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PHOTOINACTIVATION OF ENZYMES BY LINEAR AND ANGULAR FUROCOUMARINS
Author(s) -
Veronese F. M.,
Schiavon O.,
Bevilacqua R.,
Bordin F.,
Rodighiero G.
Publication year - 1982
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1982.tb04335.x
Subject(s) - furocoumarins , psoralen , furocoumarin , chemistry , enzyme , ribonuclease , biochemistry , dehydrogenase , photochemistry , dna , rna , gene
Furocoumarins with linear (psoralen, 8‐methylpsoralen, 8‐methoxypsoralen and 3‐carbethox‐ypsoralen) and angular molecular structures (angelicin and 4,5'‐dimethylangelicin) were found to inactivate enzymes to different extents through UV‐A irradiation. Moreover, enzymes with different structures (glutamate dehydrogenase, lysozyme, 6‐phosphogluconate dehydrogenase, enolase, thermoly‐sine and ribonuclease) are inactivated to different extents by the same furocoumarin. UV‐A irradiation produces both covalent incorporation of the furocoumarins into the protein molecule and photodegra‐dation of amino acid residues; the latter phenomenon seems to be mainly responsible for the photoinactivation process. A close correlation was found between the capacity of the furocoumarins to photoinactivate enzymes and their capacity to modify free amino acids. A study of the effects of quenchers of various forms of activated oxygen on the photoinactivation of glutamate dehydrogenase, used as a model enzyme, and psoralen and 8‐methylpsoralen as a reference for furocoumarins, showed that singlet oxygen is the species most involved in the photoinactivation process.