ArticleProceedings of the National Academy of Sciences of the United States of America2002
Enzymology below 200 K: the kinetics and thermodynamics of the photochemistry catalyzed by protochlorophyllide oxidoreductase.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2002. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 32 papers.
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Who cites it
32 citing papers in PubMed, 93 citations in OpenAlex.
- The structural chemistry and biosynthesis of chlorophylls.RSC chemical biology · 2026Review
- Transitioning enzyme catalysis towards photocatalysis.Philosophical transactions. Series A, Mathematical, physical, and engineering sciences · 2025Review
- How Photoactivation Triggers Protochlorophyllide Reduction: Computational Evidence of a Stepwise Hydride Transfer during Chlorophyll Biosynthesis.ACS catalysis · 2022Article
- Extracellular Vesicle-Mediated Secretion of Protochlorophyllide in the CyanobacteriumPlants (Basel, Switzerland) · 2022Article
- Photocatalysis as the 'master switch' of photomorphogenesis in early plant development.Nature plants · 2021Review
- The Role of Membranes and Lipid-Protein Interactions in the Mg-Branch of Tetrapyrrole Biosynthesis.Frontiers in plant science · 2021Review
- Substrate recognition induces sequential electron transfer across subunits in the nitrogenase-like DPOR complex.The Journal of biological chemistry · 2020Article
- Crystal structures of cyanobacterial light-dependent protochlorophyllide oxidoreductase.Proceedings of the National Academy of Sciences of the United States of America · 2020Article
- Consensus model of a cyanobacterial light-dependent protochlorophyllide oxidoreductase in its pigment-free apo-form and photoactive ternary complex.Communications biology · 2019Article
- COBRAMM 2.0 - A software interface for tailoring molecular electronic structure calculations and running nanoscale (QM/MM) simulations.Journal of molecular modeling · 2018Article
- Multiple active site residues are important for photochemical efficiency in the light-activated enzyme protochlorophyllide oxidoreductase (POR).Journal of photochemistry and photobiology. B, Biology · 2016Article
- Plant Protochlorophyllide Oxidoreductases A and B: CATALYTIC EFFICIENCY AND INITIAL REACTION STEPS.The Journal of biological chemistry · 2015Article
- Broadened Substrate Specificity of 3-Hydroxyethyl Bacteriochlorophyllide a Dehydrogenase (BchC) Indicates a New Route for the Biosynthesis of Bacteriochlorophyll a.The Journal of biological chemistry · 2015Article
- Evolutionary Aspects and Regulation of Tetrapyrrole Biosynthesis in Cyanobacteria under Aerobic and Anaerobic Environments.Life (Basel, Switzerland) · 2015Review
- Excited-state charge separation in the photochemical mechanism of the light-driven enzyme protochlorophyllide oxidoreductase.Angewandte Chemie (International ed. in English) · 2015Article
- Iron-sulfur cluster-dependent catalysis of chlorophyllide a oxidoreductase from Roseobacter denitrificans.The Journal of biological chemistry · 2015Article
- Dark-operative protochlorophyllide oxidoreductase generates substrate radicals by an iron-sulphur cluster in bacteriochlorophyll biosynthesis.Scientific reports · 2014Article
- The photoinitiated reaction pathway of full-length cyanobacteriochrome Tlr0924 monitored over 12 orders of magnitude.The Journal of biological chemistry · 2014Article
- Article
- Mechanistic reappraisal of early stage photochemistry in the light-driven enzyme protochlorophyllide oxidoreductase.PloS one · 2012Article
Corrections and comments
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Authors and funding
4 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The chlorophyll biosynthesis enzyme protochlorophyllide reductase (POR) catalyzes the light-dependent reduction of protochlorophyllide (Pchlide) into chlorophyllide in the presence of NADPH. As POR is light-dependent, catalysis can be initiated by illumination of the enzyme-substrate complex at low temperatures, making it an attractive model for studying aspects of biological proton and hydride transfers. The early stages in the photoreduction, involving Pchlide binding and an initial photochemical reaction, have been studied in vitro by using low-temperature fluorescence and absorbance measurements. Formation of the ternary POR-NADPH-Pchlide complex produces red shifts in the fluorescence and absorbance maxima of Pchlide, allowing the dissociation constant for Pchlide binding to be measured. We demonstrate that the product of an initial photochemical reaction, which can occur below 200 K, is a nonfluorescent intermediate with a broad absorbance band at 696 nm (A696) that is suggested to represent an ion radical complex. The temperature dependence of the rate of A696 formation has allowed the activation energy for the photochemical step to be calculated and has shown that POR catalysis can proceed at much lower temperatures than previously thought. Calculations of differences in free energy between various reaction intermediates have been calculated; these, together with the quantum efficiency for Pchlide conversion, suggest a quantitative model for the thermodynamics of the light-driven step of Pchlide reduction.
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