Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.1.8 (acyl-CoA dehydrogenase)
 785 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The acyl-CoA dehydrogenases (ACDs) are mitochondrial enzymes that dehydrogenate acyl-coenzyme A esters of different chain lengths. Inherited deficiencies of these dehydrogenases are commonly associated with muscle weakness and lipid storage. Numerous assays including spectrophotometric, fluorometric, chemical, and radiochemical procedures have been used, but there is need for a rapid, reproducible assay for the different acyl-CoA dehydrogenases in small frozen samples of human muscle biopsies. We describe a comparative study of dye-linked spectrophotometric assays of the long, medium, and short chain acyl-CoA dehydrogenases in frozen rat and human muscle samples. An optimal procedure is described confirming the value of glass-glass homogenization and assay of a 600g supernatant. Higher activities for all acyl-CoA dehydrogenases, citrate synthase, and cytochrome c oxidase were obtained in rat in contrast to human. The substrate-linked dye reduction method was found superior to the ferricenium or electron transfer flavoprotein acceptor systems. Application of the phenazine ethosulfate-DCPIP-linked method to medium-chain acyl-CoA dehydrogenase (MCAD) was studied in detail and the effect of immunoprecipitation of MCAD allowed for the determination of substrate specificity and the degree of crossover between long-, medium-, and short-chain ACD activity following immunoprecipitation. Finally, a comparison of the specificity and validity of the assay in a patient with MCAD deficiency was performed.
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PMID:Assay of acyl-CoA dehydrogenase activity in frozen muscle biopsies: application to medium-chain acyl-CoA dehydrogenase deficiency. 834 79

To identify genes expressed at intermediate stages of Bacillus subtilis sporulation, we screened for sigma E-dependent promoters. One promoter that we found drives expression of an operon consisting of at least five open reading frames (ORFs). The predicted products of the first three ORFs are very homologous to enzymes involved in fatty acid metabolism, including acetyl coenzyme A (acetyl-CoA) acetyltransferase (thiolase), 3-hydroxybutyryl-CoA dehydrogenase, and acyl-CoA dehydrogenase, respectively. We showed that the fourth ORF encoded a third isozyme of citrate synthase in B. subtilis. Genetic evidence and primer extension results showed that transcription of this operon is directed by the mother cell compartment-specific sigma factor, sigma E, and so the operon was named mmg (for mother cell metabolic genes). Furthermore, we found that a sequence (mmgO) with homology to a catabolite-responsive element mediates glucose repression of mmg promoter activity during sporulation and that this repression was lost in a ccpA mutant.
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PMID:A sigma E dependent operon subject to catabolite repression during sporulation in Bacillus subtilis. 875 38

This study examined the time course of the effects of a high-fat diet and voluntary running exercise on rat skeletal muscle carnitine acyltransferase (CAT), beta-hydroxy-acyl-CoA dehydrogenase (HAD), and citrate synthase (CS) activities. Sixty male Long-Evans rats were randomly allocated to receive either a standard (12% fat by energy) laboratory chow diet (CHOW) or a high-fat (76% by energy) diet (HFD) and placed in running wheels for up to 6 weeks. Energy intakes and weekly voluntary running distances were similar in the CHOW and HFD rats. In both groups, weekly training distance more than doubled from week 4 to week 6. However, increased training had little influence on soleus (s) CAT(s), HAD(s), and CS(s) activities. CAT(s) and HAD(s) activities were higher in the HFD rats than in the CHOW rats from 2 weeks onward (p < 0.005), and CS(s) activities were not different between groups and remained constant over time. In contrast, increased training distance after 4 weeks in the CHOW rats resulted in an increase in deep vastus (v) CAT(v) activities to values similar to those in HFD rats prior to increases in training volume (p < 0.005) but had no effect on their HAD(v) and CS(v) activities. Increases in HAD(v) and CS(v) activities with increased training volume were only seen in the HFD rats (p < 0.005). HAD(v) activities and HAD/CS(v) activity ratios correlated with training distance in the HFD rats only (p < 0.001 and p < 0.01, respectively). These results suggest that a high-fat diet improves the beta-oxidation capacity of rat predominantly slow-twitch soleus muscle and enhances the effects of modest levels of training on the mitochondrial density and beta-oxidation capacity of rat deep vastus mixed fast- and slow-twitch muscles.
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PMID:Time course of the effects of a high-fat diet and voluntary exercise on muscle enzyme activity in Long-Evans rats. 914 40

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

To examine the effects of unweighting on the structural and metabolic adaptations of a non-postural muscle, deltoideus muscle biopsies were taken in seven male healthy subjects, before and after a 37 day bedrest. Myofibrillar ATPase histochemistry demonstrated no change in fibre type distributions (I, IIA, IIB), in fibre cross-sectional areas nor in capillary supply. No difference was noted in enzyme activities of oxidative metabolism (citrate synthase, 3-hydroxy-acyl-CoA dehydrogenase), and glycolysis (hexokinase, lactate dehydrogenase). Electron microscopy showed a decrease in the volume density of lipids but no change in mitochondrial volume density and distribution. The results indicate that bedrest induces no major morphological and biochemical changes in deltoideus muscle, contrary to what was previously reported in vastus lateralis muscle. This lack of changes is probably related to an unaltered deltoideus muscle use.
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PMID:Effects of bedrest on deltoideus muscle morphology and enzymes. 955 Feb 25

The objectives of this study were to determine the effects of 10 consecutive days of moderate-intensity training on 1) the muscular metabolic response to exercise at 100% of the pre-training maximum rate of oxygen consumption (VO2max); and 2) mitochondrial enzyme markers (citrate synthase, CS; succinate dehydrogenase, SDH; 3-hydroxy-acyl-CoA dehydrogenase, HAD) of oxidative capacity in middle gluteal muscle. Six mature, unfit Thoroughbred horses completed both incremental (for determination of VO2max) and high-intensity exercise protocols before (HI1) and after (HI2) training. Training consisted of 10 consecutive days of running at 55% VO2max for 60 min per day (13-14 km/day). For the HI, horses completed a 10 min warm-up, followed by exercise at 100% of pre-training VO2max (mean speed 9.8 m/s) until fatigue. Training resulted in an 8.9% increases in VO2max (Pre: 142 +/- 4 ml/kg bwt/min; Post: 155 +/- 4 ml/kg bwt/min) and a 24% increase in run time to fatigue during HI. Whereas VO2 during HI was not altered by training, peak values for VCO2 and R were significantly lower following training. Compared to HI1, there was a 45% reduction in the net rate of muscle glycogenolysis during HI2. Peak (end exercise) values for plasma and muscle lactate concentrations decreased by 22 and 23%, respectively, after training. Training also attenuated the exercise-associated increase in plasma norepinephrine, but there was no effect on plasma epinephrine concentrations. Maximal activities of CS, SDH, and HAD were unaltered by training. We conclude that 10 days of moderate-intensity exercise results in decreases in muscle glycogenolysis and anaerobic metabolism during high-intensity exercise at the same absolute workload. Furthermore, development of measurable increases in mitochondrial oxidative potential may not be required for expression of these metabolic adaptations in early training.
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PMID:Muscular and metabolic responses to moderate-intensity short-term training. 1065 74

Muscle contraction causes an increase in activity of 5'-AMP-activated protein kinase (AMPK). This study was designed to determine whether chronic chemical activation of AMPK will increase mitochondrial enzymes, GLUT-4, and hexokinase in different types of skeletal muscle of resting rats. In acute studies, rats were subcutaneously injected with either 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR; 1 mg/g body wt) in 0.9% NaCl or with 0.9% NaCl alone and were then anesthetized for collection and freezing of tissues. AMPK activity increased in the superficial, white region of the quadriceps and in soleus muscles but not in the deep, red region of the quadriceps muscle. Acetyl-CoA carboxylase (ACC) activity, a target for AMPK, decreased in all three muscle types in response to AICAR injection but was lowest in the white quadriceps. In rats given daily, 1 mg/g body wt, subcutaneous injections of AICAR for 4 wk, activities of citrate synthase, succinate dehydrogenase, and malate dehydrogenase were increased in white quadriceps and soleus but not in red quadriceps. Cytochrome c and delta-aminolevulinic acid synthase levels were increased in white, but not red, quadriceps. Carnitine palmitoyl-transferase and hydroxy-acyl-CoA dehydrogenase were not significantly increased. Hexokinase was markedly increased in all three muscles, and GLUT-4 was increased in red and white quadriceps. These results suggest that chronic AMPK activation may mediate the effects of muscle contraction on some, but not all, biochemical adaptations of muscle to endurance exercise training.
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PMID:Activation of AMP-activated protein kinase increases mitochondrial enzymes in skeletal muscle. 1084 39

The hypothesis tested was that dietary fat, when compared with an isoenergetic amount of non-structural carbohydrates, stimulates lipolysis in adipose tissue and also stimulates the fatty-acid oxidative capacity in skeletal muscle from horses. Six adult horses were fed a high-fat, glucose or starch containing diet according to a 3 x 3 Latin square design with feeding periods of three weeks. The diets were formulated so that the intake of soybean oil versus either glucose or corn starch were the only variables. In accordance with previous work, whole plasma triacylglycerol (TAG) concentration decreased significantly by 58% following fat supplementation. This fat effect was accompanied by a 247% increase in lipoprotein lipase (LPL) activity in post-heparin plasma. The dietary variables did neither significantly affect the basal in vitro lipolytic rate nor the lipolytic rate after adding noradrenaline. There was no significant diet effect on the activities of hexokinase and phosphofructokinase as indicators of glycolytic flux and citrate synthase and 3-hydroxy-acyl-CoA dehydrogenase as indicators of fatty-acid oxidative capacity. The concentrations of muscle glycogen and TAG were not affected by fat supplementation. It is concluded that our hypothesis is not supported by the present results.
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PMID:Lipid metabolism in equines fed a fat-rich diet. 1088 8

The aim of this study was to evaluate the changes in aerobic and anaerobic metabolism produced by a newly devised short training programme. Five young male volunteers trained daily for 2 weeks on a cycle ergometer. Sessions consisted of 15-s all-out repetitions with 45-s rest periods, plus 30-s all-out repetitions with 12-min rest periods. The number of repetitions was gradually increased up to a maximum of seven. Biopsy samples of the vastus lateralis muscle were taken before and after training. Performance changes were evaluated by two tests, a 30-s all-out test and a maximal progressive test. Significant increases in phosphocreatine (31%) and glycogen (32%) were found at the end of training. In addition, a significant increase was observed in the muscle activity of creatine kinase (44%), phosphofructokinase (106%), lactate dehydrogenase (45%), 3-hydroxy-acyl-CoA dehydrogenase (60%) and citrate synthase (38%). After training, performance of the 30-s all-out test did not increase significantly, while in the maximal progressive test, the maximum oxygen consumption increased from mean (SD) 57.3 (2.6) ml x min(-1) x kg(-1) to 63.8 (3.0) ml min(-1) x kg(-1), and the maximum load from 300 (11) W to 330 (21) W; all changes were significant. In conclusion, this new protocol, which utilises short durations, high loads and long recovery periods, seems to be an effective programme for improving the enzymatic activities of the energetic pathways in a short period of time.
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PMID:A short training programme for the rapid improvement of both aerobic and anaerobic metabolism. 1098 4

The influence of training on GLUT4 expression in slow- and fast-twitch skeletal muscle fibres was studied in male endurance-trained athletes and control subjects. The trained state was ensured by elevated maximal oxygen uptake (29%), as well as citrate synthase (60%) and 3-hydroxy-acyl-CoA dehydrogenase (38%) activities in muscle biopsy samples of the vastus lateralis. GLUT4 densities in slow- and fast-twitch fibres were measured by the use of a newly developed, sensitive method combining immunohistochemistry with morphometry, and no effect of training was found. GLUT4 density was higher in slow-twitch fibres compared to fast-twitch fibres (P<0.05) when biopsy samples from untrained subjects were examined. In athletes GLUT4 density was identical in slow- and fast-twitch fibres. Slow-twitch fibre diameters were 10% larger in the athletes (P<0.01), and slow-twitch fibre fractions were 140% of the fraction in the control group. Thus, GLUT4 originating from slow-twitch fibres was increased by 30% (P<0.02) in athletes. We conclude that long-lasting endurance training increases slow-twitch fibre GLUT4 expression by means of an elevated slow-twitch fibre mass in human skeletal muscle.
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PMID:The GLUT4 density in slow fibres is not increased in athletes. How does training increase the GLUT4 pool originating from slow fibres? 1171 44


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