COVID-19(9) Protein(6) in vitro(6) approach(6) Severe acute respiratory syndrome(6) respiratory(6) protease(6) Papain-like protease(6) binding(6) pandemic(6) coronavirus 2(6) PLPro(6) SARS-CoV-2(6) cysteine(4) receptor(3) target proteins(3) global public health(3) coronavirus disease(3) Viral mutations(3) cytotoxic(3) RNA-dependent RNA polymerase(3) proteolytic activity(3) Coronavirus disease 2019(3) Polyanion(3) fenoprofen(3) 3C–like cysteine main protease(3) decrease(3) inhibited(3) shown(3) host cell(3)