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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ATPase of matrix vesicles is not stimulated by calcium ions, nor do the vesicles have any capacity to metabolize glucose. ADPase of high activity is also present; thus vesicles cannot be a component of the conventional ATP cycle, in which energy is stored by phosphorylating ADP and released by hydrolyzing the resultant ATP. These results do not support speculations that matrix vesicles might function by concentrating calcium via an energy-dependent ion transport system such as those found in the plasma membrane and the sarcoplasmic reticulum. Matrix vesicles' alkaline phosphatase can be solubilized by treatment with certain detergents: sodium dodecyl sulfate (12 mM and 16 mM), cetylpyridinium chloride (14mM), and deoxycholic acid (DOC, 14 MM). The first two detergents denature the enzyme during storage whereas DOC does not. DOC will also solubilize ATPase and inorganic pyrophosphatase. Yields of the three enzymes are 85-95%. Dialysis of a DOC digest of vesicles removes DOC and 43% of protein, and also causes much of the alkaline phosphatase to become particulate once again.
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PMID:Matrix vesicles of bovine fetal cartilage: metabolic potential and solubilization with detergents. 12 41

The purpose of this study was to try to differentiate histochemically between the various enzymes which may catalyze the hydrolysis of ATP in developing rat dental tissues. Freeze cut and freeze dried sections of molar and incisor teeth were incubated in lead capture-based media at pH 5.0, 7.2 or 9.4 with one of the following substrates: beta-glycerophosphate, AMP, ADP, ATP, AMP-PNP and tetrasodium pyrophosphate. To establish the enzymatic nature of the hydrolysis parallel sections were incubated after prior fixation in either formaldehyde or glutaraldehyde. By comparing the enzymatic stainings obtained with the various substrates and at the different pH:s, it was concluded that ATP can be visibly hydrolyzed in rat dental tissues by alkaline phosphatase (stratum intermedium, apical part of maturation ameloblasts, basal part of all ameloblasts, odontoblasts and subodontoblastic layer), specific ATPase (apical and basal parts of secretory ameloblasts) and ATP pyrophosphatase and/or adenylate cyclase (stratum intermedium, odontoblasts). Acid phosphatase, specific ADPase, 5'-nucleotidase, inorganic pyrophosphatase, 3':5'-cyclic-AMP-phosphodiesterase and adenylate kinase on the other hand, seem not to be engaged in the ATP hydrolysis to such a degree as to complicate the interpretation of the histochemical staining. The alkaline phosphatase part of the ATP hydrolysis appeared to be rather insensitive to aldehyde fixation, while the hydrolysis effected by specific ATPase and ATP pyrophosphatase and/or adenylate cyclase was extinguished after fixation with formaldehyde for 4 h or glutaraldehyde for 10 min.
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PMID:Adenosine triphosphate hydrolysis in rat dental tissues. A histochemical study to differentiate the enzymes involved. 18 60

The intracellular location of a variety of enzymes was studied in Amoeba proteus with the use of electron microscopic cytochemical methods, in an attempt to assess the relationships between different membranous organelles. One group of enzymes, including nucleoside diphosphatases (IDPase, UDPase, GDPase, ADPase), carbamoyl phosphatase, alkaline phosphatase, and BAXD oxidase was localized mainly in the rough endoplasmic reticulum, nuclear envelope, and convex side of the Golgi apparatus. Esterase activity had a similar localization except that the Golgi apparatus was "stained" throughout most of its extent. A second group of enzymes was found in Golgi cisternae and vesicles, and in come vacuoles. This group included acid phosphatase, thiamine pyrophosphatase, and aryl sulfatase. Some enzymes previously detected in cytoplasmic membranes of other cells, including glucose-6-phosphatase, showed little or no activity in amoebae. The results suggest that there are chemical similarities and probable functional relationships between the rough endoplasmic reticulum, the nuclear envelope, and the convex side of the Golgi apparatus. On the other hand, the concave pole of the Golgi apparatus, aggregates of smooth tubules and vesicles, and the cell surface appear more closely related to one another than to the endoplasmic reticulum and the convex side of the Golgi apparatus. The cytochemical similarity between the Golgi apparatus and certain vacuoles such as food vacuoles may reflect the role of the Golgi apparatus in the formation of lysosomes. The locations of reaction products of the various enzymes in amoebae are compared with observations reported for other cell types.
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PMID:Relationships between membranous organelles in amoebae studied by electron microscopic cytochemical staining. 19 99

Human parotid glands, submandibular glands, and pleomorphic adenomas were examined by electron microscopic histochemistry. All epithelial cells of the normal salivary glands showed plasma membrane adenosine triphosphatase (ATPase) and inosine diphosphatase (IDPase) activity. However, myoepithelial cells reacted most intensely. Pleomorphic adenomas showed epithelial cells within solid and ductal portions of the tumors that were variably reactive for both ATPase and IDPase. Histochemical examination of the epithelial cells in the myxoid portions of the tumors did not provide conclusive evidence as to the nature of their progenitor cells. Surface-associated phosphatases (alkaline phosphatase, ATPase, and IDPase) cannot be reliably used as histochemical markers of salivary gland myoepithelial cells. Therefore, morphological and phosphatase histochemical studies that intend to examine the role of myoepithelial cells in salivary gland neoplasms must be interpreted with care.
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PMID:Phosphatase enzymes. Cytochemical study of pleomorphic adenoma and normal human salivary glands. 20 48

Phosphatase activities in sea urchin eggs and plutei were investigated by means of histochemical staining of immunoprecipitates. Two protein fractions were obtained by extraction in a hypotonic medium and by detergent treatment of the residual pellet. Three distinctly different phosphatase activities were discerned, nucleoside diphosphatase (EC 3.6.1.6.), acid phosphatase (EC 3.1.3.2.) and alkaline phosphatase (EC 3.1.3.1.). The nucleoside diphosphatase activity, which was confined to one antigen, was present in both water soluble and detergent extracts and at roughly the same concentration in eggs and plutei. By means of a monospecific antiserum the immunological identify of this antigen was established in all instances. The acid phosphatase activity, which was displayed by ten detergent extracted antigens in eggs, was only found in five detergent extracted antigens in plutei. This decrease in number of enzyme active antigens was also reflected by a general decrease in number of enzyme active antigens was also reflected by a general decrease in activity as assessed by quantitative determinations. Furthermore, by means of absorbed antisera it was established that two or three of the acid phosphatase active antigens were "egg specific". Another acid phosphatase active antigen, which was common to both developmental stages, was investigated by a monospecific antiserum. While this antigen was found in both soluble fractions, it was only enzymatically active when extracted with detergent. Alkaline phosphatase active antigens were only found in the detergent extract of plutei. However, immunoprecipitates with this activity appeared both with antiserum against unfertilized eggs and with antiserum against plutei. This suggests that the egg contained the antigens in an enzymatically inactive form.
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PMID:Phosphatase active antigens in sea urchin eggs and embryos. II. A comparison between the activities in unfertilized eggs and plutei. 23 75

The role of clathrin in retention of Golgi membrane proteins has been investigated. Prior work showed that a precursor form of the peptide mating pheromone alpha-factor is secreted by Saccharomyces cerevisiae cells which lack the clathrin heavy chain gene (CHC1). This defect can be accounted for by the observation that the Golgi membrane protein Kex2p, which initiates maturation of alpha-factor precursor, is mislocalized to the cell surface of mutant cells. We have examined the localization of two additional Golgi membrane proteins, dipeptidyl aminopeptidase A (DPAP A) and guanosine diphosphatase (GDPase) in clathrin-deficient yeast strains. Our findings indicate that DPAP A is aberrantly transported to the cell surface but GDPase is not. In mutant cells carrying a temperature-sensitive allele of CHC1 (chc1-ts), alpha-factor precursor appears in the culture medium within 15 min, and Kex2p and DPAP A reach the cell surface within 30 min, after imposing the nonpermissive temperature. In contrast to these immediate effects, a growth defect is apparent only after 2 h at the nonpermissive temperature. Also, sorting of the vacuolar membrane protein, alkaline phosphatase, is not affected in chc1-ts cells until 2 h after the temperature shift. A temperature-sensitive mutation which blocks a late stage of the secretory pathway, sec1, prevents the appearance of mislocalized Kex2p at the cell surface of chc1-ts cells. We propose that clathrin plays a direct role in the retention of specific proteins in the yeast Golgi apparatus, thereby preventing their transport to the cell surface.
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PMID:Selective and immediate effects of clathrin heavy chain mutations on Golgi membrane protein retention in Saccharomyces cerevisiae. 132 13

It was found that mitochondria from human placenta exhibited an ADPase activity with the following characteristics. The enzyme responsible for this activity was associated with the inner mitochondrial membrane. It was not released by treatment of the submitochondrial particles with solutions of high ionic strength. Maximal ADP hydrolysis was reached at pH 8. Specific inhibitors for alkaline phosphatase (L-phenylalanine), myokinase (P1,P5-di(adenosine-5')pentaphosphate), or 5'-nucleotidase (concanavalin A) did not decrease ADP hydrolysis. ATP synthesis from ADP by myokinase was about 13 nmol/mg/min, whereas ADP hydrolysis reached values around 500 to 550 nmol/mg/min, indicating that a myokinase-H+ATPase combination could not account for the observed rates of ADP hydrolysis. The activity was stimulated by Mg2+, but high concentrations of this cation produced inhibition. High ADP concentrations did not inhibit ADPase activity. Kinetic measurements of the activity in the submitochondrial particles showed that the true substrate was ADP-Mg. The kinetic studies showed V(app) values of 476 and 270 nmol/mg/min, and Kmapp values of 416 and 8.7 microM.
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PMID:Subcellular localization and properties of adenosine diphosphatase in human placenta. 147 Jun 6

This ultrastructural study was undertaken to determine the localization of cytochemically demonstrable blood-brain barrier (BBB)-associated enzymatic activities and of some nonenzymatic constituents in goat [corrected] brain microvascular endothelial cells (ECs) growing in vitro. Positive reactions for alkaline phosphatase (AP), 5'-nucleotidase (5'N), transport ATPase (Na+,K(+)-ATPase), and adenosine diphosphatase (ADPase) were present on both apical and basolateral plasma membranes (PMs) of the ECs. The reaction for calcium-dependent ATPase (Ca(2+)-ATPase) was less intense and was restricted to basolateral PM and associated plasmalemmal pits. These cells also revealed an abundance of anionic sites labeled with cationic colloidal gold (CCG) and Ricinus communis agglutinin 120 (RCA)-binding sites, specific for beta-D-galactosyl residues, on the apical PM. The labeling of the apical PM with Ulex europaeus agglutinin (UEA)-gold complex, specific for alpha-L-fucosyl residues, was negligible. When compared with results of cytochemical examination of the ECs of goat [corrected] brain capillary in vivo, these observations indicate that although cells cultivated in vitro retain at confluence the enzymatic activities typical for BBB-type ECS, they lose their characteristic (polar) localization. This loss is interpreted as a reflection of lost functional polarity of the microvascular endothelium in vitro resulting from deprivation of the normal influence of the components of brain parenchyma.
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PMID:Ultracytochemical characteristics of cultured goat brain microvascular endothelial cells [corrected]. 165 77

Mature secretory granules in paraneurons contain ATP amongst other small messenger molecules. In the islet organ such stores of adenine nucleotides readily can be demonstrated by means of the quinacrine fluorescence method. ATP is co-released together with other granule constituents when the major hormones are exocytosed. The distribution of ATP splitting enzymic activities was studied in the pancreas of the mouse and rat, in order to obtain information on the possible fate of this small messenger molecule. ATPase, ADPase, and AMPase (5'-nucleotidase) were demonstrated with lead precipitation methods, L-tetramisole was used to inhibit unspecific alkaline phosphatase (alPase); alPase activities were shown with tetrazolium methods, using 5-bromo-4-chloro-3-indoxyl phosphate as substrate. Most endothelial cells of the vascular bed, both in the exocrine and in the endocrine pancreas, are reactive for ATPase, ADPase, AMPase and alPase. Smooth muscle cells are strongly reactive for ATPase and AMPase, vascular adventitial fibroblasts (veil cells) stain for ATPase and alPase, as do some lamellar cells at the islets surface. Staining for ADPase serves as a selective method to demonstrate the vascular bed. Comparable results are obtained with the alPase reaction, though insular non-B-cells are also reactive. ATPase staining is less useful for demonstrating vascular connections because moderate reactivity of exocrine parenchyma and adventitial tissue obscures the picture. AMPase activity is strong in the venous segments of the capillary net and in collecting veins but the reaction obviously does not demonstrate significant portions of the residual capillary network. Weak AMPase activity is seen in the insular parenchyma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fate of ATP in secretory granules: phosphohydrolase studies in pancreatic vascular bed. 255 47

Retroplacental blood flow requires inhibition of coagulation in the absence of an endothelial lining. We confirmed that trophoblast releases an inhibitor of platelet aggregation which functions via degradation of adenosine diphosphate. This inhibitor appears to be deficient in some pregnancies with abruptio placentae and intrauterine growth retardation. Unimpeded retroplacental blood flow may depend upon the local inhibition of platelet aggregation. Placental tissue contains an inhibitor of platelet aggregation which appears to be an adenosine diphosphatase distinct from heat-stable alkaline phosphatase. Placental tissue from patients with abruptio placentae contains abnormally low amounts of this enzyme.
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PMID:Platelet inhibitory activity in placentas from normal and abnormal pregnancies. 281 99


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