Maximal enzyme activities of energy production pathways in the heart, hepatopancreas, and white muscle of the giant scallop (Placopecten magellanicus) and lobster (Homarus americanus)

1992 ◽  
Vol 70 (4) ◽  
pp. 720-724 ◽  
Author(s):  
John M. Stewart ◽  
Molly E. Brass ◽  
Robert C. Carlin ◽  
Heather Black
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
White Muscle ◽  
Citrate Synthase ◽  
Ketone Bodies ◽  
Homarus Americanus ◽  
Carnitine Palmitoyltransferase ◽  
Placopecten Magellanicus ◽  
Flexor Muscle ◽  
Low Levels

The maximal activities of enzymes in energy pathways were measured in the ventricle, hepatopancreas, and white muscle of lobster (Homarus americanus; abdominal flexor) and giant scallop (Placopecten magellanicus; phasic adductor). Both animals show an energy metabolism based upon the utilization of carbohydrate. Carnitine palmitoyltransferase activity was not detected, and this was interpreted as an incapacity for mitochondrial β-oxidation of fatty acids; the absence of 3-hydroxybutyrate dehydrogenase and D-3-hydroxybutyrate indicated that ketone bodies were not a significant energy source. The levels of hexokinase, phosphofructokinase I, citrate synthase, and cytochrome c oxidase in the myocardia of both animals suggest a dependence on the aerobic processing of both blood-borne and glycogen-derived glucose. The significance of the enzyme activity data in the hepatopancreas of both animals was not immediately apparent. The abdominal flexor muscle of the lobster and the phasic adductor of the scallop showed enzyme profiles that suggest a reliance on glycolysis to fuel rapid bursts of activity. In the lobster flexor the presence of hexokinase and phosphofructokinase I along with low levels of citrate synthase and cytochrome c oxidase indicated that this tissue can utilize blood-borne and glycogenic glucose anaerobically. The absence of hexokinase, the low levels of citrate synthase and cytochrome c oxidase, and the presence of phosphofructokinase I in the scallop adductor suggested a reliance upon glycogen-fueled glycolysis to power burst activity. 3-Hydroxyacyl-CoA dehydrogenase was found in all tissues except the lobster flexor, which was curious in light of the undetectable activity of carnitine palmitoyltransferase.

scholarly journals Oxidative properties of carp red and white muscle

1989 ◽  
Vol 143 (1) ◽  
pp. 321-331 ◽  
Author(s):  
C. D. Moyes ◽  
L. T. Buck ◽  
P. W. Hochachka ◽  
R. K. Suarez
Keyword(s):  
Amino Acids ◽  
White Muscle ◽  
Citrate Synthase ◽  
Ketone Bodies ◽  
Redox Balance ◽  
Fatty Acyl ◽  
Oxidation Rates ◽  
Substrate Preferences ◽  
Glycerophosphate Dehydrogenase ◽  
Wide Range

Substrate preferences of isolated mitochondria and maximal enzyme activities were used to assess the oxidative capacities of red muscle (RM) and white muscle (WM) of carp (Cyprinus carpio). A 14-fold higher activity of citrate synthase (CS) in RM reflects the higher mitochondrial density in this tissue. RM mitochondria oxidize pyruvate and fatty acyl carnitines (8:O, 12:O, 16:O) at similarly high rates. WM mitochondria oxidize these fatty acyl carnitines at 35–70% the rate of pyruvate, depending on chain length. WM has only half the carnitine palmitoyl transferase/CS ratio of RM, but similar ratios of beta-hydroxyacyl CoA dehydrogenase/CS. Ketone bodies are poor substrates for mitochondria from both tissues. In both tissues mitochondrial alpha-glycerophosphate oxidation was minimal, and alpha-glycerophosphate dehydrogenase was present at low activities, suggesting the alpha-glycerophosphate shuttle is of minor significance in maintaining cytosolic redox balance in either tissue. The mitochondrial oxidation rates of other substrates relative to pyruvate are as follows: alpha-ketoglutarate 90% (RM and WM); glutamate 45% (WM) and 70% (RM); proline 20% (WM) and 45% (RM). Oxidation of neutral amino acids (serine, glycine, alanine, beta-alanine) was not consistently detectable. These data suggest that RM and WM differ in mitochondrial properties as well as mitochondrial abundance. Whereas RM mitochondria appear to be able to utilize a wide range of metabolic fuels (fatty acids, pyruvate, amino acids but not ketone bodies), WM mitochondria appear to be specialized to use pyruvate.

scholarly journals Chlorpromazine and carnitine-dependency of rat liver peroxisomal β-oxidation of long-chain fatty acids

1987 ◽  
Vol 241 (3) ◽  
pp. 783-791 ◽  
Author(s):  
J Vamecq
Keyword(s):  
Fatty Acids ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Rat Liver ◽  
Fatty Acyl ◽  
Carnitine Palmitoyltransferase ◽  
Acid Oxidation ◽  
Synthetase Activity ◽  
Mitochondrial Fatty Acid Oxidation ◽  
Mitochondrial Fatty Acid

The enzyme targets for chlorpromazine inhibition of rat liver peroxisomal and mitochondrial oxidations of fatty acids were studied. Effects of chlorpromazine on total fatty acyl-CoA synthetase activity, on both the first and the third steps of peroxisomal beta-oxidation, on the entry of fatty acyl-CoA esters into the peroxisome and on catalase activity, which allows breakdown of the H2O2 generated during the acyl-CoA oxidase step, were analysed. On all these metabolic processes, chlorpromazine was found to have no inhibitory action. Conversely, peroxisomal carnitine octanoyltransferase activity was depressed by 0.2-1 mM-chlorpromazine, which also inhibits mitochondrial carnitine palmitoyltransferase activity in all conditions in which these enzyme reactions are assayed. Different patterns of inhibition by the drug were, however, demonstrated for both these enzyme activities. Inhibitory effects of chlorpromazine on mitochondrial cytochrome c oxidase activity were also described. Inhibitions of both cytochrome c oxidase and carnitine palmitoyltransferase are proposed to explain the decreased mitochondrial fatty acid oxidation with 0.4-1.0 mM-chlorpromazine reported by Leighton, Persico & Necochea [(1984) Biochem. Biophys. Res. Commun. 120, 505-511], whereas depression by the drug of carnitine octanoyltransferase activity is presented as the factor responsible for the decreased peroxisomal beta-oxidizing activity described by the above workers.

Mitochondrial DNA replication and transcription are dissociated during embryonic cardiac hypertrophy

1991 ◽  
Vol 261 (6) ◽  
pp. C1091-C1098 ◽  
Author(s):  
J. M. Kennedy ◽  
S. R. Lobacz ◽  
S. W. Kelley
Keyword(s):  
Mitochondrial Dna ◽  
Cytochrome C ◽  
Cardiac Hypertrophy ◽  
Cytochrome C Oxidase ◽  
Oxidase Activity ◽  
Citrate Synthase ◽  
Incubation Temperature ◽  
Mitochondrial Gene ◽  
Gene Replication ◽  
Mitochondrial Dna Copy Number

Cardiac hypertrophy was produced in embryonic chicks by decreasing the incubation temperature from 38 degrees C to 32 degrees C on day 11. Increases in ventricular protein, RNA, and DNA support the cardiac enlargement. Cytochrome-c oxidase activity and citrate synthase activity were depressed in hypothermic ventricles by 63% and 56%, respectively. No significant differences were seen in enzyme activities in pectoralis muscles. The involvement of mitochondrial gene replication and transcription was evaluated using a cDNA clone for the mitochondrially encoded subunit III of cytochrome-c oxidase (CO III). Quantitative slot-blot analysis demonstrated that the relative CO III mRNA concentration was reduced in hypothermic ventricles. In contrast, the relative mitochondrial DNA concentration was increased in hypothermic ventricles. Taken together, these data indicate that a hypothermia-induced decrease in cytochrome-c oxidase activity is associated with a decrease in CO III mRNA, which is not coupled to a decrease in the mitochondrial DNA copy number. This dissociation of mitochondrial gene replication and transcription may provide a useful model for examining the regulation of mitochondrial biogenesis.

Mitochondrial Protein Content and in Vivo Synthesis Rates in Skeletal Muscle from Critically Ill Rats

1996 ◽  
Vol 91 (4) ◽  
pp. 475-481 ◽  
Author(s):  
Olav E. Rooyackers ◽  
Alexande R H. Kersten ◽  
Anton J. M. Wagenmakers
Keyword(s):  
Skeletal Muscle ◽  
Critical Illness ◽  
Cytochrome C ◽  
Protein Content ◽  
Cytochrome C Oxidase ◽  
Citrate Synthase ◽  
Mitochondrial Protein ◽  
Substantial Reduction ◽  
Mitochondrial Content

1. Recently we reported decreased activities of two mitochondrial marker enzymes (citrate synthase and cytochrome c oxidase) in skeletal muscle from a rat model of critical illness (zymosan injection). In the present study we investigated (i) whether these decreases in enzyme activity reflect a reduction in mitochondrial content and (ii) whether this potential reduction in mitochondrial content was the result of decreased mitochondrial protein synthesis rates. 2. Mitochondrial protein content was calculated from the activities of cytochrome c oxidase in whole-muscle homogenates and purified mitochondria. Synthesis rates of mitochondrial protein in vivo were studied by measuring the incorporation of [3H]phenylalanine into mitochondrial protein using the flooding dose technique. 3. Mitochondrial protein content was reduced to 54% of that measured in the pair-fed rats and to 71% of that measured in control rats fed ad libitum 2 days after the zymosan treatment The decreased mitochondrial protein content observed 2 days after zymosan challenge was preceded by a reduced rate of synthesis of mitochondrial protein 16 h after treatment. Both changes were of greater magnitude than the general muscle wasting and the decreased rate of synthesis of mixed protein observed in the zymosan-treated rats. 4. We conclude that the acute phase of critical illness in zymosan-treated rats is characterized by a substantial reduction in muscle mitochondria that is at least in part caused by a decreased rate of synthesis of mitochondrial protein. This derangement in mitochondrial protein metabolism may be related to the impaired muscle function observed during and after critical illness.

Mitochondrial respiration at low levels of oxygen and cytochrome c

2002 ◽  
Vol 30 (2) ◽  
pp. 252-258 ◽  
Author(s):  
E. Gnaiger ◽  
A. V. Kuznetsov
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Respiratory Chain ◽  
Isolated Heart ◽  
Hyperbolic Function ◽  
Excess Capacity ◽  
Hypoxic Conditions ◽  
Substrate Limitation ◽  
Oxygen Conditions ◽  
Low Levels

In the intracellular microenvironment of active muscle tissue, high rates of respiration are maintained at near-limiting oxygen concentrations. The respiration of isolated heart mitochondria is a hyperbolic function of oxygen concentration and half-maximal rates were obtained at 0.4 and 0.7 μM O2 with substrates for the respiratory chain (succinate) and cytochrome c oxidase [N, N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD) + ascorbate] respectively at 30 °C and with maximum ADP stimulation (State 3). The respiratory response of cytochrome c-depleted mitoplasts to external cytochrome c was biphasic with TMPD, but showed a monophasic hyperbolic function with succinate. Half-maximal stimulation of respiration was obtained at 0.4 μM cytochrome c, which was nearly identical to the high-affinity K'm for cytochrome c of cytochrome c oxidase supplied with TMPD. The capacity of cytochrome c oxidase in the presence of TMPD was 2-fold higher than the capacity of the respiratory chain with succinate, measured at environmental normoxic levels. This apparent excess capacity, however, is significantly decreased under physiological intracellular oxygen conditions and declines steeply under hypoxic conditions. Similarly, the excess capacity of cytochrome c oxidase declines with progressive cytochrome c depletion. The flux control coefficient of cytochrome c oxidase, therefore, increases as a function of substrate limitation of oxygen and cytochrome c, which suggests a direct functional role for the apparent excess capacity of cytochrome c oxidase in hypoxia and under conditions of intracellular accumulation of cytochrome c after its release from mitochondria.

Activity-induced adaptations in skeletal muscles of iron-deficient rabbits

1988 ◽  
Vol 65 (2) ◽  
pp. 782-787 ◽  
Author(s):  
W. R. Harlan ◽  
R. S. Williams
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Skeletal Muscles ◽  
Citrate Synthase ◽  
Contractile Activity ◽  
Motor Nerve ◽  
Anterior Compartment ◽  
Iron Deficient ◽  
Electrical Pacing ◽  
Aldolase A

The purpose of this study was to determine whether severe iron deficiency alters the adaptive response of skeletal muscle fibers to a sustained increase in tonic contractile activity. Seven weanling rabbits consumed a low iron diet and underwent phlebotomy twice weekly for 6 mo, resulting in severe anemia (mean Hb 5.5 g/dl). Compared with control animals, tibialis anterior skeletal muscles of iron-deficient animals exhibited reduced concentrations of cytochrome c (4.4 +/- 0.7 vs. 8.6 +/- 0.7 nmol/g tissue; P less than 0.01), and reduced activities of citrate synthase (83 +/- 10 vs. 133 +/- 13 mU/mg protein; P less than 0.01) and cytochrome-c oxidase (2.2 +/- 0.2 vs. 3.6 +/- 0.5 U/mg protein; P less than 0.05). In these muscles mitochondria were swollen and displayed deformed cristae. Less severe biochemical abnormalities were observed in cardiac and soleus skeletal muscles. Ten days of continuous electrical stimulation of the motor nerve supplying anterior compartment muscles of iron-deficient rabbits increased expression of mitochondrial proteins: cytochrome c was increased to 154% of control levels (P less than 0.05), and cytochrome-c oxidase and citrate synthase activities were increased to 199 and 272% of control levels, respectively (P less than 0.005). In addition, electrical pacing increased the fractional volume of mitochondria observed by electron microscopy and reduced the activity of aldolase A by 28% (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of cytochrome c oxidase and citrate synthase in lymphocytes of obese and normal-weight subjects

2002 ◽  
Vol 26 (8) ◽  
pp. 1110-1117 ◽  
Author(s):  
M Čapková ◽  
J Houštěk ◽  
H Hansíková ◽  
V Hainer ◽  
M Kunešová ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Citrate Synthase ◽  
Normal Weight

scholarly journals Cholate Disrupts Regulatory Functions of Cytochrome c Oxidase

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1579
Author(s):  
Rabia Ramzan ◽  
Jörg Napiwotzki ◽  
Petra Weber ◽  
Bernhard Kadenbach ◽  
Sebastian Vogt
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Mitochondrial Respiration ◽  
Sodium Cholate ◽  
Atp Inhibition ◽  
Ros Formation ◽  
Low Levels ◽  
Regulatory Functions ◽  
Relationship Of ◽  
Rate Limiting

Cytochrome c oxidase (CytOx), the oxygen-accepting and rate-limiting enzyme of mitochondrial respiration, binds with 10 molecules of ADP, 7 of which are exchanged by ATP at high ATP/ADP-ratios. These bound ATP and ADP can be exchanged by cholate, which is generally used for the purification of CytOx. Many crystal structures of isolated CytOx were performed with the enzyme isolated from mitochondria using sodium cholate as a detergent. Cholate, however, dimerizes the enzyme isolated in non-ionic detergents and induces a structural change as evident from a spectral change. Consequently, it turns off the “allosteric ATP-inhibition of CytOx”, which is reversibly switched on under relaxed conditions via cAMP-dependent phosphorylation and keeps the membrane potential and ROS formation in mitochondria at low levels. This cholate effect gives an insight into the structural-functional relationship of the enzyme with respect to ATP inhibition and its role in mitochondrial respiration and energy production.

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