Non-transfected (–) and transfected (+) 293T whole cell extracts (30 μg) were separated by 12% SDS-PAGE, and the membrane was blotted with SARS-CoV-2 (COVID-19) 3CLpro (nsp5) antibody (GTX135470) diluted at 1:5000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.