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[Light activation of NADH and NADPH]
Biokhimiia (Moscow, Russia)
|January 1, 1978
Summary
UV light reduces ferredoxin and methyl-viologen using NADH and NADPH. Hematoporphyrin and chlorophyll can photosensitize these reactions, enabling hydrogen evolution from NADH and NADPH.
Area of Science:
- Biochemistry
- Photochemistry
- Bioenergetics
Context:
- Nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) are crucial redox coenzymes.
- Their photochemical properties and redox potential modulation are key to understanding biological electron transfer.
- Investigating photosensitization extends the spectral range of these reactions.
Purpose:
- To investigate the photochemical reduction of electron acceptors by NADH and NADPH.
- To explore the photosensitizing effects of hematoporphyrin, chlorophyll, and chloroplasts on these reactions.
- To determine the impact of light excitation on the redox potentials of NADH and NADPH.
Summary:
- UV illumination of NADH and NADPH reduced ferredoxin and methyl-viologen, forming cation-radicals and dihydrodipyridyl.
- Hematoporphyrin photosensitized NADH oxidation by ferredoxin and methyl-viologen into the visible spectrum.
- Light excitation increased NADH and NADPH redox potentials, facilitating hydrogen evolution with bacterial hydrogenase, sensitizable by chlorophyll or chloroplasts.
Impact:
- Demonstrates novel photochemical pathways for redox coenzymes.
- Expands the understanding of photosensitization in biological redox reactions.
- Highlights potential for visible-light-driven hydrogen production using biological catalysts.