Merbromin (Mercurochrome), a xanthene dye and an antibacterial agent, is the first of a series of antiseptics that contained mercury, also is a mixed-type inhibitor of 3CLpro due to its ability of increasing the KM and decreasing the Kcat of 3CLpro.
Merbromin strongly inhibites the proteolytic activity of 3CLpro which is a promising target for developing anti-SARS-CoV-2 drugs. Michaelis-Menten kinetic analysis shows that Merbromin is a mixed-type inhibitor of 3CLpro, indicating by its ability of increasing the KM and decreasing the Kcat of 3CLpro. And 3CLpro possessed two binding sites for Merbromin.[2]
[1] Chen J, et al. Biochem Biophys Res Commun. 2022 Feb 5;591:118-123. [2] Chen J, et al. Biochem Biophys Res Commun. 2022 Feb 5;591:118-123.