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)

Alkaline phosphatase (AP) is one of the enzymes which is highly active in the plasmalemma of endothelial cells (ECs) of BBB-type microvessels. In the ECs of non-BBB type vessels, the reaction for AP (and other phosphatases) is negative (e.g. choroid plexus, area postrema, hypophysis). After BBB damage, the leakage of the vessels can be demonstrated by the use of horseradish peroxidase (HRP). Concomitantly, changes in polar distribution of AP in the ECs occur, paralleled by the appearance of numerous pinocytic vesicles, deep invaginations of the plasmalemma and channel-like structures. The delimiting membranes of these structures possess AP, 5'-nucleotidase, nucleoside diphosphatase and Na+, K+-ATPase activities. These observations suggest that the redistribution of plasmalemma bound enzymes from luminal to abluminal surface results from membrane flow associated with formation of pinocytic vesicles and channel-like structures in affected ECs. In the area of brain where the process of resolution of brain edema occurs, the shift of the enzymatic activity from luminal to abluminal plasmalemma of the ECs is observed probably because of the need to remove various solutes present in the edematous fluid. The appearance of positive reaction for AP in the abluminal side of the EC can be a reflection of the changed functional polarity of these cells associated with reverse transport of solutes from brain, back into the blood stream.
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PMID:Enzyme cytochemistry of blood-brain barrier (BBB) disturbances. 630 82

We studied the uptake of D-glucose and L-tryptophan by the small intestine and estimated the activities of the intestinal brush border enzymes (sucrase, lactase, NA+-K+-ATPase and alkaline phosphatase) and lysosomal enzymes in rats receiving T-2 toxin orally. considerable decrease occurred in glucose and tryptophan uptake and in brush border sucrase, lactase and (Na+-K+)-ATPase. Alkaline phosphatase activity and release of lysosomal enzymes (acid phosphatase and acid ribonuclease) was unchanged.
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PMID:Effects of T-2 toxin on glucose and tryptophan uptake and intestinal mucosal enzymes. 671 77

1. Duodenal mucosa was collected from control rats and from animals which had received cysteamine, cysteamine plus cimetidine or pentagastrin. Animals which received cysteamine with or without cimetidine developed acute duodenal ulcers. Cysteamine treatment resulted in gastric acid hypersecretion, which was largely abolished by concurrent cimetidine administration. 2. Activities of enzymes implicated in bicarbonate secretion, HCO3--activated ATPase, carbonic anhydrase and Na+ + K+-activated ATPase, were measured in the duodenal mucosa of control rats and animals 24 h after subcutaneous administration of cysteamine. Assays of these enzymes in duodenal mucosal homogenates from animals with cysteamine-induced ulcers showed significant decreases in HCO3--activated ATPase and carbonic anhydrase activities compared with controls. 3. Alkaline phosphatase activity also fell significantly in the cysteamine-treated animals, and possibly reflects the HCO3---activated ATPase activity in the brush-border membrane. In contrast, activities of other marker enzymes from the brush-border membrane and from several intracellular organelles were unchanged, indicating an absence of gross organelle pathology in this experimental model. 4. Similar changes in enzyme activity were not caused by treatment with pentagastrin. Administration of cimetidine with the cysteamine did not protect the animals against ulceration, and the activity of HCO3--activated ATPase was persistently decreased. However, the carbonic anhydrase activity was unaltered in this latter group, compared with controls. 5. These findings suggest that in cysteamine-induced duodenal ulceration both gastric acid hypersecretion and impaired duodenal resistance occurs. It is suggested that decreased activities of key enzymes implicated in HCO3--secretion may reflect the biochemical basis for the decreased mucosal resistance.
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PMID:Mucosal enzyme activities, with special reference to enzymes implicated in bicarbonate secretion, in the duodenum of rats with cysteamine-induced ulcers. 682 66

An enzyme histochemical and cytochemical study of normal dermal microvasculature showed that respiratory enzymes, lipase and non-specific esterase occurred in all vascular segments. Lysosomal enzymes were also widely distributed and acid phosphatase activity was localized in lysosomes, Golgi apparatus and small portions of endoplasmic reticulum of both endothelial cells and pericytes. Alkaline phosphatase activity, however, was confined to the arterial side and tip of the capillary loop where it occurred in vesicles along the luminal surface of the endothelium and in junctions between endothelial cells. The localization of nucleoside phosphatase activity within the endothelium varied according to substrate; with adenosine triphosphate as substrate, the reaction product occurred in vesicles distributed throughout the endothelial cells; with adenosine diphosphate it was limited to vesicles along the luminal surface; and with adenosine monophosphate, activity was mostly localized to the lateral surfaces of endothelial cells. These findings suggest functional variation between different vascular segments and between various components of the endothelium. Attempts to demonstrate a specific Na+K+ adenosine triphosphatase (transport ATPase) within the endothelium were not successful.
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PMID:Human dermal microvasculature: II. Enzyme histochemical and cytochemical study. 723 11

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

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

Alkaline phosphatase from rat osseous plate is allosterically modulated by ATP, calcium and magnesium at pH 7.5. At pH 9.4, the hydrolysis of ATP and PNPP follows Michaelis-Menten kinetics with K0.5 values of 154 microM and 42 microM, respectively. However, at pH 7.5 both substrates exhibit more complex saturation curves, while only ATP exhibited site-site interactions. Ca(2+)-ATP and Mg(2+)-ATP were effective substrates for the enzyme, while the specific activity of the enzyme for the hydrolysis of ATP at pH 7.5 was 800-900 U/mg and was independent of the ion species. ATP, but not PNPP, was hydrolyzed slowly in the absence of metal ions with a specific activity of 140 U/mg. These data demonstrate that in vitro and at pH 7.5 rat osseous plate alkaline phosphatase is an active calcium or magnesium-activated ATPase.
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PMID:Allosteric modulation by ATP, calcium and magnesium ions of rat osseous plate alkaline phosphatase. 839 76

Alkaline phosphatase is the marker enzyme for matrix vesicles, extracellular organelles that play a major role in primary bone formation and calcification. Recently, we developed osteosarcoma x fibrosarcoma hybrids in which alkaline phosphatase expression was greatly reduced, a phenomenon known as extinction. In the present study, we used to cell hybrids, LTA-1 and LTA-5, constructed from a human osteoblast-like osteosarcoma. TE85, and a mouse fibrosarcoma, La-t-, to examine the differential distribution of alkaline phosphatase between matrix vesicles and the plasma membrane, postulated to be the parent membrane from which matrix vesicles are derived. While alkaline phosphatase in plasma membranes was extinguished, enzyme activity in matrix vesicles from LTA-1 hybrid cells was 34.2% of that present in matrix vesicles from the TE85 parent cells and 200 times that found in La-t- matrix vesicles. Matrix vesicles from LTA-5 had alkaline phosphatase levels similar to La-t-. When other membrane enzymes (phospholipase A2, 5'-nucleotidase, and Na+/K+ ATPase) were examined, hybrid matrix vesicle and plasma membrane levels were similar to those of TE85 and significantly higher than in La-t- membrane fractions. Northern analysis detected mRNA for alkaline phosphatase in TE85 cells, but not in the hybrids or La-t- cells. In contrast, reverse transcription-polymerase chain reaction (RT-PCR) revealed alkaline phosphatase mRNA in the hybrid cells, but at very low levels. Taken together, the data indicate that regulation of plasma membrane and matrix vesicle alkaline phosphatase is independent and suggest that matrix vesicle biogenesis is independent and distinct from that of plasma membrane biogenesis. Analysis of 1B- and 1L-type alkaline phosphatase mRNA by RT-PCR showed that alternate promoter usage of the alkaline phosphatase gene was not responsible for the differential localization of this enzyme in matrix vesicle. Thus, it is likely that matrix vesicle and plasma membrane alkaline phosphatase are regulated differently at a post-transcriptional level.
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PMID:Osteosarcoma hybrids can preferentially target alkaline phosphatase activity to matrix vesicles: evidence for independent membrane biogenesis. 859 37

The plasma membrane H+-ATPase was purified from tobacco cells (line BY-2). After solubilization by lysophosphatidylcholine followed by separation on a glycerol gradient, a fraction with a high specific activity of 9 micromol ATP x min(-1) x mg protein(-1) was obtained, in which the H+-ATPase polypeptide represented at least 80% of the protein. The incubation of this fraction in the presence of alkaline phosphatase increased H+-ATPase activity by 40%, in a manner consistent with dephosphorylation of the enzyme itself. The hydrolytic activity of the solubilized enzyme and its proton translocating activity, after reconstitution into proteoliposomes, were stimulated to the same extent. Alkaline phosphatase treatment was also accompanied by a 92% decrease in the H+-ATPase phosphothreonine content, whereas the phosphoserine residues were almost unaffected. The dephosphorylation induced a slight decrease of the affinity of the enzyme towards ATP. The purified enzyme was not activated by lysophosphatidylcholine addition nor by trypsin-mediated proteolysis, two treatments reported to release the inhibitory control by the C-terminal domain of the H+-ATPase and to increase the affinity of the enzyme towards ATP. Based on these results, the regulatory phosphorylation evoked by alkaline phosphatase most likely differs from the autoinhibitory control of the H+-ATPase by its C-terminal domain.
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PMID:Dephosphorylation activates the purified plant plasma membrane H+-ATPase--possible function of phosphothreonine residues in a mechanism not involving the regulatory C-terminal domain of the enzyme. 949 23

The present study evaluated the effect of low doses of electron radiation on the activity of phosphodiesterases in granulation tissue. In order to induce growth of granulation tissue, a PVC sponge disk was introduced under the dorsal skin of 84 Wistar rats. The rats were divided in two groups, control and irradiated. The enzymatic activity was evaluated according to the evolution of the granulation tissue after 5, 7, 10, 14, 17, 20 and 24 days. Irradiation was carried out 3 days after the implantation of the sponge, by means of a linear accelerator, with energy of 6 MeV, and dose of 1.0 Gy. The results of this study showed that 5'-nucleotidase and ATPase had their activity directly affected by irradiation only in the beginning of the tissue repairing process. Alkaline phosphatase did not suffer any direct effect of irradiation. It is possible that the main factor has been the damage of the cellular components responsible for the growth of granulation tissue, which determine the production of enzymes according to the necessity.
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PMID:[Activity of phosphodiesterases in granulation tissue treated with electron irradiation -- experimental study on rats]. 1170 70


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