Table 1.

Atpenin inhibition of respiratory enzymes in nematode and mammalian mitochondria

Species	Activities	IC50, μM
		Atpenin A4	Atpenin A5	Harzianopyridone
A. suum adult muscle	Complex I + II*	0.11	0.014	1.6
	Complex I†	>100	>100	>100
	Complex II (QFR)‡	0.22	0.012	0.36
	Complex II (SQR)§	0.22	0.032	2
Bovine heart	Complex I + III¶	140	82	420
	Complex II§	0.011	0.0036	0.017
Rat liver	Complex I + III¶	>500	>500	>500
	Complex II§	0.024	0.0037	0.2

^*Measured by NADH-fumarate reductase activity. 

^† Measured by NADH-quinone reductase activity. UQ₁, UQ₂, or decylrhodoquinone was used as electron acceptor. 

^‡ Measured by rhodoquinol-fumarate reductase activity. 

^§ Measured by succinate-UQ reductase activity. 

^¶ Measured by NADH-cytochrome c reductase activity.