Biological Polymers Related to Catechol. Epr and Ir Studies of Melanin, Tannin, Lignin, Humic Acid and Hydroxyquinones
Year: 1964
Type: report
Abstract: have been observed: (a) Photoproduction of C./sup +/ in solution in the absence of added electron acceptors. This is a low quantum yield reaction which proceeds via the lowest excited singlet state. Bacteriochlorophyll also undergoes this reaction, whereas pheophytin does not. (b) One-electron phototransfer between the chlorophyll lowest triplet state and quinones to yield a radical pair (C./sup +/ - Q./sup +/). This may either recombine or separate. The C./sup +/ formed upon separation is unstable and reacts with hydroxylic compounds to regenerate chlorophyll. The Q./sup -/ species partly reacts with oxidized solvent and partly disproportionates. Both bacteriochlorophyll and pheophytin are also able to react with quinones in this manner. The quenching of the chlorophyll lowest singlet state by quinones does not, however, lead to detectable radical formation. These reactions seem to provide acceptable models for certain aspects of photosynthetic energy conversion, and thus elucidation of their detailed mechanisms should lead to useful insights into the nature of the biological process.
DOI: 10.2172/4574981
Authors: C Steelink, G Tollin
Institution: University of Arizona
Language: English
Subfield: Biophysics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1548814904