scholarly journals Electron Transfer Initiated Reactions Photoinduced by Pterins

Pteridines ◽  
2011 ◽  
Vol 22 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Carolina Lorente ◽  
Gabriela Petroselli ◽  
M. Laura Dántola ◽  
Esther Oliveros ◽  
Andrés H. Thomas
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Redox Reactions ◽  
Type I ◽  
Biological Processes ◽  
Type Ii ◽  
Triplet Excited State ◽  
Oxygen Production ◽  
Production Type ◽  
Transfer Mechanisms

Abstract Interest in the photochemistry and photophysics of pterins has increased since the participation of this family of compounds in different photobiological processes has been suggested or demonstrated in recent decades. Pterins participate in relevant biological processes, such as metabolic redox reactions, and can photoinduce the oxidation of biomolecules through both electron transfer mechanisms (Type I) and singlet oxygen production (Type II). This article describes recent findings on electron transfer-initiated reactions photoinduced by the triplet excited state of pterins and connects them in the context of photosensitized processes of biological relevance.

Ground- and excited-state interactions of 2,7,12,17-tetraphenylporphycene with model target biomolecules for type-I photodynamic therapy

2009 ◽  
Vol 13 (01) ◽  
pp. 99-106 ◽  
Author(s):  
Noemí Rubio ◽  
Víctor Martínez-Junza ◽  
Jordi Estruga ◽  
José I. Borrell ◽  
Margarita Mora ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photodynamic Therapy ◽  
Excited State ◽  
Singlet Oxygen ◽  
Cell Lines ◽  
Mechanism Of Action ◽  
Photophysical Properties ◽  
Type I ◽  
Type Ii ◽  
Hydrophobic Compound

Biosubstrate-sensitizer binding is one of the factors that enhances the type-I mechanism over the type-II in the whole photodynamic process. 2,7,12,17-Tetraphenylporphycene (TPPo), a second-generation photosensitizer, is a hydrophobic compound with good photophysical properties for photodynamic therapy applications that has proved its ability for the photoinactivation of different cell lines. Nevertheless, little is known about its mechanism of action. This paper focuses on the study of the interaction/binding of TPPo with different model biomolecules that may favor the type-I mechanism in the overall photodynamic process, including nucleosides, proteins, and phospholipids. Compared with more hydrophilic photosensitizers, it is concluded that TPPo is more likely to undergo type-II (singlet oxygen) than type-I (electron transfer) photodynamic processes in biological environments.

scholarly journals CLEAR AS MUD: THE TYPE I/TYPE II MODEL FOR DEATH RECEPTOR-INDUCED APOPTOSIS

2006 ◽  
Vol 43 (2) ◽  
Author(s):  
David Michael Conrad
Keyword(s):  
Death Receptor ◽  
Mitochondrial Pathway ◽  
Type I ◽  
Biological Processes ◽  
Type Ii ◽  
Type Ii Cell ◽  
Mort Cellulaire ◽  
Induced Apoptosis ◽  
First Time ◽  
The Relationship

Apoptosis is a highly organized form of cell death that plays an important regulatory role in many biological processes. The relationship between the two classical signalling pathways of apoptosis, the “death receptor” and “mitochondrial” pathways, was only vaguely appreciated until 1998, when death receptor pathway-mediated activation of the mitochondrial pathway was clearly demonstrated for the first time. The “type I/type II” model of death receptor-mediated apoptosis was proposed and subsequently adopted for use in categorizing cells according to the involvement of the mitochondrion duringdeath receptor-induced apoptosis. Since that time, however, different interpretations of the type I/type II cell definition have appeared in the literature and, consequently, the meaning of type I and type II cells has become less clear.L’apoptose est une forme de mort cellulaire très structurée qui joue un rôle important de régulation dans un grand nombre de processus biologiques. La relation entre les deux voies de signalisation traditionnelles de l’apoptose, la voie des « récepteurs de mort » et la voie mitochondriale, n’était connue que vaguement avant 1998, l'année où l’activation de la voie mitochondriale par l’intermédiaire de la voie des récepteurs de mort a été clairement démontrée pour la première fois. Le modèle « type I / type II » d’apoptose par l’intermédiaire des récepteurs de mort a été proposé puis adopté auxfins de catégorisation des cellules en fonction de la participation des mitochondries à cette apoptose. Depuis, différentes interprétations ont toutefois été formulées dans des ouvrages scientifiques quant à la définition des cellules de type I et de type II et, par conséquent, la signification de « cellules de type I » et de « cellules de type II » est devenue moins évidente.

Exclusive triplet electron transfer leading to long-lived radical ion-pair formation in an electron rich platinum porphyrin covalently linked to fullerene dyad

2020 ◽  
Vol 56 (45) ◽  
pp. 6058-6061 ◽  
Author(s):  
Dili R. Subedi ◽  
Habtom B. Gobeze ◽  
Yuri E. Kandrashkin ◽  
Prashanth K. Poddutoori ◽  
Art van der Est ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Ion Pair ◽  
Pair Formation ◽  
Triplet Excited State ◽  
Ion Pair Formation ◽  
Donor Acceptor ◽  
Platinum Porphyrin ◽  
Covalently Linked ◽  
Pair Energy

Radical ion-pair energy as high as 1.48 eV with lifetime as much as ∼1 μs, exclusively from the triplet excited state of a photosensitizer, is established in a novel donor–acceptor conjugate.

Electron transfer from the benzophenone triplet excited state directs the photochemical synthesis of gold nanoparticles

2014 ◽  
Vol 13 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Christopher D. McTiernan ◽  
Emilio Isaac Alarcon ◽  
Geniece L. Hallett-Tapley ◽  
Juliana Murillo-Lopez ◽  
Ramiro Arratia-Perez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Excited State ◽  
Photochemical Synthesis ◽  
Triplet Excited State

Competitive Marcus-Type Electron Transfer and Energy Transfer from the Higher Triplet Excited State

2004 ◽  
Vol 108 (50) ◽  
pp. 10941-10948 ◽  
Author(s):  
Masanori Sakamoto ◽  
Xichen Cai ◽  
Michihiro Hara ◽  
Sachiko Tojo ◽  
Mamoru Fujitsuka ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Excited State ◽  
Triplet Excited State

The unquenched triplet excited state of the fluorescent OFF/ON Bodipy-derived molecular probe based on photo-induced electron transfer

2016 ◽  
Vol 15 (11) ◽  
pp. 1358-1365 ◽  
Author(s):  
Zafar Mahmood ◽  
Jianzhang Zhao
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Triplet State ◽  
Molecular Probe ◽  
Singlet Excited State ◽  
Triplet Excited State ◽  
Photo Induced Electron Transfer

Different from the singlet excited state (fluorescence), the triplet state of the probes is not quenched by photo-induced electron transfer.

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