Insights into the interaction mechanism of acid phosphatase from Lateolabrax japonicus livers and rosmarinic acid using multispectroscopy and molecular docking

Acid phosphatase (ACP) is a key enzyme that hydrolyzes inosinic acid. The mechanisms underlying the interaction between rosmarinic acid (RA) and ACP and the inhibition of the enzyme were investigated using inhibition kinetics, UV-visible and fluorescence spectroscopy, circular dichroism, and molecular docking. The results showed that RA was a reversible inhibitor of ACP and that the inhibition mechanism was uncompetitive. The ACP fluorescence was quenched by RA, and the quenching mode was static. The interaction of ACP with RA was driven by H bonds and van der Waals forces. The addition of RA increased the α-helix content and decreased the β-sheet, β-turn, and random coil contents in ACP, thereby altering the secondary structure of the enzyme. This study enriched our understanding of inhibitory and interaction mechanisms involving ACP and RA.