Spectrofluorimetric study of the interaction of methyl-parathion with fish serum albumin.
The interaction of methyl-parathion with the albumin of Piaractus mesopotamicus (Holmberg 1887) (= pacu), a fish species typical of Brazilian rivers, was studied and the results compared with known values for human and bovine albumin obtained in an earlier investigation. Methyl-parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous pesticide still used in agriculture and fish farming in many countries. The fluorescence quenching technique with tryptophan as a natural probe was used to detect for the presence of methyl-parathion. Fluorescence can be mathematically expressed by the Stern-Volmer equation to calculate quenching constants, and changes in the behavior of Stern-Volmer curves at different temperatures indicate the nature of the mechanism causing the quenching. Our results indicate that methyl-parathion forms a complex with fish albumin. The estimated association constant is 9.73 x 103 (+/- 4.9 x 102) M(-1) at 25 degrees C.
Silva
Dilson
D
Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil. dilsons@uerj.br.
Cortez-Moreira
Madelayne
M
Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil.
Cunha Bastos
Vera Lúcia Freire
VLF
Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil.
Cunha Bastos
Jayme
J
Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil.
Martins Cortez
Célia
C
Rio de Janeiro State University, Rio de Janeiro, RJ, Brazil.
D000818:Animals; D002417:Cattle; D005399:Fishes / Q000378:metabolism*; D005453:Fluorescence; D006801:Humans; D007306:Insecticides / Q000378:metabolism*; D008743:Methyl Parathion / Q000378:metabolism*; D008954:Models, Biological; D012709:Serum Albumin / Q000378:metabolism*; D013045:Species Specificity; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014364:Tryptophan
D007306:Insecticides; D012709:Serum Albumin; D008743:Methyl Parathion; D014364:Tryptophan