Introducing rebaudioside A as a novel enzyme stabilizer: comparison with lysine on Aspergillus oryzae alpha-amylase...

The role of amino acids and glycosidic compounds was investigated as edible and potential compatible stabilizing additives against Aspergillus oryzae alpha-amylase (AOA) inactivation and amorphous aggregation.

Glycine (Gly), proline (Pro), lysine (Lys), sucralose, and rebaudioside A were tested across concentrations from 25 mM to 2 M during thermal inactivation of AOA. While amino acids did not affect AOA intrinsic activity at 60 mmol/L, sucralose had a detrimental effect, and rebaudioside A could preserve this activity even at higher concentrations. At 60 mmol/L, all compounds inhibited thermally induced AOA aggregation, with Lys exhibiting a slight advantage among amino acids, and rebaudioside A emerging as the best stabilizer. Atomic force microscopy (AFM) assessed whether the two best compounds, Lys and rebaudioside A, affected the size of aggregates, confirming their impact. Molecular docking identified potential interaction sites between these compounds and AOA, and subsequent molecular dynamics simulations elucidated their effect on parameters such as root mean square deviation (RMSD) and root mean square fluctuation (RMSF), while highlighting the residues dynamically involved in the interaction with these ligands.

This study underscores the potential of rebaudioside A and Lys as effective stabilizing agents for AOA in vitro, with a significant role in decreasing its amorphous aggregates. © 2025 Society of Chemical Industry.