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

---

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

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.
...
PMID:Adenosine triphosphate hydrolysis in rat dental tissues. A histochemical study to differentiate the enzymes involved. 18 60

The possible role of cytoplasmic microtubules in the renal handling of phosphate and its regulation by parathyroid hormone (PTH) was evaluated with colchicine, a microtubule-disrupting agent. Colchicine-treated rats were thyroparathyroidectomized (TPTX) and subsequently infused with PTH. Treatment with a total dose of 1 mg colchicine had no effect on glomerular filtration rate or fractional excretions of sodium and potassium. Fractional excretion of phosphate in colchicine-treated TPTX rats was significantly higher compared with TPTX controls. After PTH infusion, control rats responded with increases in fractional excretion of phosphate and urinary cyclic AMP but colchicine-treated rats had variable and insignificant changes in both parameters. Fractional excretion of sodium and potassium did not change significantly after PTH. Renal cortical activities of cyclic AMP phosphodiesterase, soluble alkaline phosphatase, cytochrome oxidase, leucine aminopeptidase, or basal adenylate cyclase were not significantly affected by colchicine treatment. On the other hand, stimulation of adenylate cyclase by a submaximal dose of PTH was markedly decreased in colchicine-treated rats, and the activity of membrane-bound alkaline phosphatase was also significantly decreased. The binding of radioactive colchicine in renal cortical extracts from rats treated with colchicine was significantly diminished. These results suggest that disruption of cytoplasmic microtubules in renal cortical cells interferes with phosphate transport and its regulation by PTH.
...
PMID:Effect of colchicine on urinary phosphate and regulation by parathyroid hormone. 18 12

Cardiac myofibrils were purified from canine myocardium, and the regulatory proteins (troponin + tropomyosin) were extracted and shown to contain endogenous cyclic AMP-dependent protein kinase activity. Other cyclic nucleotide stimulated the protein kinase activity but only at higher concentrations. The enzyme was able to catalyze phosphorylation of conventional substrates such as histones and casein as well as a component of the regulatory protein fraction with a molecular weight of 28,000 daltons. Endogenous phosphorylation required the presence of Mg2+ and was inhibited by Ca2+. A protein kinase inhibitor obtained from skeletal muscle inhibited the cyclicAMP-dependent phosphorylation. Escherichia coli alkaline phosphatase dephosphorylated the endogenous substrates. The level of phosphorylation found is severalfold higher than we have previously reported. A protein kinase, with its close association with the regulatory proteins, seems to be well suited to transmitting the message from the cyclic AMP to the regulatory proteins, a phenomenon that may influence the cardiac contractility via the troponin phosphorylation. The inhibitory effect of troponin on actomyosin might be changed by its state of phosphorylation.
...
PMID:Phosphorylation of cardiac regulatory proteins by cyclic AMP-dependent protein kinase. 18 66

A procedure for the purification of cholesterol ester hydrolase from bovine adrenal cortical 105000 x g supernatant is described. Preincubation of a crude enzyme extract with [gamma-32P]ATP followed by purification resulted in the isolation of a phosphorylated preparation of cholesterol ester hydrolase. The phosphorylated cholesterol ester hydrolase appeared to be composed of 4 subunits, each having a molecular weight of 41000 +/- 280, only one of which may be phosphorylated. Preincubation of the crude enzyme preparation with [alpha-32P]ATP followed by purification did not produce a phosphorylated preparation of cholesterol ester hydrolase. Cyclic-AMP-dependent protein kinase, cyclic AMP, ATP and magnesium ions were required for activation of purified cholesterol ester hydrolase in vitro and the time course of activation closely paralleled the time course of phosphorylation of the enzyme. The addition of ATP, cyclic AMP and magnesium ions to the bovine adrenal cortical 105000 x g supernatant produced a 2.5-fold stimulation in cholesterol ester hydrolase activity. This stimulation was abolished if protein kinase inhibitor was added prior to the addition of ATP cyclic AMP and magensium ions. The addition of magnesium ions or calcium ions to a crude preparation of cholesterol ester hydrolase was found to inhibit activity; however the same additions made to a purified preparation of cholesterol ester hydrolase were not inhibitory. The decrease in cholesterol ester hydrolase activity on incubation with magnesium ion was accompanied by a loss of 32P radioactivity from the protein. Preincubation of a crude preparation of cholesterol ester hydrolase with alkaline phosphatase resulted in a deactivation of cholesterol ester hydrolase. It is suggested that bovine adrenal cortex cholesterol ester hydrolase is activated by a phosphorylation catalysed by a cyclic-AMP-dependent protein kinase. Deactivation of cholesterol ester hydrolase is accomplished by dephosphorylation catalysed by a phosphoprotein phosphatase, dependent on magnesium or calcium ions.
...
PMID:Purification and control of bovine adrenal cortical cholesterol ester hydrolase and evidence for the activation of the enzyme by a phosphorylation. 18 99

Myocardial acidic non-histone nuclear proteins (NHPs) contain endogenous protein kinase activity. Phosphocellulose chromatography of purified NHPs identifies nine separate peaks of protein kinases which can phosphorylate both endogenous and exogenous substrates to a variable degree; endogenous NHPs are the best substrates. Cyclic AMP-stimulated protein kinase induced phosphorylation of endogenous and exogenous substrates; the extent of this stimulation varied according to the protein kinase fraction and substrate used. Cyclic AMP also enhanced NHP-induced stimulation of RNA polymerase activity. This enhancement was dependent on protein kinase-induced phosphorylation of NHPs since it was prevented by alkaline phosphatase pretreatment. It is concluded that nuclear protein kinases regulate myocardial RNA synthesis by enhancing phosphorylation of NHPs and that this regulation is under cyclic AMP control.
...
PMID:Adenosine 3',5'-monophosphate-dependent protein kinases of myocardial non-histone nuclear proteins. 19 45

The effect of citrinin poisoning on rabbit kidney alkaline phosphatase was investigated. After seven days administration of citrinin (2 mg/kg body weight daily) the animals were sacrificed and the level of enzymes estimated in serum and kidney. Serum enzymes showed no variation in activity in the citrinin-treated animals, but in kidney, alkaline phosphatase activity decreased significantly. The decreased activity was mainly associated with the cytoplasmic fraction and in fractions Ib and II. The enzyme II obtained from citrinin-treated animal showed no kinetic difference in substrate specificity, inhibition by phenylalanine, phosphate, sodium-EDTA and Zn2+ ions, activation by Mg2+ ions, thermal inactivation and electrophoretic mobility to that of control Enzyme II. Immunological studies showed that the decrease in enzyme activity was due to existence of inactive enzyme protein. Hormones like cyclic AMP, prostaglandin E1 and parathyroid hormone reversed the decreased enzyme activity due to citrinin poisoning in mouse and rabbit. This study favours the possible existence of active and inactive forms of alkaline phosphatase in the system.
...
PMID:The mechanism of action of citrinin on rabbit kidney alkaline phosphatase activity in vivo. 19 68

The effect of carbon-tetrachloride poisoning and the protection caused by AMP were studied. A single dose of CCl4 has resulted in a rapid development of a fatty liver, a considerable increase in serum enzymes, glutamic oxalacetic and pyruvic transaminases as well as serum-alkaline phosphatase. Total serum protein showed a tendency to decrease accompanied by a decrease in A/G ratio. Administration of adenosine-5-monophosphate prevented the increase in serum-alkaline phosphatase and increased the A/G ratio. There was, however, a slight but significant decrease in serum GOT and GPT within the 24-hrs. period of study, but it remained still higher than that of the control. AMP lowered liver fat without complete protection against the development of fatty liver.
...
PMID:Effect of AMP on acute carbon-tetrachloride hepatotoxicity. 20 15

A preparation of poly(adenosine diphosphoribose) synthase obtained from pigeon liver nuclei has been used to make poly(adenosine diphosphoribose) with an average chain length of 20. Digestion of the purified poly(adenosine diphosphoribose) with snake venom phosphodiesterase (oligonucleate 5'-nucleotidohydrolase; EC 3.1.4.1) gave the monomer, 2'-(5"-phosphoribosyl)-5-AMP. After purification of the monomer on a Dowex-1 column, further digestion with alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum); EC 3.1.3.1] yielded the dephosphorylated product, 2'-ribosyl adenosine. Nuclear magnetic resonance spectra at 360 MHz of the 2'-ribosyl adenosine were obtained in [2H6]dimethylsulfoxide, which allows direct observation of the hydroxyl protons. These spectra show the absence of the adenosine 2'-hydroxyl proton, thus confirming the 2' position as the site of attachment of the ribose to the adenosine moiety. Comparison of the coupling constants and the chemical shifts of the ribose hydroxyl protons of 2'-ribosyl adenosine with the model compounds alpha- and beta-methylribofuranoside establishes an alpha (1" leads to 2') glycosidic linkage in the monomer. No evidence was found for heterogeneity in either the site of attachment or configuration of the linkage in the 2'-(5"-phosphoribosyl)-5'-AMP.
...
PMID:Structure of a poly (adenosine diphosphoribose) monomer: 2'-(5"-hosphoribosyl)-5'-adenosine monophosphate. 20 34

The rat small bowel was perfused in vivo and ex vivo in the absence of biliary and pancreatic secretion. Intraluminal release of sucrase, alkaline phosphatase, aminopeptidases and enterokinase was significantly increased after administration of pentagastrin, caerulein and glucagon at doses ranging between 1 pg and 10 microgram. This suggests that there is a direct hormonal stimulation of the intestinal mucosa. This effect might at least partly be mediated through cyclic AMP since dibutyryl derivates of this cyclic nucleotide exerted a significant stimulatory effect on intraluminal release of proteins, sucrase and enterokinase, although the pattern of enzyme was quite different from the effect produced by the three peptides.
...
PMID:Hormonal stimulation of intestinal brush border enzymes release. 20 30

In six infants aged between 4 and 8 months with chronic renal failure, we have studied blood levels of calcium (Ca), phosphorus (P), alkaline phosphatase, immunoreactive parathyroid hormone (PTH), and calcitonin (CT), as well as urinary excretion of Ca, P, hydroxyproline and cyclic AMP under basal conditions and during an infusion of 20 mg/kg of 10% Ca gluconate in normal saline over 4 h. Under basal conditions four infants had normal serum Ca and P values, alkaline phosphatase levels at the upper limit of normal, and very high PTH (range: 1450--2550 pg Eq/ml) and CT (range: 700--1900 pg/ml) levels. The urinary Ca excretion was low, whereas the urinary excretion of P, hydroxyproline and cyclic AMP was high. During Ca infusion, the total serum Ca and CT levels increased, PTH fell without however reaching the normal upper limit, and urinary P and cyclic AMP excretion decreased. In two infants with osteodystrophy and the highest levels of PTH (2900 and 3500 pg Eq/ml respectively) there was no suppression of PTH during Ca infusion.
...
PMID:Parathyroid hormone and calcitonin secretion in uraemic infants. 21 73


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---