Table 3.

The role of vital proteins of host and virus during infection and the possible efficacy of the drugs against SARS-CoV-2.

Proteins to target	The role of viral proteins during hijacking the host cells.	Drugs	Hypothesis to act against SARS-CoV-2	Already tested against diseases	Adverse side effects	References
Viral Genome proteins
RdRp	RNA-dependent RNA polymerase- replicates genome of the virus.	ribavirin and remdesivir	A nucleotide analogue that specifically inhibits replication of virus via blocking nucleotide synthesis of the virus.	Ebola Hepatitis C, RSV infection	Elevated levels of transaminases and renal injury.	[[59], [60], [61], [62], [63]]
PLpro	Papain-like protease- proteolysis viral polyprotein to active viral protein.	lopinavir	Protease inhibitor	For HIV in combination with ritonavir	Nausea, vomiting, gastrointestinal disturbance, pancreatitis, cardiac abnormalities.	[60,62]
3CLpro	Coronavirus protease- proteolysis viral polyprotein to active protein.	lopinavir	Protease inhibitor	HIV in combination with ritonavir	Nausea, vomiting, gastrointestinal disturbance, pancreatitis, cardiac abnormalities.	[60,62]
S protein	Spike protein helps in holding virus to the host ACE2 receptor.	arbidol	Prevents binding of viral S protein to the host cells and blocks its entry.	Influenza	Elevated levels of transaminases, allergic reactions and gastrointestinal disorders.	[[64], [65], [66]]
Host proteins
ACE2	Protein receptor binds with viral S protein allowing virus to enter into the host cells.	arbidol	Prevents binding of S protein to the ACE2 receptor and blocs its entry	Influenza	Elevated levels of transaminases, allergic reactions and gastrointestinal disorders.	[[64], [65], [66]]
TMPRSS2	Protease produced by the host potentiates priming of S protein of the virus, which facilitates binding.	Camostat mesylate	–	–	–	[67]