RESUMO
Polycyclic aromatic hydrocarbons are environmental pollutants with strong carcinogenicity, indirect teratogenicity, and mutagenicity. This study explored the interaction mechanism of benzo(a)pyrene with free DNA in vitro by using various analytical methods. UV-vis spectra showed that benzo(a)pyrene and DNA formed a new benzo(a)pyrene-DNA complex. The thermal melting temperature of DNA increased by 12.7 °C, showing that the intercalation of benzo(a)pyrene into DNA could promote the stability of the DNA double helix structure. The intercalation of benzo(a)pyrene with DNA in vitro was further confirmed by fluorescence microscopy with magnetic beads. Fluorescence spectra showed that the interaction between DNA and benzo(a)pyrene decreased the fluorescence intensity of benzo(a)pyrene, and the maximum quenching rate was 27.89%. The quenching mode of benzo(a)pyrene was static quenching. Thermodynamic data showed that the main driving forces were van der Waals forces and hydrogen bonds, and the reaction was spontaneous. The results of this study provided a novel insight for the establishment of polycyclic aromatic hydrocarbon capture and elimination through polycyclic aromatic hydrocarbon-DNA intercalation.
Assuntos
Benzo(a)pireno/química , DNA/química , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Benzo(a)pireno/análise , Carbono/química , Fenômenos Químicos , Dicroísmo Circular , Poluentes Ambientais/química , Ligação de Hidrogênio , Conformação de Ácido Nucleico , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Análise Espectral , Termodinâmica , Temperatura de TransiçãoRESUMO
In pH 6.5 phosphate buffer solutions, dodecyl benzene sulfonate (SDBS) was combined with casein to form association particles, which exhibited five Rayleigh scattering peaks at 470, 360, 400, 420 and 520 nm, respectively. Under suitable conditions, papain has catalytic effect on the hydrolysis of casein, and SDBS can stop the catalytic reaction and be combined with the excess casein to form association particles. The scattering peak at 470 nm decreased with the activity of papain. The delta I470 value was linear with the papain activity in the range of 0.048-4.8 USP x mL(-1). Its regress equation is delta I(SDBS) = 1.972c + 2.31, with a related coefficient of 0.9999 and detection limit of 0.020 USP x mL(-1). This new assay has been applied to the assay of the papain activity in food additive with satisfactory results.