Determination of Singlet Oxygen and Electron Transfer Mediated Mechanisms of Photosensitized Protein Damage by Phosphorus(V)porphyrins

Hirakawa, Kazuhiko; Umemoto, Hironobu; Kikuchi, Ryô; Yamaguchi, Hiroki; Nishimura, Yukio; Okazaki, Satoshi; Segawa, Hiroshi

doi:10.1021/tx500492w

Cited by 39 publications

(63 citation statements)

References 35 publications

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“…Oxidation of tryptophan residue in a certain protein can be examined with a fluorometer [115]. For example, human serum albumin (HSA) has one tryptophan residue, and the intrinsic fluorescence of tryptophan at around 350 nm can be diminished by the oxidative damage.…”

Section: Protein Oxidation By 1 Omentioning

confidence: 99%

Biomolecules Oxidation by Hydrogen Peroxide and Singlet Oxygen

Hirakawa¹

2018

Reactive Oxygen Species (ROS) in Living Cells

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Hydrogen peroxide (H 2 O 2) and singlet oxygen (1 O 2) are important reactive oxygen species (ROS) for biological and medicinal fields. Oxidation processes of chemical materials by molecular oxygen are important H 2 O 2 source, whereas photochemical reaction is important for 1 O 2 production. Reactivity and biomolecule damage by these ROS depend on the surrounding conditions and targeting molecules. In this chapter, production mechanisms of H 2 O 2 and 1 O 2 , biomolecule oxidation by these ROS, their detection methods, and production control of 1 O 2 are briefly reviewed.

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Section: Protein Oxidation By 1 Omentioning

confidence: 99%

Biomolecules Oxidation by Hydrogen Peroxide and Singlet Oxygen

Hirakawa¹

2018

Reactive Oxygen Species (ROS) in Living Cells

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“…On the other hand, the shorter lifetime species (1.4 ns) supports the quenching of S 1 state of Cl 2 P(V)TPP through the ET from tryptophan residue. Previous reports indicated the ET from the tryptophan residue to the S 1 state of other kinds of P(V)porphyrins [8,9,15]. The reaction mechanism is presented in the Scheme 1.…”

mentioning

confidence: 93%

“…The fluorescence decrement of HSA can be explained by tryptophan oxidation through the photosensitized reaction [8,9]. Protein damage by Cl 2 P(V)TPP was evaluated by measurement of the fluorescence intensity from tryptophan residue as previously reported [8].…”

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confidence: 99%

“…For example, in this research, a synthesized porphyrin, Cl 2 P(V)TPP (Figure1) was used. The protein damage photosensitized by Cl 2 P(V)TPP was examined by the method of the previous reports [8,9]. The sample solution containing 10 μM porphyrin and 10 μM human serum albumin (HSA), a water-soluble protein, in a sodium phosphate buffer (pH 7.6) was irradiated with a light-emitting diode (LED) (519 nm, 1 mW cm -2 , CCS Inc., Kyoto, Japan).…”

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confidence: 99%

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Photosensitized oxidative damage of human serum albumin by water-soluble dichlorophosphorus(V) tetraphenylporphyrin

Ouyang¹,

Hirakawa²

2015

Rapid Communication in Photoscience

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Biomolecular photo-damaging activity of a watersoluble cationic porphyrin was examined using human serum albumin (HSA), a water-soluble protein as a target biomolecule model by a fluorometry. Dichlorophosphorus(V) tetraphenylporphyrin (Cl 2 P(V)TPP), was synthesized and used as a photosensitizer. This porphyrin could bind to HSA and cause the photosensitized oxidation of HSA through the singlet oxygen generation and the oxidative photo-induced electron transfer (ET). Near infrared emission spectroscopy demonstrated the photosensitized singlet oxygen generation by this porphyrin. Decrement of the fluorescence lifetime of Cl 2 P(V)TPP by HSA supported the ET mechanism. Furthermore, the estimated Gibb's energy indicated that the ET mechanism is possible in the terms of energy. Because oxygen concentration in cancer cell is relatively low, ET mechanism is considered to be advantageous for photosensitizer of photodynamic therapy.Porphyrins have been used as the drugs for photodynamic therapy (PDT), which is a less invasive treatment of cancer [1,2]. The oxidation of biomolecules is the major mechanism of PDT. It is triggered by singlet oxygen ( 1 O 2 ) generation or photo-induced electron transfer (ET). Biomolecule oxidation by 1 O 2 is considered as the main mechanism of PDT, however, the low concentration of oxygen in cancer cells restricts the PDT effect [3,4]. Therefore, ET mechanism might become a more important mechanism of PDT in the future. The ET mechanism requires highly oxidative activity (a lower reduction potential) in the photoexcited state of the photosensitizer. Larger excitation energy is advantageous for the lower reduction potential of the photosensitizer in the photoexcited state. Indeed, ultra-violet photosensitizers mainly induce biomolecule photodamage through the ET mechanism, whereas a visible-light photosensitizer is not appropriate for this mechanism [5]. Therefore, an appropriate molecular design to achieve ET mediated biomolecule damage using a visible-light photosensitizer is important. Since highvalent porphyrin complexes demonstrate a lower reduction potential in their photoexcited state than free-base or low-valent metal complexes, these porphyrins are advantageous for the oxidative ET reaction [5][6][7]. For example, in this research, a synthesized porphyrin, Cl 2 P(V)TPP (Figure1) was used.

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“…When a porphyrin enters a living organism, it may combine with a protein such as HSA, and this will control its accumulation, distribution, and metabolism in the body. Therefore, there have been numerous studies on the interaction of porphyrins with HSA …”

Section: Introductionmentioning

confidence: 99%

Synthesis of Tailed Metalloporphyrins Modified with 2‐Chloronicotinic Acid and Interactions with Human Serum Albumin

Wang

Peng

Zhang

et al. 2017

Bulletin Korean Chem Soc

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Two kinds of free‐base tailed porphyrins modified with 2‐chloronicotinic acid and the corresponding Zn porphyrins have been synthesized. They have been characterized by elemental analysis and NMR, UV/Vis, fluorescence spectra, and infrared spectroscopies. Their configurations have been optimized through theoretical calculations. The fluorescence quantum yields were determined by a comparative method. The interactions between the Zn porphyrins and human serum albumin have been studied by means of fluorescence spectra. The experimental results showed that the interaction mechanism involved a combined fluorescence quenching process (static and dynamic quenching) and that the main driving force was hydrophobic in nature. Quenching constants, binding constants, thermodynamic parameters, and binding distances have been determined.

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Determination of Singlet Oxygen and Electron Transfer Mediated Mechanisms of Photosensitized Protein Damage by Phosphorus(V)porphyrins

Cited by 39 publications

References 35 publications

Biomolecules Oxidation by Hydrogen Peroxide and Singlet Oxygen

Biomolecules Oxidation by Hydrogen Peroxide and Singlet Oxygen

Photosensitized oxidative damage of human serum albumin by water-soluble dichlorophosphorus(V) tetraphenylporphyrin

Synthesis of Tailed Metalloporphyrins Modified with 2‐Chloronicotinic Acid and Interactions with Human Serum Albumin

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