Table 2.

Structure and mechanism of hRR inhibitors.

Structure	Name	Cellular Mechanism	RR Subunit Targeted	Mechanism of RR Inhibition
	Tezacitabine	Interferes with DNA synthesis and repair mechanisms	hRRM1	Irreversibly modifies the C-site
	2′-deoxy-2′-methylenecytidine (DMDC)	Interferes with DNA synthesis and repair mechanisms	hRRM1	Inhibits the C-site
	Triapine	Metal chelation	hRRM2	Chelates FeIII from the radical center
	Caracemide	Radical Scavenger	hRRM1	Quenches the radical center
	COH29	Interferes with DNA synthesis and repair mechanisms	hRRM2	Binds hRRM2 near the C-terminal tail to prevent association with hRRM1
	Didox	Radical Scavenger	hRRM2	Chelates FeIII from the radical center
	Trimidox	Radical Scavenger	hRRM2	Chelates FeIII from the radical center
	Gallium nitrate	FeIII mimic	hRRM2	Interferes with FeIII radical center
	Gallium maltolate	FeIII mimic	hRRM2	Interferes with FeIII radical center
	Motexafin gadolinium	FeIII mimic	hRRM2	Interferes with FeIII radical center
	GTI-2040	antisense ologonucleotide	hRRM2	Inhibits hRRM2
	GTI-2501	antisense ologonucleotide	hRRM2	Inhibits hRRM2
	CALAA-01	siRNA-containing nanoparticle	hRRM2	Inhibits hRRM2