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Visible Light-Driven O2 Reduction by a Porphyrin-Laccase System.
MedLine Citation:
PMID:  23330664     Owner:  NLM     Status:  Publisher    
Several recent studies have shown that the combination of photosensitizers with metalloenzymes can support a light-driven multi-electron reduction of molecules such as CO2 or HCN. Here we show that the association of the Zn tetramethyl pyridinium porphyrin (ZnTMPyP4+) photosensitizer with the multi-copper oxidase laccase allows to link the oxidation of an organic molecule to the four electrons reduction of dioxygen into water. The enzyme is photoreduced within minutes with porphyrin/enzyme ratio as low as 1/40. With a 1/1 ratio, the dioxygen consumption rate is 2 µmol L-1 s-1. Flash photolysis experiments support the formation of the triplet excited state of ZnTMPyP4+ which reduces the enzyme to form a radical cation of the porphyrin with a kET ≈107 s-1 M-1. The long-lived triplet excited state of the ZnTMPyP4+ (τ0 0.72 ms) accounts for a substantial electron transfer quantum yield ϕET =0.26. Consequently, the enzyme-dependent photo-oxidation of the electron donor (EDTA) occurs with a turn-over of 8 min-1 for the one electron oxidation process, thereby supporting the suitability of such enzyme/sensitizer hybrid material for aerobic photo-driven transformations on substrates. This study is the first example of a phorphyrin-sensitized 4-electron reduction of an enzyme of the multicopper-oxidase family, leading to photoreduction of dioxygen into water.
Theodore Lazarides; Igor V Sazanovich; A Jalila Simaan; Maria Chrisanthi Kafentzi; Milan Delor; Yasmina Mekmouche; Bruno Faure; Marius Réglier; Julia A Weinstein; Athanassios Georgios Coutsolelos; Thierry Tron
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-21
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  -     ISSN:  1520-5126     ISO Abbreviation:  J. Am. Chem. Soc.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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