TY - JOUR
T1 - The effect of ΔμH+ on the interaction of rotenone with Complex I of submitochondrial particles
AU - Kotlyar, Alexander B.
AU - Gutman, Menachem
PY - 1992/12/7
Y1 - 1992/12/7
N2 - The inhibition by rotenone of the forward (NADH-oxidase) and reverse (ΔμH+-dependent succinate-NAD+ reductase activities of submitochondrial vesicles was measured. The inhibition of NADH-oxidase, measured in the presence of uncoupler, followed a monophasic inhibition curve with Ki ≤ 2 nM. The reverse electron flow was only partially (40%) inhibited at these rotenone concentrations. The rest of the activity was less sensitive to the inhibitor (Ki ≈ 30 nM). The lower affinity for the inhibitor of the reverse electron flow is a consequence of enhanced rate of rotenone dissociation caused by the high ΔμH+ value required for this reaction. The analysis of the results indicates that the AS-SMP preparation consists of two subpopulations: one with a relatively low degree of coupling, which exhibits high sensitivity to rotenone and the other which is highly coupled with lower affinity to the inhibitor.
AB - The inhibition by rotenone of the forward (NADH-oxidase) and reverse (ΔμH+-dependent succinate-NAD+ reductase activities of submitochondrial vesicles was measured. The inhibition of NADH-oxidase, measured in the presence of uncoupler, followed a monophasic inhibition curve with Ki ≤ 2 nM. The reverse electron flow was only partially (40%) inhibited at these rotenone concentrations. The rest of the activity was less sensitive to the inhibitor (Ki ≈ 30 nM). The lower affinity for the inhibitor of the reverse electron flow is a consequence of enhanced rate of rotenone dissociation caused by the high ΔμH+ value required for this reaction. The analysis of the results indicates that the AS-SMP preparation consists of two subpopulations: one with a relatively low degree of coupling, which exhibits high sensitivity to rotenone and the other which is highly coupled with lower affinity to the inhibitor.
KW - (Bovine heart mitochondrion)
KW - Electron transfer
KW - NADH-ubiquinone reductase
KW - Respiratory chain
KW - Rotenone inhibition
UR - http://www.scopus.com/inward/record.url?scp=0026479943&partnerID=8YFLogxK
U2 - 10.1016/0005-2728(92)90006-N
DO - 10.1016/0005-2728(92)90006-N
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AN - SCOPUS:0026479943
SN - 0005-2728
VL - 1140
SP - 169
EP - 174
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
IS - 2
ER -