Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.25 (triphosphatase)
 1,529 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The histochemical profiles of the bulbospongiosus (BS) and ischiocavernosus (IC) muscles were investigated on autopsy samples obtained from 13 men aged 18 to 33. Adenosine triphosphatase (ATPase) reactions were used for differentiation of muscle fibres into type 1 (slow twitch, tonic), and type 2 (fast twitch, phasic) and subtypes 2A, 2B, 2C. The activity of oxidative and glycolytic enzymes was also assayed. Because the percentage and diameters of both fibre types varied considerably in different areas of the same muscle, two methods of counting were applied and at least two fields of each sample were evaluated. The mean percentage of type 1 fibres in BS muscles was 34.8% and 23.2%, that in IC muscles 49.7% and 39.7%. The mean diameter of type 1 fibres was 31.0 microns (BS) and 26.2 microns (IC), that of type 2 fibres ranged from 30.0 microns (BS) to 36.6 microns (IC). The comparison of BS and IC muscles with other nonskeletal voluntary muscles revealed that BS and IC muscles are similar to the striated sphincters, particularly with regard to the numerical distribution of fibre types and fibre diameters.
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PMID:Histochemical characteristics of bulbospongiosus and ischiocavernosus muscles in man. 768 49

The enhancer-binding protein NIFA is required for transcriptional activation of nif promoters by the alternative holoenzyme form of RNA polymerase, which contains the sigma factor sigma 54 (sigma N). NIFA hydrolyzes nucleoside triphosphates to catalyze the isomerization of closed promoter complexes to transcriptionally competent open complexes. The activity of NIFA is antagonized by the regulatory protein NIFL in response to oxygen and fixed nitrogen in vivo. We have investigated the requirement for nucleotides in the formation and stability of open promoter complexes by NIFA and inhibition of its activity by NIFL at the Klebsiella pneumoniae nifH promoter. Open complexes formed by sigma 54-containing RNA polymerase are considerably more stable to heparin challenge in the presence of GTP than in the presence of ATP. This differential stability is most probably a consequence of GTP being the initiating nucleotide at this promoter. Adenosine nucleosides are specifically required for Azotobacter vinelandii NIFL to inhibit open complex formation by native NIFA, and the nucleoside triphosphatase activity of NIFA is strongly inhibited by NIFL under these conditions. We propose a model in which NIFL modulates the activity of NIFA via an adenosine nucleotide switch.
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PMID:Transcriptional activation of the nitrogenase promoter in vitro: adenosine nucleotides are required for inhibition of NIFA activity by NIFL. 786 90

In order to investigate the activity of certain enzymes [Alkaline phosphatase (ALP), Acid phosphatase (ACP), Adenosine triphosphatase (ATPase), 5'-Nucleotidase (5'-N)] in the proximal epiphysis of the humerus, tissue specimens were obtained from pregnant rats on the 15th, 17th, 19th and 20th days of gestation and on the 1st, 10th, 20th, 30th, 40th and 60th days of postnatal development. Enzymatic activity in the chondral ossification, in the perichondral areas of the epiphysis, was first seen on the 15th day of gestation. ALP and ATPase could also be observed for the first time in fetuses aged 15 days, whereas ACP and 5'-N could not be detected. These latter enzymes were observed for the first time in the proximal humeral epiphysis of fetuses aged 17 days. ALP, a marker for hypertrophic and calcifying cartilage, was observed extensively in the central hypertrophic part of the cartilaginous perichondral zones, which showed calcification during the development of the epiphysis. ALP, ATP and 5'-N activity was very marked in the cytoplasm of osteoblasts and in the periosteal matrix, but strong ACP activity was found in the cells of the chondrolysis zone. In conclusion; according to our observations, heterogeneity of the proximal epiphysis of the humerus exhibits intrinsic differences between the cells of different zones. The activity of all enzymes showed an increase according to the developmental age. This suggests that all of these enzymes play a role during developmental ossification.
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PMID:A histochemical study on the enzymatic activity in the proximal epiphysis of the humerus during the prenatal and postnatal periods in rats. 787 99

The action on left ventricular function of Astragalus Membranaceus (AM), a Qi-tonic, in 20 patients with angina pectoris was studied by means of Doppler Echocardiogram (DEC). It showed that cardiac output increased from 5.09 +/- 0.21 to 5.95 +/- 0.18 L/min 2 weeks after AM was administered (P < 0.01), and no improvement of left ventricular diastolic function appeared. Adenosine triphosphatase activity was not inhibited by using AM, which was different from that of digitalis.
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PMID:[Action of Astragalus membranaceus on left ventricular function of angina pectoris]. 795 Jan 92

Histochemical techniques were employed to study the tissue distribution of hydrolytic enzymes in adult female Onchocerca fasciata (Filarioidea: Onchocercidae). Different tissues differed considerably in the localization and distribution of the six enzymes studied. Acid phosphatase (AcPase) activity was detected in the cuticle, hypodermis and reproductive organs. Alkaline phosphatase (AlkPase) activity was largely absent. Adenosine triphosphatase (ATPase) was found in the somatic musculature and muscles of the uterine ducts, whereas 5'-nucleotidase (5'-Nu) was restricted to young oocytes and dividing embryos in the female worm. Strong glucose-6-phosphatase (G-6-Pase) activity was demonstrated in the uterine epithelial cells and microfilariae, as was weak activity in the hypodermis. Naphthylamidase (NAM) activity was detected in the hypodermis, with lower activity occurring in the somatic musculature. The possible functions of these enzymes are discussed with respect to their location. The hydrolytic enzymes AcPase and NAM in the body wall are probably involved in absorptive-digestive functions, NAM in the somatic musculature may be concerned with tissue protein turnover, and ATPase, 5'-Nu and G-6-Pase may have a role in active transport and energy metabolism.
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PMID:Histochemical distribution of hydrolytic enzymes in adult Onchocerca fasciata (Filarioidea: Onchocercidae). 803 35

This study examined changes in contractile, biochemical, and histochemical properties of slow antigravity skeletal muscle after a 6-day spaceflight mission. Twelve male Sprague-Dawley rats were randomly divided into two groups: flight and ground-based control. Approximately 3 h after the landing, in situ contractile measurements were made on the soleus muscles of the flight animals. The control animals were studied 24 h later. The contractile measurements included force-velocity relationship, force-frequency relationship, and fatigability. Biochemical measurements focused on the myosin heavy chain (MHC) and myosin light chain profiles. Adenosine-triphosphatase histochemistry was performed to identify cross-sectional area of slow and fast muscle fibers and to determine the percent fiber type distribution. The force-velocity relationships of the flight muscles were altered such that maximal isometric tension (Po) was decreased by 24% and maximal shortening velocity was increased by 14% (P < 0.05). The force-frequency relationship of the flight muscles was shifted to the right of the control muscles. At the end of the 2-min fatigue test, the flight muscles generated only 34% of Po, whereas the control muscles generated 64% of Po. The flight muscles exhibited de novo expression of the type IIx MHC isoform as well as a slight decrease in the slow type I and fast type IIa MHC isoforms. Histochemical analyses of flight muscles demonstrated a small increase in the percentage of fast type II fibers and a greater atrophy of the slow type I fibers. The results demonstrate that contractile properties of slow antigravity skeletal muscle are sensitive to the microgravity environment and that changes begin to occur within the 1st wk. These changes were at least, in part, associated with changes in the amount and type of contractile protein expressed.
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PMID:Effect of spaceflight on skeletal muscle: mechanical properties and myosin isoform content of a slow muscle. 804 58

Carbon dioxide laser which is used widely in neurosurgery has less traumatic effect on the tissue beside the lesion than other types of laser. There has been little study on the changes to the vascular tissue, following laser application. We performed a study on 4 groups of dogs; comprising craniectomy only, craniectomy and thyrotropin releasing hormone (TRH), craniectomy and laser, and craniectomy, laser and TRH. We applied CO2 laser on the angular artery of two groups of dogs. To one group we infused TRH for 15 days following the laser application and to the other group we did not. We investigated the ultrastructural and biochemical changes and the effect of TRH on the tissue 15 days following laser application. In our study, we observed an increase in superoxide dismutase activity and a decrease in ATP-ase activities in the degenerated tissue on which CO2 laser was applied. TRH partially prevented the vascular degeneration of CO2 laser but did not significantly change superoxide dismutase and Adenosine-5'-triphosphatase activities.
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PMID:The effect of thyrotropin releasing hormone on carbon dioxide laser induced lesion of the cerebral artery. 909 Jun 41

Cardiac involvement has not been a reported feature of congenital fiber-type disproportion myopathy. We describe two children, aged 13 years and 1 year, respectively, who presented with serious cardiac symptomatology in conjunction with congenital fiber-type disproportion. One child developed dilated cardiomyopathy and medically intractable congestive heart failure necessitating cardiac transplantation at the age of 13 years. The second (unrelated) child developed atrial fibrillation with rapid atrioventricular conduction requiring treatment with digoxin. Skeletal muscle biopsy findings in both children showed congenital fiber-type disproportion with no evidence of a structural, dystrophic, or metabolic myopathy. Adenosine triphosphatase (ATPase) reacted sections showed type I hypotrophy with a predominance of type I fibers, confirmed by histogram analysis. Examination of the heart from patient 1 at the time of transplantation confirmed dilated cardiomyopathy with hypertrophic myocardiocytes. Although cardiomyopathy is commonly associated with other childhood myopathies, to our knowledge it has not been a feature in reported cases of congenital fiber-type disproportion. We recommend close cardiac assessment, with annual electrocardiograms, of children with congenital fiber-type disproportion.
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PMID:Cardiac manifestations of congenital fiber-type disproportion myopathy. 1007 29

Adenosine 5'-triphosphatase (ATPase) plays a role in the process of energy conversion in the controlled hydrolysis of ATP. The effect of Ca2+ -binding protein on ATPase activity in the brain cytosol of rats of different ages was investigated. ATPase activity in the brain cytosol of 50-week-old rats was significantly decreased as compared with that of 5-week-old rats. The presence of calcium chloride (10(-5) and 10(-4) M) in the enzyme reaction mixture caused a significant increase in ATPase activity in the brain cytosol of rats of different ages. This increase was not altered by trifluoperazine (2x10(-5) M), an antagonist of calmodulin. Calmodulin (5 microg/ml), calbindin (5 microg/ml) or S-100A protein (10 microg/ml), a Ca2+ -binding protein, had no effect on ATPase activity. Meanwhile, regucalcin (10(-9) M), which is present in brain, significantly decreased ATPase activity in young and older rats. However, the effect of regucalcin was weakened by the presence of Ca2+ (10(-5) M). The addition of anti-regucalcin monoclonal antibody in the reaction mixture caused a significant elevation of ATPase activity; this increase was completely abolished by addition of regucalcin (10(-9) M). The present study suggests that regucalcin plays an inhibitory role in the regulation of ATPase activity in the brain cytosol of rats of different ages.
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PMID:Effect of calcium-binding protein on adenosine 5'-triphosphatase activity in the brain cytosol of rats of different ages: the inhibitory role of regucalcin. 1022 Feb 91

Proliferation, differentiation, and survival of erythroid progenitor cells are mainly regulated by stem cell factor (SCF) and erythropoietin (Epo). Using normal human progenitors, we analyzed the role of Ca2+-sensitive protein kinase C (PKC) subtypes and of G-protein-coupled receptor ligands on growth factor-dependent DNA synthesis. We show that stimulation of DNA synthesis by the two growth factors requires activation of PKCalpha. Inhibitors of Ca2+-activated PKC subtypes blocked the growth factor-induced 3H-thymidine incorporation. SCF and Epo caused no significant translocation of PKCalpha into the membrane, but treatment of intact cells with either of the two cytokines resulted in enhanced activity of immunoprecipitated cytosolic PKCalpha. Stimulation of PKC with the phorbol ester PMA mimicked the cytokine effect on DNA synthesis. Epo-, SCF-, and PMA-induced thymidine incorporation was potently inhibited by thrombin (half-maximal inhibition with 0.1 U/mL). This effect was mediated via the G-protein-coupled thrombin receptor and the Rho guanosine triphosphatase. Adenosine diphosphate caused a modest Ca2+-dependent stimulation of DNA synthesis in the absence of cytokines and specifically enhanced the effect of SCF. Cyclic 3', 5'-adenosine monophosphate exerted a selective inhibitory effect on Epo-stimulated thymidine incorporation. Our results define PKCalpha as major intermediate effector of cytokine signaling and suggest a role for thrombin in controlling erythroid progenitor proliferation.
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PMID:Erythropoietin- and stem cell factor-induced DNA synthesis in normal human erythroid progenitor cells requires activation of protein kinase Calpha and is strongly inhibited by thrombin. 1038 4


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