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:3.6.1.25 (triphosphatase)
1,529 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultrastructural distribution of adenosine triphosphatase and thiamine pyrophosphatase in synapses of rat's cerebral cortex was studied. Adenosine triphosphatase activity in some synaptic vesicles and mitochondria, on pre- and postsynaptic membranes, as well as in the postsynaptic thickening was established. The reaction specificity was proved by means of some controls: various concentrations of ouabain, NaF, NiCl2, cysteine, substrate free medium and non-specific substrates - cocarboxylase and beta-glycerophosphate. At the thiamine pyrophatase reaction, the enzyme positive product was found on the membrane of some clear synaptic vesicles, on the singl sacs of smooth endoplasmic reticulum in the axon terminal, and bouton cell membrane. Substrate free medium, addition of cystein and substitution of orininal substrate with adenosine triphosphate and beta-glycerophosphate as controls were used. The fine structure localization of both enzymes in synaptic structures suggests their important role in the synaptic function.
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PMID:Cytochemical localization of adenosine triphosphatase and thiamine pyrophosphatase in the synapases of rat's cerebral cortex. 14 1

Electron microscopic cytochemistry was used to determine the localization of five phosphatase enzymes-glucose-6-phosphatase, inosine diphosphatase, thiamine pyrophosphatase, acid phosphatase, and adenosine triphosphatase-in control human testes. Glucose-6-phosphatase occurred in the endoplasmic reticulum and nuclear envelope of Sertoli cells, Leydig cells and primitive spermatogonia, but was not observed in more advanced spermatogenic cells. The presence of glucose-6-phosphatase activity paralleled the presence of glycogen in spermatogenic cells, i.e., both occurred in type AL and AD spermatogonia but not in type AP or B spermatogonia or in more advanced spermatogenic cells. Inosine diphosphatase activity was found in the endoplasmic reticulum, nuclear envelope, and Golgi complex of Sertoli cells and all spermatogenic cells except late spermatids. Additionally, inosine diphosphatase activity was localized at the junctions between Sertoli cells and late spermatids, but was not associated with any other plasma membrane. Thiamine pyrophosphatase reaction product was found in the Golgi bodies of Sertoli cells and in spermatogenic cells through immature spermatids. Neither inosine diphosphatase nor thiamine pyrophosphatase was observed in the Golgi bodies of spermatids during acrosomal formation. Acid phosphatase activity was found in lysosomes of spermatogonia, spermatocytes, and spermatids, in lysosomes of Leydig cells, and in lysosomes, lipofuscin bodies, and Golgi cisternae of Sertoli cells. It is thought that Sertoli lysosomes play a role in the phagocytosis of degenerating germ cells; however, the role of spermatogenic or Leydig lysosomes is unknown. Adenosine triphosphatase activity occurred at the interfaces between two spermatogonia, and between Sertoli cells and spermatogonia, but was not observed in the spaces between two Sertoli cells, two spermatocytes, two spermatids, or between Sertoli cells and spermatocytes, or between Sertoli cells and spermatids.
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PMID:The fine structural localization of testicular phosphatases in man: the control testis. 17 58

Ultrastructural distribution of acid phosphatase and adenosine triphosphatase was studied in the receptor elements of HERBST and GRANDRY sensory corpuscles. Acid phosphatase activity was established in the elements of smooth and rough endoplasmic reticulum of perineural capsule cells, as well as in the secondary lysosomes of all cell types. Particular interest was paid on the activity of myelin-like dense bodies and some clear core vesicles belonging to the axoplasm of receptor nerve fibres. Adenosine triphosphatase activity was established on the membranes of receptor structures and pinocytotic vesicles. More deposits of electron dense material were localized on the axolemma of the non-myelinated portions of the receptor nerve fibres. The functional significance and importance of the both enzymes in the receptor structures was discussed.
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PMID:Cytochemical localization of acid phosphatase and adenosine triphosphatase in some avian mechanoreceptors. 21 19

The free Ca2+ concentrations in the nucleus ([Ca2+]n) and cytoplasm ([Ca2+]c) of cultured smooth muscle cells were estimated using the fluorescent dye indo-1 and the ACAS 570 confocal laser microscope. In resting DDT1MF2 smooth muscle cells [Ca2+]n was found to be lower than [Ca2+]c. Both values increased transiently in response to histamine (100 microM), but during this stimulation [Ca2+]n exceeded [Ca2+]c. Maximal increase of [Ca2+]n was observed in the center of the nucleus, and a maximal increase of [Ca2+]c was observed in the immediate vicinity of the plasma membrane. A similar response was obtained with other agonists, such as carbachol or ATP. Comparable results with ATP were obtained in cultured aorta cells. The differential rise of [Ca2+]n over [Ca2+]c in DDT1MF2 cells did not occur during either spontaneous release of Ca2+ or Ca2+ release induced by caffeine (7.5 mM). The differential rise during histamine stimulation was abolished by the presence of the intercalating substance ethidium bromide. Thapsigargin, a presumed specific inhibitor of the endoplasmic reticulum Ca(2+)-Mg(2+)-adenosine-triphosphatase, abolished the Ca2+ gradient between nucleus and cytosol at rest. During subsequent histamine stimulation the Ca2+ increase was largely blocked in both compartments and attained similar levels. We propose that the lower value of [Ca2+]n at rest is dependent on an active Ca2+ extrusion system. The differential rise of [Ca2+]n over [Ca2+]c during agonist stimulation can be explained by an influx of Ca2+ from perinuclear stores and/or by a release of intranuclear Ca2+ possibly mediated by a process dependent on the inositol lipid metabolism.
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PMID:Differences in regulation between nuclear and cytoplasmic Ca2+ in cultured smooth muscle cells. 138 89

In the present study, the structural and functional role of smooth endoplasmic reticulum was investigated in bullfrog olfactory axon terminals. Structural evidence obtained from this study indicated that this vesiculotubular organelle becomes a more elaborate network of anastomosing tubules near the nerve terminal, located in the olfactory lobe of frog brain. Further structural evidence suggested that membranes of the smooth endoplasmic reticulum pinch off to give rise to some electron-lucent vesicles of approximately 50 nm diameter (microvesicles). Ultrastructural cytochemistry was employed in the present study to demonstrate that olfactory axon terminal smooth endoplasmic reticulum actively sequesters Ca2+. However, a variable amount of electron-dense product (calcium oxalate) was associated with microvesicles located at a distance from the synapse, in contrast to those clustered near the synapse which usually did not contain this reaction product. Results from Ca2+-Mg2+-adenosine-5'-triphosphatase (ATPase) cytochemistry showed a similar pattern of distribution, with smooth endoplasmic reticulum being densely labeled with ATPase reaction product (lead phosphate), but aggregated microvesicles in the nerve terminal generally lacking this electron-dense product. Therefore, it is concluded that olfactory axonal smooth endoplasmic reticulum plays a role in the regulation of intraneuronal Ca2+ levels, and that the Ca2+-sequestering activity of this membranous organelle is dependent upon enzymatic hydrolysis of ATP. Conversely, the microvesicles, particularly those accumulated near the synapse, lack this Ca2+-pumping capacity. Thus, if some of the microvesicles originate from smooth endoplasmic reticulum membranes which are capable of pumping Ca2+, but these vesicles themselves lack this capacity, one can postulate that the Ca2+ pumps are either removed from the newly formed microvesicle membranes or are somehow incapacitated in situ in the membrane.
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PMID:Distribution and calcium-sequestering ability of smooth endoplasmic reticulum in olfactory axon terminals of frog brain. 350 Apr 27

Enzymatic activities associated with Golgi apparatus-, endoplasmic reticulum-, plasma membrane-, mitochondria-, and microbody-rich cell fractions isolated from rat liver were determined and used as a basis for estimating fraction purity. Succinic dehydrogenase and cytochrome oxidase (mitochondria) activities were low in the Golgi apparatus-rich fraction. On the basis of glucose-6-phosphatase (endoplasmic reticulum) and 5'-nucleotidase (plasma membrane) activities, the Golgi apparatus-rich fraction obtained directly from sucrose gradients was estimated to contain no more than 10% endoplasmic reticulum- and 11% plasma membrane-derived material. Total protein contribution of endoplasmic reticulum, mitochondria, plasma membrane, microbodies (uric acid oxidase), and lysosomes (acid phosphatase) to the Golgi apparatus-rich fraction was estimated to be no more than 20-30% and decreased to less than 10% with further washing. The results show that purified Golgi apparatus fractions isolated routinely may exceed 80% Golgi apparatus-derived material. Nucleoside di- and triphosphatase activities were enriched 2-3-fold in the Golgi apparatus fraction relative to the total homogenate, and of a total of more than 25 enzyme-substrate combinations reported, only thiamine pyrophosphatase showed a significantly greater enrichment.
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PMID:Isolation of a Golgi apparatus-rich fraction from rat liver. II. Enzymatic characterization and comparison with other cell fractions. 431 70

An odontogenic myxoma of a maxilla has been examined. Histochemistry of the mucosubstance indicated that hyaluronic acid and chondroitin sulphate were present. On ultrastructural examination many of the cells in the myxomatous tissue were seen with prominent rough endoplasmic reticulum, suggesting a secretory function, and possibly the myxomatous ground substance was produced by these cells. Cells containing collagen fibrils were found. Epithelial islands with intercellular spaces producing an arrangement similar to the stellate reticulum of the enamel organ were found, and possibly had developed from odontogenic epithelial rests. These islands were surrounded by a clear zone, outside which were cells with an increased prominence of adenosine-triphosphatase, nucleoside-diphosphatase, thiamine-pyrophosphatase, and often arylamidase reaction products. This probably represents a reaction of the mesodermal tissue to the epithelial islands. Possibly the epithelium exerts an inductive effect on the mesodermal tissue, and the myxomatous appearance may be the result of an aberrant development of mesodermal cells into ;myxoblasts' which secrete the myxomatous ground substance.
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PMID:Odontogenic myxoma: ultrastructural and histochemical studies. 435 41

Nucleoside mono-, di- and triphosphatase activities of highly purified endoplasmic reticulum (ER), Golgi apparatus, and plasma membrane fractions of rat liver were compared. The highest rates of hydrolysis were always in ER or plasma membrane. Golgi apparatus activity was intermediate between those of ER and plasma membrane. This relationship was true for both freshly isolated fractions and salt-extracted membranes. Detergent solubilization of the membranes, polyacrylamide gel electrophoresis of the solubilized proteins, and localization of the enzyme activities on the gel revealed bands of enzyme activity which had identical mobilities in all three membrane fractions as well as other bands of activity that occurred only in ER and to a lesser degree in the Golgi apparatus. Antibodies raised against one of the phosphatase bands of plasma membrane which was common to all three membrane fractions cross-reacted with the corresponding phosphatase band in ER and Golgi apparatus. The anti-nucleoside phosphatase was utilized in combination with pulse-chase techniques to investigate the flow kinetics of transfer of newly synthesized enzyme among different cell compartments. Label first appeared in nucleoside phosphatase within the ER. Maximum specific activity was observed at about 5 min after injection of label and was followed by rapid loss of label. This was followed by appearance of label in Golgi apparatus 15 to 25 min after injection of label and by subsequent rapid loss of label. Plasma membranes were labeled last with no evidence of either rapid accumulation of label or of rapid turnover. Flow of nucleoside phosphatase from its site of synthesis and insertion into the membrane at the endoplasmic reticulum to the plasma membrane via the Golgi apparatus is indicated but in a manner whereby a significant fraction of the protein may be processed (removed?) from the membrane concomitant with the flow process.
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PMID:Flow kinetics of a nucleoside phosphatase common to endoplasmic reticulum, Golgi apparatus, and plasma membrane of rat liver. 629 68

Electron microscopy cytochemistry has been used to study the cytoplasmic location of liposomes and lipid vesicles following specific antibody-dependent phagocytosis. The vesicle compositions were 94-99 mol% 'fluid' lipid (egg phosphatidylcholine or dimyristoylphosphatidylcholine at 37 degrees C or 'solid' lipid (dipalmitoylphosphatidylcholine at 37 degrees C). In some cases, 4 mol% phosphatidylserine was included in the vesicle membrane so as to vary the surface charge density. These vesicles undergo specific antibody-dependent phagocytosis by RAW264 macrophages when the lipid membranes contain 1-2 mol% dinitrophenyl lipid hapten in the presence of rabbit anti-dinitrophenyl IgG antibody. Internalized lipid vesicles can be visualized with the electron microscope when ferritin is trapped in the internal aqueous compartments prior to internalization. The lipid vesicles were demonstrated to be internal to the macrophage plasma membranes by selectively staining the plasma membranes with Ruthenium red. The cytoplasmic location of vesicles and liposomes was studied by electron microscopic staining for activities of the following enzymes: (1) acid phosphatase; (2) inorganic trimetaphosphatase; (3) adenosine triphosphatase; and (4) glucose-6-phosphatase. The first two enzymatic activities were found in association with ferritin-containing vesicles after antibody-dependent phagocytosis, showing the formation of vesicle-containing phagolysosomes. Adenosine triphosphatase and glucose-6-phosphatase were primary not associated with the vesicles, suggesting a minimal association of vesicles with plasma membrane, Golgi, endoplasmic reticulum and perinuclear cisternae. Phagosome-lysosome fusion did not appear to depend on the type of target lipid vesicle or liposome, on the 'fluidity' of the target membrane, or the presence of phosphatidylserine in the target membrane.
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PMID:Cytochemical study of liposome and lipid vesicle phagocytosis. 668 37

A nuclear scaffold (NS) protease has previously been implicated in production of the M(r) 46,000 ATP-binding protein in NS (which may acquire nucleoside triphosphatase activity and participate in nucleocytoplasmic transport) by cleavage of a subset of lamins A/C. In a preceding paper (G. Clawson, L. Norbeck, C. Hatem, C. Rhodes, P. Amiri, J. McKerrow, S. Patierno, and G. Fiskum, Cell Growth & Differ., 3: 827-838), this NS protease was identified as a novel, Ca(2+)-regulated serine protease, which was found only in the NS and which appears to represent a unique multicatalytic protease complex. Based upon its predominantly chymotrypsin-like substrate preference, a peptide-chloromethylketone inhibitor (succinyl-AAPF-chloromethylketone, AAPFcmk) was identified. AAPFcmk showed a KI = 56 nM for the NS protease versus 1.4 microM for the endoplasmic reticulum activity. Treatment of C3H/10T1/2 mouse embryo fibroblast cells with 1 microM AAPFcmk produced effects which were confined to the nuclear (and to a lesser extent the endoplasmic reticulum) compartment. In this report, we examine the effects of the AAPFcmk inhibitor on cellular transformation and growth. Growth of C3H/10T1/2 cells was decreased by 34% and 56% at 25 microM and 50 microM AAPFcmk, respectively. Growth inhibition occurred without any major change in DNA content distribution, suggesting effects throughout the cell cycle. Growth inhibition was not observed at lower (< or = 10 microM) concentrations, which decreased transformation of C3H/10T1/2 fibroblasts in a dose-dependent manner by up to 90%, even at femtomolar concentrations of AAPFcmk (in the absence of growth inhibition). Inclusion of irrelevant inhibitors was without affect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:An inhibitor of nuclear scaffold protease blocks chemical transformation of fibroblasts. 839 99


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