RESUMO
The effect of power, time and temperature of ultrasound on the structure of ß-conglycinin (7S) and glycinin (11S), and on the antioxidant activity of their hydrolysates were investigated. All ultrasound treated 7S and 11S fractions showed an increase in the α-helix and ß-turn proportions, and a decrease in ß-sheet and random coil proportions. The polarity of 7S and 11S microenvironment increased after ultrasound treatment. Ultrasound treatment significantly increased the reduction capacity and iron chelating capacity of 7S and 11S hydrolysates. The degree of hydrolysis and free SH groups of 7S and 11S hydrolysates increased after ultrasound pre-treatment. The relative content of high molecular weight peptides reduced, and the relative content of low molecular weight peptides increased in ultrasound treated 7S and 11S hydrolysates. The ultrasonication exposed certain groups of 7S and 11S fractions, improved contact with enzymes, and increased the content of highly active soybean antioxidant peptides.
Assuntos
Antígenos de Plantas/química , Antioxidantes/metabolismo , Globulinas/química , Glycine max/química , Extratos Vegetais/química , Proteínas de Armazenamento de Sementes/química , Proteínas de Soja/química , Ultrassom , Antígenos de Plantas/efeitos da radiação , Antioxidantes/análise , Globulinas/efeitos da radiação , Oxirredução , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/efeitos da radiação , Proteínas de Armazenamento de Sementes/efeitos da radiação , Proteínas de Soja/efeitos da radiação , TemperaturaRESUMO
The effects of exposure to a 50 Hz magnetic field (maximum of 41.7 to 43.6 mT) on the membrane protein structures of living HeLa cells were studied using attenuated total reflection infrared spectroscopy. One min of such exposure shifted peak absorbance of the amide I band to a smaller wave number, reduced peak absorbance of the amide II band, and increased absorbance at around 1600 cm(-1). These results suggest that exposure to the ELF magnetic field has reversible effects on the N-H inplane bending and C-N stretching vibrations of peptide linkages, and changes the secondary structures of alpha-helix and beta-sheet in cell membrane proteins.