THE α-CHYMOTRYPSIN EFFECT ON VARIOUS 9-AMINOACRIDINE FLUORESCENT PROBE EMISSION

Autor: Alain Marty, Madeleine Bourdeaux, Monique Dell' Amico, Pierre Viallet
Rok vydání: 1984
Předmět:
Zdroj: Photochemistry and Photobiology. 40:175-183
ISSN: 0031-8655
DOI: 10.1111/j.1751-1097.1984.tb04572.x
Popis: The influence of a-chymotrypsin upon the fluorescence of various 9-aminoacridine derivatives was examined. Fluorescence is quenched in the presence of this protein. Moreover, quenching is suppressed by the coexistence of hydrocinnamic acid, a competitive inhibitor of the enzyme activity. This leads us to conclude that there is a fluorescent complex formation between protein and fluorophores. Then, the apparent association constants were calculated and the florescence lifetimes of “free” and “bound” 9-aminoacridine were determined by phase-modulation fluorometry. It is deduced that 9-aminoacridine compounds are probably located in the enzymatic active site and that the fluorescence quenching is not due to specific interactions with amino acid residues but is a consequence of the characteristics of this binding site, in particular its hydrophobicity and polarity. Alternatively, when these fluorescent probes are located in the vicinity of some aromatic amino acids (histidin, tryptophan and tyrosin), then the production of non fluorescent complex takes place. It is concluded that 9-aminoacridine compounds can be used for the determination of the type of amino acid residues in the binding sites of proteins.
Databáze: OpenAIRE