Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.99.3 (acyl-CoA dehydrogenase)
 1,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities (Vmax) of hexokinase, glycogen phosphorylase, glucose-6-phosphate dehydrogenase, phosphofructokinase, lactate dehydrogenase, citrate synthase, cytochrome c oxidase, and 3-OH-acyl-CoA dehydrogenase in human skeletal muscles were compared with the in vitro utilization of glucose and palmitic acid assessed under optimal conditions. Statistically significant correlations between substrate fluxes and enzyme activities were found suggesting that the substrate incorporation rate in vitro in some way reflects the capacity of metabolic pathways. The incorporation rate of leucine into muscle proteins was also statistically significantly correlated to the RNA concentration in the muscle tissue. Glycolytic and glycogenolytic enzymes correlated significantly to each other and correlations were also found between aerobic enzymes supporting the validity of constant proportions between certain key enzymes in human skeletal muscles.
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PMID:Incorporation rate of glucose carbon, palmitate carbon and leucine carbon into metabolites in relation to enzyme activities and RNA levels in human skeletal muscles. 17 28

Muscle biopsies were taken from the middle gluteal muscle in 163 healthy Thoroughbreds aged one to six years. The horses were separated according to sex and divided into four different age groups (one, two, three and four to six years). Muscle biopsies were analysed for fibre type (I, IIA and IIB), and the enzyme activities of citrate synthase, 3-OH-acyl-CoA dehydrogenase, lactate dehydrogenase and hexokinase were measured. The percentage of Type I fibres of all horses increased with age, irrespective of sex (from 9 to 16 per cent). The percentage of Type IIA fibres varied with age and sex, increasing in stallions from 34 to 53 per cent and in mares from 27 to 45 per cent, respectively. Correspondingly, the proportion of Type IIB fibres decreased with age and differed between sexes (stallions from 56 to 29 per cent and mares from 65 to 40 per cent) Muscle oxidative capacity increased with age as indicated by significant increases in the activities of citrate synthase (from 32 to 67 mmol/kg/min) and 3-OH-acyl-CoA dehydrogenase (from 20 to 34 mmol/kg/min). The activity of hexokinase increased with age (from 2.4 to 4.8 mmol/kg/min), whereas the activity of lactate dehydrogenase decreased (from 1,754 to 1,444 mmol/kg/min). No differences were seen between stallions and mares in enzyme activities. This study shows that age is one factor influencing enzyme activities, the percentage of Type I fibres and the Type IIA/IIB ratio in M. gluteus medius of Thoroughbreds, and that stallions have a higher Type IIA/IIB ratio compared with mares.
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PMID:Muscle characteristics in Thoroughbreds of different ages and sexes. 188 91

Tibialis anterior (TA) muscles of four small mammals were subjected to chronic nerve stimulation for 28 days (10 Hz, 10 hours per day). Total cellular activities of phosphofructokinase (PFK), hexokinase (HK), citrate synthase (CS), 3-hydroxy-acyl-CoA dehydrogenase (HADH) and 3-hydroxybutyrate dehydrogenase (HBDH) were measured in the stimulated and unstimulated contralateral muscles. Normal TA muscles displayed ranges of oxidative and glycolytic capacities with rabbit TA showing the lowest and mouse TA the highest oxidative capacity. Chronic stimulation was almost without effect in mouse TA. In all other species, glycolytic capacity was decreased and reference enzymes of aerobic-oxidative pathways were increased. Rabbit TA displayed the highest increment in oxidative capacity with approximately three-fold increases in CS and HADH and eleven-fold increases in HBDH. Different responses were also observed for HK. In some cases, the extent of adaptation appeared to be independent of the initial enzyme activity levels, while in other cases it appeared to follow an order which corresponded to the size of the animals. Thus, there exist species-specific ranges of adaptation and adaptive alterations in one species may not necessarily reflect the adaptive response of another species.
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PMID:Specific effects of low-frequency stimulation upon energy metabolism in tibialis anterior muscles of mouse, rat, guinea pig and rabbit. 297 3

In 12 patients with paramyotonia congenita, percutaneous needle biopsies from the brachial biceps muscle were performed. Muscle fibre area, distribution of muscle fibre types I, II-A and II-B and capillarization were not different from healthy controls. Signs of myopathy with central nuclei in the muscle cells were noted in 9 of the patients. 4 of these patients also had small areas with degeneration and, in one, vacuoles were observed. Quantitative determination of muscle glycogen, water and protein content were within normal range as were enzyme activities for hexokinase, lactate dehydrogenase, citrate synthetase and 3-hydroxy-acyl-CoA dehydrogenase.
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PMID:Skeletal muscle in paramyotonia congenita: biochemistry, histochemistry and morphology. 397 54

The effect of altering the percent of dietary carbohydrate on the rate of skeletal muscle glucose uptake was studied using the perfused rat hindlimb preparation. The rats received either a high carbohydrate (HC; 65%), mixed (M; 35%) or low carbohydrate (LC; 10%) isocaloric diet for 7 days. With 0.1 mU/ml of insulin in the perfusate, the muscle of rats on the HC diet had a 33% increase in the rate of glucose uptake and the muscle of rats fed the LC diet a 23% decrease in the rate of glucose uptake when compared to the muscle of rats fed the M diet (3.34 mumol/g/30 min). With 10.0 mU/ml of insulin in the perfusate, ie maximal insulin stimulation, the rate of glucose uptake showed a similar dietary effect as that obtained with 0.1 mU/ml insulin. Compared to the M diet (8.67 mumol/g/30 min), the rate of glucose uptake increased 26% in muscle of rats from the HC group and decreased by 20% in muscle of rats from the LC group. Diet had no effect on the rate of muscle glucose uptake in the absence of insulin. Under both maximal and submaximal insulin stimulation, glycogen accumulation was greatest in muscle from HC fed rats and least in muscle from LC fed rats. During perfusion muscle intracellular free glucose and glucose-6-phosphate accumulation for the three dietary groups was negligible. The groups did not differ significantly in their muscle hexokinase or beta-hydroxyl acyl CoA dehydrogenase activities.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of dietary carbohydrate on skeletal muscle glucose uptake. 397 51

The present study attempts to assess whether the marked seasonal changes in the capacity for shivering thermogenesis in American goldfinches (Carduelis tristis) involve adjustments of metabolic pathways of the pectoralis muscles similar to those observed in mammalian muscle in response to endurance training, i.e., changes favoring increased reliance on fatty acid oxidation and decreased utilization of carbohydrate reserves. Analysis of seasonal changes in enzyme profile of the pectoralis muscle revealed that winter-acclimatized birds have significantly greater (P less than 0.05) activities of phosphorylase, phosphofructokinase, and beta-hydroxy-acyl-CoA dehydrogenase than do birds in other seasons. The activities of citrate synthase and hexokinase do not vary seasonally. These results differ fundamentally from the pattern of changes in enzyme activities associated with endurance adaptation in mammals. Furthermore no seasonal changes were observed in capacities for the oxidation of fatty acids (palmitate and linoleate) or pyruvate in either crude homogenates or isolated mitochondria of goldfinch pectoralis muscles. The oxidation of pyruvate by isolated pectoralis muscle mitochondria was inhibited (greater than 90%) by the oxidation of palmitoyl carnitine at palmitoyl carnitine concentrations as low as 50 microM. These data agree with physiological observations indicating little use of glucose by this tissue during steady-state shivering. However, the extent of this inhibition does not vary seasonally. Therefore the present study fails to document any significant seasonal change in the catabolic pathways of the pectoralis muscle that would link observed seasonal changes in capacity for shivering thermogenesis with a shift in the balance of substrate use by this tissue.
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PMID:Seasonal acclimatization in American goldfinches: the role of the pectoralis muscle. 622 30

Linoleate monohydroperoxide (L-HPO), methyl linoleate monohydroperoxide (ML-HPO), and methyl hydroperoxy-epoxy-octadecenoate (ML-X) inhibited state 3 respiration of mitochondria when palmitate, palmitoyl CoA, or L-palmitoylcarnitine was used as a substrate. L-HPO was the most effective, and 50% inhibition of palmitate-supported respiration was observed with 2, 3.3, and 6.5 nmol/mg protein of L-HPO, ML-X, and ML-HPO, respectively. Almost the same values were obtained when palmitoyl CoA or L-palmitoylcarnitine was used in place of palmitate. L-HPO inhibited the reaction of beta-oxidation in mitochondria in a similar concentration range (4 nmol/mg protein for 50% inhibition) when L-palmitoylcarnitine was used as a substrate. L-HPO also inhibited the formation of 3-hydroxypalmitoylcarnitine from the same substrate. Carnitine palmitoyltransferase activity of mitochondria was inhibited by L-HPO, 50% inhibition occurring at 12 nmol/mg protein. These inhibitory effects of L-HPO were weaker when ATP was removed by hexokinase and glucose. ATP-dependent formation of carnitine ester of L-HPO was also suggested. It was deduced that L-HPO (and ML-X and ML-HPO after hydrolysis) was converted to carnitine ester and inhibited the palmitate metabolism at the site(s) of intramitochondrial carnitine palmitoyltransferase (and possibly acyl CoA dehydrogenase).
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PMID:Inhibition of palmitate oxidation in mitochondria by lipid hydroperoxides. 672 34

The middle gluteal muscle of five, two-year-old untrained trotters was investigated by repeated needle biopsy sampling over a training period of six months. A second group of five, three-year-old untrained horses was included to examine the effect of growth. After the training period increases were found in the relative distribution of slow twitch (ST) fibres from 18 per cent to 25 per cent and fast twitch (FTa) fibres from 36 per cent to 45 per cent, and a decrease in FTb fibres from 46 per cent to 30 per cent. A proportionally equal reduction (approximately 18 per cent) in the cross sectional area of all fibre types was observed after the first two months of training succeeded by an increase to approximately pretraining levels at the end of the period. The number of capillaries per fibre was enhanced from 1.7 to 2.4. Proliferation of capillaries occurred around fibres of all types. The metabolic adaptations showed increases in the activities of 3-hydroxy-acyl-CoA dehydrogenase (HAD) (50 per cent) and citrate synthase (31 per cent). Growth had no effect on the relative fibre type distribution nor the capillary per fibre ratio, but as the mean fibre area increased 36 per cent (primarily because of increases in FT fibres) the number of capillaries/mm2 was lower in the older untrained horses (350 capillaries/mm2) compared with the younger untrained ones (460 capillaries/mm2). Increase with growth was found in the activity of phosphorylase and HAD and a decrease was seen in the activity of hexokinase. It is concluded that the training programme exclusively induced alterations which improved the aerobic capacity of the muscle.
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PMID:Training and growth induced changes in the middle gluteal muscle of young Standardbred trotters. 687 46

The effect of different levels of activity on fiber types, capillaries and enzymes of gastrocnemius and soleus muscles was studied in two groups of cats. The first group was successfully kept in a large room, exercised on a treadmill 15 min daily 5 days per week and kept in individual small cages. Each period lasted 6 weeks. A muscle biopsy was taken after each period. The second group was formed by cats that were caged for over 20 months. In the group caged for over 20 months, gastrocnemius muscle showed higher IIB and lower I fiber type proportion. Fiber cross-sectional area was not different in any condition. All capillary measurements were significantly lower in gastrocnemius muscle of long-term caged cats, and capillaries per mm2 were lower in soleus muscle of these cats. Exercise increased capillary/fiber in soleus muscle but subsequent caging did not reduced it. In soleus muscle, beta-hydroxy-acyl-CoA dehydrogenase levels decreased after the cage period and hexokinase levels increased after the exercise and decreased after the cage period. In conclusion, different levels of activity for short time produced enzyme changes in soleus muscle, whereas long-term inactivity changed fiber type proportion in gastrocnemius muscle and reduced capillary supply.
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PMID:Inactivity changed fiber type proportion and capillary supply in cat muscle. 917 79

The effect of sprint training and detraining on supramaximal performances was studied in relation to muscle enzyme adaptations in eight students trained four times a week for 9 weeks on a cycle ergometer. The subjects were tested for peak oxygen uptake (VO2peak), maximal aerobic power (MAP) and maximal short-term power output (Wmax) before and after training and after 7 weeks of detraining. During these periods, biopsies were taken from vastus lateralis muscle for the determination of creatine kinase (CK), adenylate kinase (AK), glycogen phosphorylase (PHOS), hexokinase (HK), phosphofructokinase (PFK), lactate dehydrogenase (LDH) and its isozymes, 3-hydroxy-acyl-CoA dehydrogenase (HAD) and citrate synthase (CS) activities. Training induced large improvements in Wmax (28%) with slight increases (3%) in VO2peak (P < 0.10). This was associated with a greater glycolytic potential as shown by higher activities for PHOS (9%), PFK (17%) and LDH (31%) after training, without changes in CK and oxidative markers (CS and HAD). Detraining induced significant decreases in VO2peak (4%), MAP (5%) and oxidative markers (10-16%), while Wmax and the anaerobic potential were maintained at a high level. This suggests a high level in supramaximal power output as a result of a muscle glycogenolytic and glycolytic adaptation. A long interruption in training has negligible effects on short-sprint ability and muscle anaerobic potential. On the other hand, a persistent training stimulus is required to maintain high aerobic capacity and muscle oxidative potential. This may contribute to a rapid return to competitive fitness for sprinters and power athletes.
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PMID:Enzyme adaptations of human skeletal muscle during bicycle short-sprint training and detraining. 942 50


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