Bovine trypsin is one of the most important enzymes which have many applications. This enzyme is a soluble globular protein that is composed of 223 residues. Disaccharides in the human diet, especially in fruits and vegetables are extraordinary sugars. The great attraction of disaccharides toward digestive proteases in various investigations have pointed out that the interaction of intestinal proteases with disaccharides is considerable. The conformation and activity changes were studied by various experimental and computational methods. UV–Vis spectroscopy results indicate an interaction between maltose and trypsin and forms a protein-ligand complex with certain new conformation. The fluorescence emission spectrum was recorded in the range of 295–400 nm upon excitation at 290 nm. As revealed by the data, trypsin had strong fluorescence with an emission peak at 335 nm due to its Trp residue. When maltose was added into the trypsin solution, the intrinsic fluorescence intensity of trypsin decreases regularly and a small red shift is seen by increasing of maltose concentration. These results suggest that maltose interact with trypsin and cause quench its intrinsic fluorescence. The activity of Trypsin
was decreased in the presence of maltose. The inhibition of trypsin by maltose was mixed. Molecular docking results indicate the presence of one binding site with a negative value for the Gibbs free energy. Dynamic simulation and CD spectroscopy results present that the complex (Try-Mal) become more stable than trypsin alone. generally, maltose act as an inhibitor and dynamic quencher that can change the structure of trypsin.