Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diaphragmatic muscle fiber types were determined in the costal and crural segments of swine diaphragm at 4 postnatal ages (1 day, 1 month, 6 months, and between 3-6 yr of age). Fiber types were differentiated by enzyme histochemistry for adenosine triphosphatase and reduced nicotinamide adenine dinucleotide. A progressive increase in the number of type I fibers occurred in both costal and crural segments from birth to 6 months of age. The number of type IIA fibers decreased and type IIB fibers increased over the same time period. Type IIC fibers were present through 1 month of age, were rarely observed at 6 months, and were not found in older animals. Type I fibers were more numerous in the crural portion of the diaphragm. The cross-sectional area of all fiber types in both costal and crural segments increased significantly with age. No preferential fiber type growth was noted in either segment of the diaphragm. These data suggest that the pig diaphragmatic muscle is differentiated into its adult form by 6 months of postnatal age, but fiber cross-sectional area growth continues along with body growth.
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PMID:Diaphragmatic muscle fiber type development in swine. 296 Sep 46

Using quantitative histochemical techniques, it was determined that the tensor tympani muscle of the cat consists of three muscle fiber types: type 1, type 2A (staining characteristics similar to the type 1 and type 2A muscle fibers found in the control tibialis anterior muscles), and a third unclassified fiber type (type 3) similar to the 2A fiber type except that it had extremely dense alkaline actomyosin adenosine triphosphatase staining (mean transmittance, type 2A = 33.6%; type 3 = 17.3%), as well as dense staining for periodic acid-Schiff, menadione-linked alpha-glycerolphosphate dehydrogenase, nicotinamide-adenine dinucleotide tetrazolium reductase, and succinic dehydrogenase. The type 1 fiber population was smaller in diameter (mean +/- SD, 14 +/- 4 microns) than the type 2A fiber (mean +/- SD, 21 +/- 5 microns) and the type 3 fiber (mean +/- SD, 22 +/- 6 microns) populations. In all muscles, intrafascicular and extrafascicular fat accumulations were found, with the majority being extrafascicular. Calculations indicate that the tendon occupies approximately 41% of the total muscle volume, while the muscle fibers constitute 59% of the volume.
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PMID:Muscle fiber types in the cat middle ear muscles. II. Tensor tympani. 296 26

The purpose of this study was to determine histologically the distribution of microspheres (MSs) (14 micron), and hence the relative distribution of blood flow, in rat plantaris muscle relative to the fiber types (fast-twitch-oxidative-glycolytic [FOG], fast-twitch-glycolytic [FG], and slow-twitch-oxidative [SO]). Three conditions were investigated: 1) preexercise standing; 2) treadmill locomotion at 15 m/min (fast walking); and 3) treadmill locomotion at 60 m/min (moderate galloping). The MS suspension (containing 1 x 10(6) MSs) was infused into the ascending aorta via a catheter in the carotid artery under each of the 3 conditions so that MSs were distributed to the tissues in proportion to their respective blood flows. Sections (20 micron) of the plantaris muscle were cut and assayed for reduced nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR) and myofibrillar adenosine triphosphatase (ATPase) activities so the fibers could be typed as SO, FOG, or FG. MSs were located in the NADH-TR sections, and the fibers next to the MSs were classified and counted. The observed numbers of fibers of each type in each condition that were adjacent to MSs were compared to the predicted number of adjacent fibers based on the assumption the MSs were randomly distributed in the tissue. This analysis demonstrated that MSs (and blood flows) were preferentially distributed to SO fibers during preexercise, to SO and FOG fibers during slow locomotion, and to FOG fibers during fast locomotion. The data support the contention that blood flow is distributed in muscles of conscious animals as functions of fiber type and exercise intensity.
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PMID:Distribution of microspheres in plantaris muscles of resting and exercising rats as a function of fiber type. 297 25

Activity of transport ATPases was studied in erythrocyte membranes and synaptosomal fraction of cervical department of spinal cord obtained from rats in dynamics of botulinic C intoxication Na+, K+-ATPase was inhibited by the competitive type in the synaptosomal brain fraction at the preclinical period of intoxication and by the noncompetitive type at the step of skeletal muscle paresis. In erythrocyte membranes activity of Na+, K+-ATPase was inhibited by the mixed type at the preclinical period of intoxication and the enzymatic activity was inhibited by the noncompetitive type at the step of skeletal muscle paresis. The Na+, K+-ATPase from biological membranes was reactivated by unithiol and nicotinamide in dynamics of intoxication. The toxin was shown to activate Mg2+-ATPase in brain synaptosomal fraction.
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PMID:[Effect of botulinum toxin on the activity of transport ATPases in biological membranes]. 298 43

Comparisons were made of the histochemical characteristics of skeletal muscle from 10 animal species. The basic comparison was made from the staining patterns for the myofibrillar actomyosin ATPase produced by preincubation of fresh frozen cross-sections of muscle at alkaline pH (10.30) or acid pH (4.60) with those produced by preincubation in media containing Cu2+ at alkaline pH (10.30), near neutral pH (7.40), or acid pH (4.60). Muscle sections were also stained for reduced nicotinamide adenine dinucleotide tetrazolium reductase and alpha-glycerophosphate dehydrogenase to provide an indication of the relative oxidative and glycolytic capacity of the different fiber types. Type II fibers in mixed fibered muscles were either very sensitive, moderately sensitive, or relatively insensitive to inactivation of the myofibrillar actomyosin ATPase after acid preincubation. These fibers were identified as type IIA1, IIA2, and IIA3, respectively. The myofibrillar actomyosin ATPase of the type I fibers of these muscles, with the exception of those in mouse muscle, was activated by pretreatment with acid. A separation of animal species was possible based on the stability of the IIA1 fibers to inclusion of Cu2+ in the preincubation medium. For one group of animals (rat, mouse, monkey, man, dog, rabbit, and cow), a reciprocal relationship existed between lability to acid and stability to Cu2+ for type IIA1 and IIA3 fibers, respectively. For the second group of animals (horse, ass, and cat) there was a parallel relationship between lability or stability of the type IIA1 and IIA3 fibers to pretreatment with either acid or Cu2+.
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PMID:Comparison of fiber types in skeletal muscles from ten animal species based on sensitivity of the myofibrillar actomyosin ATPase to acid or copper. 315 28

The purpose of this study was to determine whether 8-12 wk of endurance training produces biochemical and histochemical adaptations in skeletal muscle in foxhounds. Analyses were performed on samples removed from gastrocnemius, triceps, and semitendinosus muscles of foxhounds before and after a treadmill running program. Biochemical analysis showed that training did not alter the activities of phosphofructokinase, beta-hydroxyacyl-CoA dehydrogenase, succinate dehydrogenase, or total phosphorylase. Histochemical analysis of myofibrillar actomyosin ATPase demonstrated three distinct classes of type II fibers and one type I fiber in the semitendinosus and triceps muscles and two type II and two type I fibers in the gastrocnemius muscle. Fiber type distribution and oxidative and glycolytic potentials, as indicated by nicotinamide adenine dinucleotide tetrazolium reductase or alpha-glycerophosphate dehydrogenase staining intensity, were unaltered by training. Similarly, capillary density, capillary-to-fiber ratios, and capillary area-to-fiber area ratios did not change with training. Thus, unlike humans and other mammals (i.e., rat), these foxhounds did not manifest biochemical or histochemical adaptations in skeletal muscle as the result of endurance training. This is consistent with the results of the study in which endurance training produced a 27% increase in maximal cardiac output and a 4% increase in maximal arteriovenous O2 extraction in foxhounds.
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PMID:Dynamic exercise training in foxhounds. II. Analysis of skeletal muscle. 316 58

The rate of hydrolysis of adenosine triphosphate (ATP) by chemically skinned rabbit muscle fibres was measured as a function of Mg ATP concentration in the range 5 microM to 5 mM. Pyruvate kinase and lactate dehydrogenase were used to link adenosine diphosphate formation to oxidation of nicotinamide adenine dinucleotide which was followed by the change in absorption at 340 nm. The ATPase rate of a fully activated fibre (pCa = 4.5) increased monotonically with Mg ATP concentration in a manner that could be readily fitted by a hyperbola. At 15 degrees C, pH 7 and an ionic strength of 0.2 M the rate at saturating Mg ATP (Vm) was 1.78 +/- 0.2 s-1 per myosin head (mean +/- S.D.; n = 6) and the Mg ATP concentration needed for half the maximal rate (Km) was 16.6 +/- 2 microM. The ATPase of fibres that had been stabilized by cross-linking with 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide (EDC) was also investigated. Cross-linking did not significantly affect the Vm or Km and these fibres proved useful for investigating the adequacy of the pyruvate kinase activity for regenerating hydrolysed ATP. Myofibrils were cross-linked with EDC or glutaraldehyde to prevent shortening. Their ATPase properties were investigated: the values of Vm were 0.85 +/- 0.18 (mean +/- S.D.; n = 14) and 0.82 +/- 0.05 s-1 (n = 6) and of Km were 18.0 +/- 2.8 and 12.4 +/- 2.4 microM respectively. The values of Vm and Km for EDC cross-linked myofibrils were fairly insensitive to ionic strength, the Km decreasing 40% and the Vm increasing 50% for a change from 0.2 to 0.3 M. This slight dependence on ionic strength is considered in relation to the ionic strength dependence of the elementary rate constants of the actomyosin subfragment-1 ATPase cycle.
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PMID:Dependence of adenosine triphosphatase activity of rabbit psoas muscle fibres and myofibrils on substrate concentration. 316 18

Inhibition of ADP phosphorylation by both glycolysis and mitochondria in P388D1 cells exposed to H2O2 is described. Net glucose uptake and lactate production were inhibited by oxidant exposure (ED50 = 50-100 microM). Glycolysis was specifically inactivated at the glyceraldehyde-3-phosphate dehydrogenase step by three independent mechanisms: (a) direct inactivation of the intracellular enzyme (ED50 approximately equal to 100 microM); (b) reduction of the intracellular concentration and redox potential of its nicotinamide cofactors; and (c) a cytosolic pH shift further from the enzyme optima. Consistent with inhibition of glycolysis at the glyceraldehyde-3-phosphate dehydrogenase step, a rise in the intracellular concentration of glyceraldehyde 3-phosphate, dihydroxyacetone phosphate, and fructose 1,6-bisphosphate was observed. The calculated combined inhibition of glyceraldehyde-3-phosphate dehydrogenase activity could be reasonably correlated with the depression in glycolytic flux rate with the appropriate modeling. The steady-state contribution by mitochondria to the total intracellular ATP pool was indirectly determined by the use of various metabolic inhibitors and was found to rapidly decline following exposure to 300-800 microM H2O2. The inhibition of ADP phosphorylation appeared to be related more to the direct inhibition of the ATPase-synthase complex rather than to the diminished capacity of the respiratory chain for coupled electron transport. Both the estimated rates of ADP phosphorylation by glycolysis and mitochondria and the estimated rate of ATP hydrolysis by ongoing metabolism were utilized to model the approximate decline in intracellular ATP expected at 15-min exposure to various H2O2 concentrations. Theoretical calculations and the measured intracellular ATP status were in good agreement. Oxidant exposure for 15 min resulted in dose-dependent killing of the cells (ED50 = 500 microM), indicating a close correlation between H2O2-mediated loss of intracellular ATP and cell viability. The possible contribution of impaired energy homeostasis during oxidant-mediated injury to the process of cell dysfunction and death is discussed.
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PMID:Mechanisms of oxidant-mediated cell injury. The glycolytic and mitochondrial pathways of ADP phosphorylation are major intracellular targets inactivated by hydrogen peroxide. 333 86

The interaction between pure transhydrogenase and ATPase (Complex V) from beef heart mitochondria was investigated with transhydrogenase-ATPase vesicles in which the two proteins were co-reconstituted by dialysis or dilution procedures. In addition to phosphatidylcholine and phosphatidylethanolamine, reconstitution required phosphatidylserine and lysophosphatidylcholine. Transhydrogenase-ATPase vesicles catalyzed a 20-30-fold stimulation of the reduction of NADP+ or thio-NADP+ by NADH and a 70-fold shift of the apparent equilibrium expressed as the nicotinamide nucleotide ratio [NADPH][NAD+]/[NADP+][NADH]. In both of these respects, the transhydrogenase-ATPase vesicles were severalfold more efficient than beef heart submitochondrial particles. By measuring the ATP-driven transhydrogenase and the oligomycin-sensitive ATPase activities simultaneously and under the same conditions at low ATP concentrations, i.e. below 15 microM, the ATP-driven transhydrogenase/oligomycin-sensitive ATPase activity ratio was found to be about 3. This value is consistent with the stoichiometries of three protons translocated per ATP hydrolyzed and one proton translocated per NADPH formed and with a mechanism where the two enzymes interact through a delocalized proton-motive force.
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PMID:Energy-linked nicotinamide-nucleotide transhydrogenase. Characterization of reconstituted ATP-driven transhydrogenase from beef heart mitochondria. 355 83

Muscle biopsy samples were collected from the middle gluteal muscle of seven horses undergoing a nine-month endurance training programme. Samples were collected before the programme began and again after three, six and nine months of training. A fifth sample was collected three months after training ceased. Serial muscle sections were reacted histochemically for myosin adenosine triphosphatase after either acid (pH 4.3 and 4.6) or alkaline (pH 10.3) pre-incubation, and muscle fibres identified as type I, IIA, IIB or IIC. The oxidative capacity of individual fibres was assessed, using the reduced nicotinamide dinucleotide tetrazolium reductase stain, and the number of intermyofibrillar capillaries adjacent to each fibre was counted after staining, using the alpha-amylase periodic acid Schiff technique. Biochemical analyses involved the fluorometric measurement of the enzymes citrate synthase, 3-hydroxy acyl CoA dehydrogenase and lactate dehydrogenase as markers of end terminal oxidative, beta oxidative and glycolytic potential, respectively. There was an increase in the percentage of type IIB fibres having high nicotinamide dinucleotide tetrazolium reductase staining after three months training. This increase persisted throughout the period of training and during the period without training. There was an increase in the number of capillaries adjacent to type IIB fibres after six and nine months training. These had returned to near pre-training numbers after three months without training. There were increases in the activities of citrate synthase and 3-hydroxy acyl CoA dehydrogenase after three months training. The activities of both enzymes continued to rise throughout training and the highest activities were attained after nine months.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of a nine-month endurance training programme on muscle composition in the horse. 367 37


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