RP-HPLC reveals the L-cysteine induced degradation of phenylmercuric acetate

Proposed biomolecular mechanism by which PMA targets Cys-residues of the SARS-CoV-2 main protease (M2). • The adverse effects of human exposure to phenylmercury acetate are not understood. • Phenylmercury acetate (PMA) also effectively inhibits SARS-CoV 2. • An RP-HPLC method was employed to study the reaction of L-cysteine with PMA. • A novel Hg-peak eluted which was identified as phenylmercuric cysteinate (PMC). • The mechanism of PMC formation is implicated in the inhibition of SARS-CoV 2.