Inhibition of myocardial rotenone-insensitive NADH cytochrome c reductase by amphiphilic compounds

1984 ◽  
Vol 247 (6) ◽  
pp. H889-H894
Author(s):  
F. F. Kennett ◽  
T. E. Knauer ◽  
K. Owens ◽  
W. B. Weglicki
Keyword(s):  
Cytochrome C ◽  
Critical Micellar Concentration ◽  
Cytochrome C Reductase ◽  
Chain Acyl ◽  
Order Of Magnitude ◽  
Lipid Metabolites ◽  
Nadh Cytochrome ◽  
Coa Thioesters ◽  
Long Chain

Because myocardial ischemia is correlated with both an elevation of intracellular levels of amphiphilic lipid metabolites and a decrease in the rotenone-insensitive NADH cytochrome c reductase (RINCR), we investigated the effects in vitro of some amphiphilic lipid metabolites and synthetic detergents on the activity of RINCR-enriched subfractions of microsomes from isolated cardiac myocytes. RINCR activity was unaffected in vitro by the addition of lysophosphatidylethanolamine (up to 0.5 mM) but was inhibited (maximum 63%) by lysophosphatidylcholine (8 microM). Palmitoyl carnitine (up to 2 mM) was ineffective, but the coenzyme A thioesters of palmitate, stearate, oleate, and arachidonate were inhibitory at concentrations (less than 3 microM) below their critical micellar concentrations. Arachidonyl CoA was approximately one order of magnitude more inhibitory than the other long-chain acyl CoA thioesters. Kinetic analyses revealed the effect of arachidonyl CoA on RINCR activity to be exclusively an alteration of the Vmax with no change in the Km for cytochrome c. The inhibition of myocytic RINCR activity by long-chain acyl CoA may be unrelated to the bulk-phase detergency of this lipid amphiphile since the effects were observed at concentrations below the critical micellar concentration, and other lipid amphiphiles had no effect on RINCR activity. Inhibition of microsomal RINCR activity may result from localized disruption of the membrane microenvironment of the enzyme complex by penetration or dissolution of long-chain acyl CoA into the membrane. The pronounced sensitivity of myocytic RINCR activity to long-chain acyl CoA suggests a relationship between the decreased RINCR activity and the increased levels of this class of lipid metabolites observed in the ischemic myocardium.

Thyroxine stimulation of rat liver microsomal NADH-cytochrome c reductase in vitro

Life Sciences ◽  
1974 ◽  
Vol 15 (12) ◽  
pp. 2059-2068 ◽  
Author(s):  
Fred H. Faas ◽  
William J. Carter ◽  
James O. Wynn
Keyword(s):  
Cytochrome C ◽  
Rat Liver ◽  
Cytochrome C Reductase ◽  
Nadh Cytochrome ◽  
Stimulation Of

scholarly journals Properties of a cytochrome c-enriched light particulate fraction isolated from the photosynthetic bacterium Rhodopseudomonas spheroides

1978 ◽  
Vol 174 (1) ◽  
pp. 267-275 ◽  
Author(s):  
J Barrett ◽  
C N Hunter ◽  
O T G Jones
Keyword(s):  
Cytochrome C ◽  
Sodium Dodecyl ◽  
Photosynthetic Bacterium ◽  
Particulate Fraction ◽  
Cytochrome C Reductase ◽  
Cytochrome C2 ◽  
Succinate Cytochrome C Reductase ◽  
Bulk Membrane ◽  
Nadh Cytochrome ◽  
Rhodopseudomonas Spheroides

Differential centrifugation of suspensions of French-press-disrupted Rhodopseudomonas spheroides yielded a light particulate fraction that was different in many properties from the bulk membrane fraction. It was enriched in cytochrome c and had a low cytochrome b content. When prepared from photosynthetically grown cells this fraction had a very low specific bacteriochlorophyll content. The cytochrome c of the light particles differed in absorption maxima at 77K from cytochrome c2 attached to membranes; there was pronounced splitting of the alpha-band, as is found in cytochrome c2 free in solution. Potentiometric titration at A552–A540 showed the presence of two components that fitted an n = 1 titration; one component had a midpoint redox potential of +345mV, like cytochrome c2 in solution, and the second had E0′ at pH 7.0 of +110 mV, and they were present in a ratio of approx. 2:3. Difference spectroscopy at 77K showed that the spectra of the two components were very similar. More of a CO-binding component was present in particles from photosynthetically grown cells. Light membranes purified by centrifugation on gradients of 5–60% (w/w) sucrose retained the two c cytochromes; they contained no detectable succinate-cytochrome c reductase or bacteriochlorophyll and very little ubiquinone, but they contained NADH-cytochrome c reductase and some phosphate. Electrophoresis on sodium dodecyl sulphate/polyacrylamide gels showed that the light membranes of aerobically and photosynthetically grown cells were very similar and differed greatly from other membrane fractions of R. spheroides.

Endoplasmic reticulum membrane isolated from small-intestinal epithelial cells: enzyme and protein components

1981 ◽  
Vol 52 (1) ◽  
pp. 215-222
Author(s):  
M. Fujita ◽  
H. Ohta ◽  
T. Uezato
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Cytochrome C ◽  
Endoplasmic Reticulum Membrane ◽  
Dependent Manner ◽  
Cytochrome C Reductase ◽  
Basolateral Membranes ◽  
Nadh Cytochrome ◽  
Protein Components ◽  
A Minor

Endoplasmic reticulum membrane-rich fraction was obtained by subfractionation of the light microsomes from mouse jejunal mucosal epithelial cells. It was marked by high glucose-6-phosphatase, NADPH-cytochrome c reductase, and NADH-cytochrome c reductase activities and low Na+,K+-ATPase activity. The enrichment of Na+,K+-ATPase was 180-fold higher in the basolateral membranes than in the endoplasmic reticulum membrane-rich fraction relative to glucose-6-phosphatase. The protein peak that was phosphorylated in a Na-dependent manner was prominent in the basolateral membranes while it was a minor peak in the endoplasmic reticulum membrane-rich fraction. Under the electron microscope the fraction was seen to be composed of homogeneous small vesicles with thin smooth membranes.

Ferrocyanide-activated NADH cytochrome c reductase from barley

1980 ◽  
Vol 18 (4) ◽  
pp. 389-393 ◽  
Author(s):  
Ian S. Small ◽  
John L. Wray
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Reductase ◽  
Nadh Cytochrome

Brain Regional Analysis of NADH-Cytochrome C Reductase Activity in Alzheimerʼs Disease

1990 ◽  
Vol 49 (3) ◽  
pp. 206-214 ◽  
Author(s):  
GEORGE S. ZUBENKO ◽  
JOHN MOOSSY ◽  
DIANA CLAASSEN ◽  
A. Julio Martinez ◽  
GUTTI R. RAO
Keyword(s):  
Cytochrome C ◽  
Reductase Activity ◽  
Regional Analysis ◽  
Cytochrome C Reductase ◽  
Nadh Cytochrome

Acute inhibition of respiratory capacity of muscle reduces peak oxygen consumption

1990 ◽  
Vol 259 (6) ◽  
pp. C889-C896 ◽  
Author(s):  
R. M. McAllister ◽  
R. L. Terjung
Keyword(s):  
Oxygen Consumption ◽  
Electron Transport ◽  
Cytochrome C ◽  
Peak Oxygen Consumption ◽  
Dependent Manner ◽  
Cytochrome C Reductase ◽  
Energy Demands ◽  
Hindlimb Muscle ◽  
Nadh Cytochrome

Electron transport capacity of skeletal muscle was inhibited in situ in an acute dose-dependent manner with myxothiazol, a tight-binding inhibitor of ubiquinone-cytochrome c reductase, complex III of the respiratory chain. Peak oxygen consumption of rat hindlimb muscle was determined via consecutive 10-min isometric contraction (100 ms at 100 Hz) periods of increasing energy demands (4, 8, 15, 30, 45, and 60 tetani/min), using an isolated hindlimb preparation perfused with a high oxygen delivery (approximately 6-8 mumol.min-1.g-1). Peak oxygen consumption decreased from 4.61 +/- 0.19 mumol.min-1.g-1 (control) in a dose-dependent manner to 0.73 +/- 0.07 mumol.min-1.g-1 at 0.50 microM myxothiazol in blood. Oxygen extraction decreased from 65 to 12% of delivered oxygen. Furthermore, the reduction in peak respiratory rate became evident at lower energy demands of the contraction sequence. Myxothiazol inhibition of respiration was not dependent on the presence of muscle contractions but was evident when mitochondria were uncoupled with carbonyl cyanide m-chlorophenylhydrazone. A 50% effective dosage (ED50) of 0.21 microM myxothiazol for inhibition of peak oxygen consumption closely resembled the inhibition of NADH-cytochrome c reductase activity (ED50 of 0.27 microM) determined from homogenates of the same muscles. This suggests that the peak oxygen consumption of skeletal muscle is tightly coupled to the capacity for electron transport evaluated by flux through NADH-cytochrome c reductase. If the enzyme activity measured in vitro correctly represents available enzymatic capacity within contracting muscle, approximately 75% of electron transport capacity for handling reducing equivalents generated from NADH is utilized during peak oxygen consumption of rat hindlimb muscle contracting in situ.

scholarly journals Overexpression of Ubiquinol-Cytochrome c Reductase Core Protein 1 May Protect H9c2 Cardiac Cells by Binding with Zinc

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Tingting Yi ◽  
Xiaoxiao Wu ◽  
Zonghong Long ◽  
Guangyou Duan ◽  
Zhuoxi Wu ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Caspase 3 ◽  
Direct Evidence ◽  
Core Protein ◽  
Ischemia Reperfusion ◽  
Cardiac Cells ◽  
Protective Effects ◽  
Cytochrome C Reductase ◽  
Simulated Ischemia

In several recent studies, proteomics analyses suggest that increase of ubiquinol-cytochrome c reductase core protein 1 (UQCRC1) is cardio-protective. However, direct evidence for this effect has not yet been obtained. Thus, the current study aimed to determine this effect and the mechanism underlying this effect. The results showed that overexpression of UQCRC1 protected H9c2 cardiac cells against in vitro simulated ischemia-reperfusion by maintaining mitochondrial membrane potential and suppressing the expression of caspase-3. These protective effects were significantly enhanced by exogenous Zn2+ but completely abolished by Zn2+-selective chelator TPEN. Furthermore, the upregulation of UQCRC1 reduced the concentration of free Zn2+ in mitochondria, whereas the downregulation of UQCRC1 increased the concentration of free Zn2+ in mitochondria. In conclusion, the overexpression of UQCRC1 can protect H9c2 cardiac cells against simulated ischemia/reperfusion, and this cardio-protective effect is likely mediated by zinc binding.

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