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)

The activity of a purified cytosolic aminopeptidase (Mr 79,000) from monkey brain was stimulated about 4-fold by ATP-Mg2+. The stimulation was seen with either synthetic aminopeptidase substrates or natural peptides such as enkephalins. Both ATP and Mg2+ were required for stimulation, and ADP did not inhibit the stimulation. Non-hydrolysable analogues of ATP, deoxy-ATP and other nucleoside triphosphates stimulated to a lesser extent compared with ATP, whereas nucleoside mono- or di-phosphates were ineffective. The enzyme did not exhibit any ATPase activity. An ATPase inhibitor, orthovanadate, had no inhibitory effect on the ATP-Mg2+ stimulation. The aminopeptidase was not autophosphorylated by [gamma-32P]ATP and Mg2+, but in the presence of cyclic AMP-dependent protein kinase underwent phosphorylation on serine residue(s). Phosphorylation resulted in inactivation of the aminopeptidase activity, and also resulted in a decreased stimulation of the enzyme by ATP-Mg2+.
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PMID:Stimulation by ATP-Mg2+ and inactivation by cyclic-AMP-dependent phosphorylation of a cytosolic monkey brain aminopeptidase. 252 25

The metabolic pattern of aortic vein grafts in rats was studied by estimating histochemically the activity of the hydrolytic enzymes alfa-esterase, aminopeptidase, adenosine triphosphatase, acid phosphatase and alkaline phosphatase. The enzyme activity was lowest in the 16 hour and 1 day old grafts, and recovery was noted at three days. Five days after transplantation the enzyme activities were higher than in the non-transplanted veins. The rapid increase in enzymatic activity found in histochemical studies on wound healing was not seen in these vein grafts. At four weeks some grafts showed intimal thickening the activity of which did not exceed that of the other layers of the graft wall. At the end of the observation period of sixteen weeks most of the grafts showed intimal thickening, and this layer stained intensely especially for ATPase. The staining pattern of most of the grafts at sixteen weeks resembled that of the aortic media.
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PMID:Assessment of metabolic activity in aortic vein grafts in rats by histochemical examination of hydrolases. 252 49

Cytoplasmic granules obtained from toad urinary bladder epithelial cells were brought to buoyancy in a linear sucrose gradient. The gradient was loaded either with untreated cytoplasmic granules, or with granules treated with Na pyrophosphate (PPi), with digitonin, or with PPi and digitonin in succession. The following enzymes were assayed in the gradient subfractions: oligomycin-insensitive Mg++-ATPase, alkaline phosphodiesterase I, alkaline phosphatase, acid N-acetyl-beta-glucosaminidase, cytochrome oxidase, nucleoside diphosphatase (substrate, ADP), aminopeptidase (substrate, leucyl-beta-naphthylamide), and mannosyltransferase (acceptor, dolichylphosphate). Comparison of the density distributions of enzymes in untreated and treated preparations led to the characterization of 4 distinct subcellular entities. In agreement with the properties of mitochondria from other cell types, cytochrome oxidase buoys at 1.18 within a narrow density range and its behavior is not significantly altered by PPi or digitonin. Under all conditions, acid N-acetyl-beta-glucosaminidase is recovered over a broad density range in the lower part of the gradient and appears as a qualified lysosomal marker. Mg++-ATPase, alkaline phosphodiesterase I, and alkaline phosphatase belong to a group with the distinguishing features of a low equilibrium density in native cytoplasmic granules and a marked shift (+0.03 density units) after digitonin treatment. Such properties are typical of the plasma membranes. Part of the aminopeptidase activity probably also belongs to plasma membrane-derived elements. Minor differences between alkaline phosphatase and the other 2 members of that group make it possible that their distribution domains in the membrane do not overlap or coincide.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Subcellular fractionation of epithelial cells from toad urinary bladder. 2. Isopycnic centrifugation and effect of density perturbants. 255 74

The organization of the basolateral membrane domain of highly polarized intestinal absorptive cells was studied in adult rat intestinal mucosa, during development of polarity in fetal intestine, and in isolated epithelial sheets. Semi-thin frozen sections of these tissues were stained with a monoclonal antibody (mAb 4C4) directed against Na+,K+-ATPase, and with other reagents to visualize distributions of the membrane skeleton (fodrin), an epithelial cell adhesion molecule (uvomorulin), an apical membrane enzyme (aminopeptidase), and filamentous actin. In intact adult epithelium, Na+,K+-ATPase, membrane-associated fodrin, and uvomorulin were concentrated in the lateral, but not basal, subdomain. In the stratified epithelium of fetal intestine, both fodrin and uvomorulin were localized in areas of cell-cell contact at 16 and 17 d gestation, a stage when Na+,K+-ATPase was not yet expressed. These molecules were excluded from apical domains and from cell surfaces in contact with basal lamina. When Na+,K+-ATPase appeared at 18-19 d, it was codistributed with fodrin. Detachment of epithelial sheets from adult intestinal mucosa did not disrupt intercellular junctions or lateral cell contacts, but cytoplasmic blebs appeared at basal cell surfaces, and a diffuse pool of fodrin and actin accumulated in them. At the same time, Na+,K+-ATPase moved into the basal membrane subdomain, and extensive endocytosis of basolateral membrane, including Na+,K+-ATPase, occurred. Endocytosis of uvomorulin was not detected and no fodrin was associated with endocytic vesicles. Uvomorulin, along with some membrane-associated fodrin and some Na+,K+-ATPase, remained in the lateral membrane as long as intercellular contacts were maintained. Thus, in this polarized epithelium, interaction of lateral cell-cell adhesion molecules as well as basal cell-substrate interactions are required for maintaining the stability of the lateral membrane skeleton and the position of resident membrane proteins concentrated in the lateral membrane domain.
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PMID:Membrane domains of intestinal epithelial cells: distribution of Na+,K+-ATPase and the membrane skeleton in adult rat intestine during fetal development and after epithelial isolation. 255 43

In order to investigate the availability and release of enzymes from eosinophilic granulocytes in response to a variety of stimuli, guinea pig peritoneal eosinophils were obtained after repeated intraperitoneal injections of freeze-dried Trichinella spiralis larvae. The activities of the enzymes peroxidase, arylsulfatase B, beta-glucuronidase, aminopeptidase, histaminase, cytochrome c oxidase, acid phosphatase, adenosine triphosphatase and glucose 6-phosphatase, and the major basic protein (MBP) were studied histochemically and, in part, also biochemically. Eosinophils were incubated with the following substances: histamine, platelet activating factor, calcium ionophore, compound 48/80, leukotriene B4, prostaglandins E1, and E2, heparin, and eosinophil-chemotactic factors from neutrophils and lymphocytes. Eosinophils displayed a selective and stimulus-dependent enzyme and MBP reaction. Calcium ionophore and compound 48/80 provoked a release of cytotoxic major basic protein, partly associated with peroxidase release, while leukotriene B4 and eosinophil chemotactic factors caused histaminase and peroxidase release and activated leucinaminopeptidase. Heparin and calcium ionophore induced release of both MBP and histaminase. These data support the concept that eosinophils exhibit either inflammatory or cytotoxic, or antiinflammatory properties upon stimulation by various agents.
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PMID:Activation and release of enzymes and major basic protein from guinea pig eosinophil granulocytes induced by different inflammatory stimuli and other substances. A histochemical, biochemical, and electron microscopic study. 275 82

Plasma membrane vesicles were prepared from the basolateral face of pig small intestinal epithelial cells and were enriched in the activity of Na+-K+-ATPase (9-fold relative to the cell homogenate) and ranged in size from 0.15 to 0.40 micron diam. Incubation of somatostatin-14 and [125I-Tyr11]-somatostatin-14 with the vesicles at 37 degrees C resulted in rapid proteolytic degradation of the peptides. Metabolites were isolated by reverse-phase high-performance liquid chromatography and identified by amino acid composition. Cleavages between Ala1-Gly2, Phe6-Phe7, Phe7-Trp8, and Thr10-Phe11 were observed, indicative of aminopeptidase and endopeptidase action. Degradation was inhibited by 1,10-phenanthroline and by bacitracin, and in the presence of these inhibitors and at 21 degrees C binding of [125I-Tyr11]somatostatin-14 to the vesicles was observed. Binding was inhibited in a concentration-dependent manner by somatostatin-14 (half-maximal inhibition at 2.0 +/- 0.1 nM) and by somatostatin-28 (0.8 +/- 0.1 nM) but not by structurally unrelated peptides. The rate of degradation of [125I-Leu8, D-Trp22, Tyr25]somatostatin-28 by basolateral membrane was less than 20 fold that of [125I-Tyr11]somatostatin-14 and a two- to three-fold enhanced binding to the vesicles was observed. Analysis of the inhibition of binding of this analogue by somatostatin-28 indicates the presence of single class of binding site with Kd = 1.3 +/- 0.3 nM. Rapid degradation but no specific binding of somatostatin-14 by brush-border membranes was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Specific binding and degradation of somatostatin by membrane vesicles from pig gut. 287 63

Seminal plasma from 22 men attending an infertility clinic was subjected to preparative ultracentrifugation for 2 h at 105,000 g. The pelleted material as well as the supernatant thus obtained were investigated with regard to prostasome membrane-linked enzyme activities in relation to other semen parameters. The mean activity of Zn2+-dependent adenosine triphosphatase in the sedimented prostasome fraction was 1.45 +/- 1.02 mumol (range 0.29-4.79) orthophosphate released per milligram protein and 20 min, while the corresponding figures for the supernatant were 0.56 +/- 0.30 (range 0.12-1.29). Hence, 72% of the specific activity was sedimented, and 28% remained in the supernatant. The same pattern was recognized with regard to the other two enzymes investigated, although they displayed individual characteristics with regard to distribution after ultracentrifugation. The pelleted prostasome-linked mean aminopeptidase activity was 0.39 U/mg protein (81.9%), with only 0.087 U (18.1%) remaining in the supernatant. The corresponding figures for gamma-glutamyltransferase were 7.89 (60.4%) and 5.17 (39.6%) mu kat/g protein, respectively. The different enzyme activities in the prostasome fraction and supernatant, respectively, were interrelated to each other and correlated significantly with r values between 0.73 and 0.93 (p less than 0.001). It was concluded that a minor fraction of prostasomes remained in the supernatant after ultracentrifugation. A relationship existed between prostasomes and semen volume revealing a rather consistent pattern in that small volumes favoured the presence of comparatively more prostasomes in the supernatant and less prostasomes in the pelleted fraction than large volumes. In addition, the sperm concentration seemed to be another determinant of the distribution of prostasomes in seminal plasma on subsequent ultracentrifugation.
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PMID:Prostasome membrane associated enzyme activities and semen parameters in men attending an infertility clinic. 290 7

A stimulation by zinc ions of the hydrolysis of ATP by prostasomes prepared from human semen has been observed. Stimulation was maximal at a Zn2+/ATP stoichiometry of 0.5/l, and increasing this ratio resulted in a gradual decrease in ATPase activity. The pH optimum was 6.0. The apparent Km for Zn2+-dependent ATPase was 0.43 mmol/l and apparent Vmax 5.60 mumol/mg protein/20 min. Other divalent cations could replace Zn2+ as cofactor more or less effectively in the order Mn2+ greater than Cd2+ greater than Ba2+ greater than Sr2+. Potassium ions produced a further activation of the Zn2+-dependent ATPase system by about 10%. Such a stimulation was also attained to some extent by other monovalent cations as Rb+, NH4+, Li+ and to a lesser extent by Cs+. Orthovanadate in the concentration interval 5-1,000 mumol/l was inhibitory of the Zn2+-dependent ATPase system in a dose-dependent fashion. An aminopeptidase activity was also linked to the prostasomes. This enzyme activity was dramatically inhibited by 2 mmol/l orthophenantroline. A reactivation of the orthophenantroline-inhibited aminopeptidase activity was possible by adding Zn2+ to the reaction mixture. Hence, prostasomes contained ATPase as well as aminopeptidase activities both of which being dependent upon Zn2+. These two activities did not seem to be expressions of an ATP-dependent protease activity associated with prostasomes.
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PMID:Zinc ion stimulation of ATP cleavage by prostasomes from human seminal plasma. 297 4

In this work the biocompatibility of porous bioceramic implanted to the rabbit femoral bone was studied. The animals were killed 3, 6, 9, 14, 18 and 30 days after implantation and the callus with surrounding periosteum from the site of implant was taken for the studies. Morphological investigations of the callus were carried out up to the 30th day of healing of the bone tissue. Moreover, acid mucopolysaccharides level and activity of enzymes (acid and alkaline phosphatase, aminopeptidase, non-specific alpha-esterase, adenosine triphosphatase and succinate dehydrogenase) were studied up to the 18 day of the callus development. The results show that after bioceramic implantation, morphology of particular stages of the callus development, behaviour of acid mucopolysaccharides as well as localization and activity of enzymes are the same as in the normal healing process of the injured bone tissue. After 30 days total union of the mature bone tissue with bioceramic was established. We conclude that porous bioceramic satisfies the requirements for biomedical materials and may be safely used in the treatment of certain bone system diseases in humans.
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PMID:Application of porous bioceramic in experimental therapy of bone injuries. III. Dynamics of the callus development at the site of porous bioceramic implantation. Morphological, histochemical and histoenzymological studies. 323 60

1. The preparation of gram quantities of isolated epithelial-cell ;ghosts' from mucosal scrapings of rat small intestine is described. The method involves dispersing the tissue by gentle homogenization in 6% dextran in Krebs-Ringer phosphate, pH7.4, followed by filtration through nylon cloth and sedimentation by low-speed centrifuging. 2. The isolated epithelial-cell ;ghosts' contained all of the DNA, but only 52% of the protein and 53-57% of the RNA of the original homogenate. They contained most of the activity of the following enzymes found in the homogenate: aminopeptidase (71%); alkaline beta-glycerophosphatase (82%); invertase (92%); adenosine triphosphatase (93-116%); acid beta-glycerophosphatase (83%); nonspecific esterase (76%); succinate dehydrogenase (96%). Only small proportions of the total lactate-dehydrogenase (10%) and phosphoglucose-isomerase (2%) activities found in the homogenate were recovered in the isolated cell ;ghosts'. 3. The epithelial-cell ;ghost' preparation did not respire unless cofactors and substrates were added, and did not consume glucose or produce lactic acid from glucose. 4. The effect of varying the composition of the homogenization medium was studied. Concentrations of dextran (mol.wt. 15x10(4)) from 1 to 12%, solutions of dextrans (all at 6%) with mol.wt. varying between 3.6x10(4) and 2x10(6), and a solution of 8% polyethylene glycol (mol.wt. 4000) served equally well for the production of epithelial-cell ;ghosts'. Two of these solutions, however, 12% dextran (mol.wt.15x10(4)) and 6% dextran (mol.wt. 2x10(6)), were too viscous to allow the complete sedimentation of the cell ;ghosts' at low relative centrifugal forces. Omission of either Krebs-Ringer phosphate or dextran from the medium resulted in almost complete cell breakage during the homogenization. 5. The isolated cell ;ghosts' were used as a starting material for subcellular fractionation of rat intestinal mucosa by differential centrifugation. The distributions of protein and succinate-dehydrogenase activity among the fractions were compared with corresponding values in fractions isolated by differential centrifugation of mucosa homogenized in 0.3m-sucrose-5mm-EDTA, pH7.4. The method in which cell ;ghosts' were used as starting material gave a better separation and cleaner fractions than the method in which untreated mucosal scrapings were used.
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PMID:The isolation and properties of epithelial-cell "ghosts" from rat small intestine. 422 Sep 68


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