6.2 μM) is reported.[79] Some metal-conjugated and peptidomimetic compounds showed inhibitory activity against 3CLpro.[77] Some of the small molecules also act as an inhibitor that is arylboronic acids, quinolinecarboxylate derivatives, thiophenecarboxylate, and phthalhydrazide-substituted ketoglutamine analogs.[77] Some flavonoids are also reported to inhibit Mpro.[75] GC376 also has protease inhibitor activity.[81] A crystal structure of Mpro with small molecule inhibitor N3 is also reported (PDB ID: