Exploration of the structural mechanism of hydrogen (H2)-promoted horseradish peroxidase (HRP) activity via multiple spectroscopic and molecular dynamics simulation techniques

Horseradish peroxidase (HRP) is an enzyme that is widely used in various fields. In this study, the effects of molecular hydrogen (H 2 ) on the activity and structural characteristics of HRP were investigated by employing multiple spectroscopic techniques , atomic force microscopy (AFM) and molecular dynamics (MD) simulations. The results demonstrated that H 2 could enhance HRP activity, especially in 1.5 mg/L hydrogen-rich water (HRW). The structural analysis results showed that H 2 might alter HRP activity by affecting the active sites, secondary structure , hydrogen bonding network, C S groups, and morphological characteristics . The MD results also confirmed that H 2 could increase the Fe N bond distance in the active site, affect the secondary structure, and increase the number of hydrogen bonds . The MD results further suggested that H 2 could increase the number of salt bridges, and lengthen the S S bonds in HRP. This study primarily revealed the mechanism by which H 2 enhances the HRP activity, providing insight into the interactions between gas and macromolecular proteins. However, some of the results obtained via MD simulations still need to be verified experimentally. In addition, our study also provided a new convenient strategy to enhance enzyme activity .