Table 1.

Effect of inhibitors on respiratory activity of cytochrome bd

Inhibitor	Bacterium
	E. coli(a)	B. stearo-thermophilus	A. vinelandii	Photobacterium phosphoreum
KCN or NaCN	2 mM (b) [27]	0.5 mM (e) [68]	-	62 μM (b) [288]
NaN3	400 mM (b) [27]	8.2 mM (e) [68]	-	40 mM (b) [288]
H2O2	120 mM (b) [27]	-	-	-
2-n-heptyl-4-hydroxyquinoline N-oxide (HOQNO)	7 μM (b) [27]	-	5–20 μM (d) [249]	8.2 μM (b) [288]
ZnSO4 or ZnCl2	60 μM (b) [27]	200 μM (e) [68]	-	2.7 μM (b) [288]
Piericidin A	15 μM (b) [27]	-	-	-
Antimicin A	50 μM, 80% (c) [285]	-	11 μM (d) [279,286]	-
Undecylhydroxydioxobenzothiazole (UHDBT)	20 μM, 18% (c) [285]	-	20 μM (d) [279,286]	-
(1,5-Dimethylhexyl)quinazolinamide	100 μM, 88% (c) [285]	-	-	-
(1-Methyldecyl)quinazolinamide	100 μM, 85% (c) [285]	-	-	-
Stigmatellin	200 μM, 14% (c) [285]	-	-	-
Nigericin	100 μM, 44% (c) [285]	-	-	-
Dibromothymoquinone	100 μM, 38% (c) [285]	-	-	-
Aurachin A	700 μM, 27% (c) [285]	-	-	-
Aurachin C	214 nM, 90% (c) [285]	-	-	-
Aurachin D	400 nM, 93% (c) [285]	-	-	-
decyl-aurachin D	-	-	13 nM (d) [249]	-
p-benzoquinone	-	120 μM (e) [68]	-	-
2,6-Dimethyl-p-benzoquinone	-	65 μM (e) [68]	-	-
Nitric oxide (NO)	100 nM (d) [106]	-	100 nM (d) [106]	-
Carbon monoxide (CO)	-	-	0.5–1 mM, 80% (g) [287]	-
Pentachlorophenol (PCP)	200 μM (d) [32]	-	-	-
2-Thenoyl trifluoroacetone (TTFA)	1 mM, 35% (f) [26]	-	-	-
Gramicidin S	5.3 μM (b) [145]	-	-	-

^(a)Data are referred to cytochrome bd-I.

^(b)IC₅₀ for ubiquinol-1 oxidase activity of the purified enzyme.

^(c)Concentration and % inhibition of duroquinol oxidase activity of cytochrome bd-containing membranes.

^(d)Inhibition constant (K_i) for ubiquinol-1 oxidase activity of the purified enzyme.

^(e)IC₅₀ for duroquinol oxidase activity of the purified enzyme.

^(f)Concentration and % inhibition of ubiquinol-1 oxidase activity of the purified enzyme.

^(g)Concentration and % inhibition of ascorbate-2,6-dichlorophenolindophenol oxidase activity of cytochrome bd-containing particles.