oscillation in rat pancreatic acinar cells, because of the activation of phospholipase C or signalling proteins upstream. The aim of the present study was to investigate the involvement of muscarinic acetylcholine and cholecystokinin (CCK) receptors. 3 Amylase secretion induced by SALPC photodynamic action was not inhibited when atropine and FK480 were present during photodynamic action. However, addition of FK480 1 mm after initiation of photodynamic action inhibited photodynamic amylase secretion. Bethanechol (10, 100 mm) added after photodynamic action resulted in a full secretory response. 4 Atropine (10 nm) abolished calcium oscillation induced by bethanechol (5 mm), and FK480 (10 nm) blocked calcium oscillation induced by CCK (10 pm). 5 Atropine up to 10 mm was without effect on Ca 2 þ oscillation triggered by photodynamic action, but these oscillations were abolished by FK480 (10 nm). FK480 (10 nm) had no effect on calcium oscillations induced by bethanechol (5 mm). Bethanechol 5 mm, added after FK480 blockade of photodynamic calcium oscillation, still triggered regular calcium oscillation. 6 It is concluded that SALPC photodynamic action selectively and permanently activates CCK receptor in rat pancreatic acini. Such permanent and selective modulation of signalling proteins has important implications for the treatment of pancreatitis, prion diseases, and neurodegenerative disorders.

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Singlet Oxygen‐Mediated Inactivation of Acetylcholinesterase: A Comparison of Purified Enzyme in Solution and Enzyme Bound to K562 Leukemia Cells

Cited by 16 publications

References 50 publications

Inactivation of Primary Antioxidant Enzymes in Mouse Keratinocytes by Photodynamically Generated Singlet Oxygen

Inactivation of Primary Antioxidant Enzymes in Mouse Keratinocytes by Photodynamically Generated Singlet Oxygen

Girard's Reagent P Derivative of β-Apo-8′-carotenal: A Potent Photoprotective Agent†¶

Selective activation by photodynamic action of cholecystokinin receptor in the freshly isolated rat pancreatic acini

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