"Photo" Chemistry Without Light?

In the early seventies, Giuseppe Cilento (São Paulo University), Emil White (Johns Hopkins University) and Angelo Lamola (AT&T Bell Laboratories) postulated that typical photochemical reactions could occur in dark parts of living organisms if coupled to enzymatic sources of electronically excited products. Their paradoxical hypothesis of "photochemistry without light" was chemically anchored on the synthesis and weak chemiluminescence of several 1,2-dioxetanes, unstable cyclic peroxides whose thermal cleavage produces long-lived and reactive triplet carbonyls. Collisional reactions or energy transfer of triplet species to cellular targets could eventually result in "photo" products that potentially trigger normal or pathological responses. These ideas flourished in the labs of various researchers who attempted to explain the presence and biological roles of "dark" secondary metabolites, including plant hormones, pyrimidine dimers, alkaloid lumi-isomers, protein adducts, and mitochondrial permeators, thereby broadening the field of photobiology.

Bibliographic Details

Main Authors:	Baader,Wilhelm J., Stevani,Cassius V., Bechara,Etelvino J. H.
Format:	Digital revista
Language:	English
Published:	Sociedade Brasileira de Química 2015
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532015001202430
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