Protein nutritional quality, amino acid profile, anti-amylase and anti-glucosidase properties of microalgae: Inhibition and mechanisms of action through in vitro and in silico studies

Abstract

Since microalgae proteins contain the same amount of protein as conventional protein sources such as soybean, milk, beef, and egg, they are considered as new sources of functional amino acids. In this research, microalgae amino acid extracts were studied for their nutritional value as well as their anti-amylase and anti-glucosidase properties, in vitro and in silico. Essential, non-essential, non-protein, flavor, hydrophobic, aromatic, bitter, and sweet amino acids were found to be equal to or greater than those found in egg protein in the selected microalgae. The anti-amylase and anti-glucosidase properties of amino acid extract were confirmed in this study, but at a lower level than acarbose. Microalgae amino acids inhibited amylase and glucosidase by increasing the Km/Vmax ratio through non-competition and un-competition strategy, according to the kinetic analysis. Molecular docking analysis revealed that microalgae amino acids interact with amino acid residues near the active site of amylase and allosteric sites of glucosidase through p-alkyl interactions, positive-negative interactions, salt bridges, and hydrogen bonds. In conclusion microalgae amino acid not only can be considered as functional food with nutritional quality equal to egg protein, but also due to functional amino acid can be imperative as non-competitive and un-competitive inhibitor of amylase and glucosidase.