Insights into the binding mechanism of Putrescine on α-amylase by multiple spectroscopic techniques and molecular docking

•Interactions between Acid Yellow 1and intestinal protease.•biological functions of Acid Yellow 1for regular consumer.•Investigate the stability, activity, secondary and tertiary conformational changes.•The fluorescence spectroscopy, stern Volmer model for NYS- trypsin complex.•computational study (including docking and MD simulation) for NYS- trypsin complex The interaction between polyamines and enzymes has been extensively studied in recent decades. The aim of this study is to consider the interactions of α-amylase with putrescine to obtain information on how the ligand interacts with the enzyme, study structural and functional changes, determine binding forces, and the stability of the protein at pH 6.9. Numerous spectroscopic procedures incorporate Ultraviolet−Visible spectroscopy, fluorescence spectroscopy, steady-state thermal stability, as well as, molecular docking, were applied. The results of UV-Vis spectrophotometry represented that the intensity of absorbance of α-amylase in attendance of the putrescine was increased. The findings obtained from fluorescence spectroscopy suggest that putrescine has decreased intrinsic fluorescence of α-amylase and tertiary structural change. The thermodynamic and docking analysis showed that the electrostatic forces in compression with hydrogen bond and hydrophobic interaction have been dominant. The quenching mechanism of putrescine was static quenching. The results of the activity assays indicate that putrescine has enhanced enzymatic activity. The docking simulations results supported the experimental findings. According to the results, putrescine could be regarded as an activator ligand with favorable actions on the α-amylase structure and function.