Z-LVG-CHN2 is a cell-permeable and irreversible inhibitor of cysteine proteinase . Z-LVG-CHN2 is a tripeptide derivative and mimics part of the human cysteine proteinase-binding center. Z-LVG-CHN2 displays an inhibition on HSV whereas no significant effect on poliovirus replication. Z-LVG-CHN2 effectively blocks SARS-COV-2 replication ( EC 50 =190 nM) via inhibition of SARS-COV-2 3CL pro protease.