Potential toxicity of sarafloxacin to catalase: Spectroscopic, ITC and molecular docking descriptions

The interaction mechanism of sarafloxacin with catalase (CAT) was investigated by combining spectroscopic methods, isothermal titration microcalorimetry (ITC) and molecular docking. Sarafloxacin binds into α-helix area (between Leu 158.A-Lys 168.A and Asp 179.A-Glu 190.A) of CAT mainly through hydrophobic forces. The binding alters the secondary structure of the enzyme, induces variation of the peripheral substituents on the porphyrin ring of heme and leads to the inhibition of CAT activity. The change in the relative position of His 74 to heme induced by the alteration on the secondary structure of CAT is considered to be the key factor for the reduction of the enzyme activity.