Photosynthetic tissues are organized functionally into aggregates of light harvesting pigments (mainly chlorophylls, carotenoids, and phycobilins) associated with photochemical reaction centers (1, 2). The pigments absorb light and deliver the energy to the reaction centers, where an oxido-reductive photochemistry ensues. The primary photoproducts, oxidizing and reducing entities, serve as star...

Starting from the various primary photochemical processes (luminescence, non-radiative transition to the ground state, electron and energy transfer, isomerization, addition, hydrogen abstraction, and fragmentation), the most important technical applications of photochemistry are reviewed. The main applications of luminescence phenomena are optical bleaching of textiles and paper. Rapid radiatio...

The first nucleic acid-directed catalytic photochemical reaction that is induced by nontoxic red light was developed. This reaction is fast, high yielding, sequence specific, and enables one to functionalize an oligonucleotide.

TiO(2) nanoparticles were directly coupled with porous silicon and this novel composite material shows very strong photocatalytic activity for the degradation of Rhodamine B with high photochemical stability under visible light irradiation.

The presence of aromatic residues and their close spatial proximity to disulphide bridges makes hen egg white lysozyme labile to UV excitation. UVB induced photo-oxidation of tryptophan and tyrosine residues leads to photochemical products, such as, kynurenine, N-formylkynurenine and dityrosine and to the disruption of disulphide bridges in proteins. We here report that lysozyme UV induced phot...

The heat, ultraviolet and rihoflavin-sensitized visible inactivations of taka-amylase A are strongly inhibited by the presence of its substrate. The stabilization of the secondary structure of enzyme protein by the conformation change due to the formation of enzyme-substrate and -product complexes is responsible for the protection of enzyme from the heat inactivation. The photoinactivations are...

We explored the short-term adjustment in photochemical efficiency (Fv/Fm) in adult and young leaves of the understory neotropical shrub Psychotria limonensis Krause (Rubiaceae) in response to rapid changes in the light environment. Leaves were collected from 20 individual plants growing under sun and shade conditions on Gigante Peninsula, Barro Colorado Natural Monument (Republic of Panama), du...

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...