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 3 or 4 phosphate ester of dopamine (PD) was hydrolyzed by homogenates of rat tissues to give inorganic phosphate (Pi) and dopamine. The rate of hydrolysis of PD by kidney homogenates was increased by exogenous MgCl2 but not CaCl2 or KCl. The activity of brain, heart or liver homogenates was insensitive to the added salts. Several lines of evidence indicate that alkaline phosphatase activity contributes to the high rate of PD hydrolysis by the kidney but not brain homogenate. The intravenous infusion of PD at 12 mumole/kg in one hr to anesthetized rats increased the dopamine content of the plasma, kidney and heart without altering brain or liver dopamine. The results suggest that PD may be more effective than dopamine for increasing dopamine levels of the kidney. In addition, the hydrolysis of PD by brain homogenates, which is independent of alkaline phosphatase activity, suggests that specific enzymes exist for the metabolism of PD.
...
PMID:Pharmacologic properties of a phosphate ester of dopamine. 358 52

Hepatic branched-chain 2-oxoacid dehydrogenase is inactivated by nutritional alterations. Reactivation occurs during preincubation of intact mitochondria in the presence of rat liver cytosolic supernatant. Cytosolic supernatant contains two factors capable of reactivating the enzyme. On gel-filtration (Sephadex G-100), one factor (AF1) elutes in the molecular range of 35,000-40,000 and the other factor (AF2) elutes slightly later than inorganic phosphate. AF2 is stable against heat denaturation and treatment with proteinases. It is destroyed by alkaline phosphatase and in the presence of Ap5A, atractyloside, CaCl2 and NaF its stimulatory effect on branched-chain 2-oxoacid dehydrogenase activity is abolished. Inhibition of activation by NaF suggests that a phosphatase might be involved in the activation process.
...
PMID:Activation of hepatic branched-chain 2-oxoacid dehydrogenase by rat liver cytosolic supernatant. 376 11

Incubation of rat liver nuclear envelopes with [gamma-32P]ATP resulted in the synthesis of phosphatidylinositol-[4-32P]phosphate (PIP). Degradation of endogenously labeled PIP was observed upon the dilution of the labeled ATP with an excess of unlabeled ATP. This degradation was most rapid in the presence of EDTA, and was inhibited by MgCl2 and CaCl2. To further characterize the degradative activity, phosphatidylinositol[4-32P]phosphate and phosphatidylinositol [4,5-32P]bisphosphate (PIP2) were synthesized and isolated from erythrocyte plasma membranes. The 32P-labeled phospholipids were then resuspended in 0.4% Tween 80, a detergent that did not inhibit degradation of endogenously labeled PIP, and mixed with nuclear envelopes. [32P]PIP and [32P]PIP2 were degraded at rates of 2.25 and 0.04 nmol min-1 mg nuclear envelope protein-1, respectively. Only 32P was released from phosphatidyl[2-3H]inositol-[4-32P]phosphate, indicating that hydrolysis of PIP was due to a phosphomonoesterase activity (EC 3.1.3.36) in nuclear envelopes. Similarly, anion-exchange chromatographic analysis of the water-soluble products released from [32P]PIP indicated that inorganic phosphate was the sole 32P-labeled product. Hydrolysis of PIP was most rapid at neutral pH, and was not affected by inhibitors of acid phosphatase or alkaline phosphatase. Hydrolysis of PIP was also not inhibited by nonspecific phosphatase substrates, such as glycerophosphate, p-nitrophenylphosphate, AMP, or glucose 6-phosphate. Hydrolysis was stimulated by putrescine, and was inhibited by inositol 2-phosphate, spermidine, spermine, and neomycin.
...
PMID:Characterization of a phosphatidylinositol 4-phosphate-specific phosphomonoesterase in rat liver nuclear envelopes. 609 90

The ATPase activity of rabbit-kidney brush border can be activated almost equally well by Ca2+ and Mg2+ and, therefore, should be called (Ca2+ or Mg2+)-ATPase. This enzyme was solubilized and enriched 14-fold by the following steps: pretreatment with papain removed 69% of alkaline phosphatase without attacking a significant portion of the ATPase activity. Addition of 1% cholate removed 65% of the protein but no ATPase activity. The combination of cholate (0.5%) and deoxycholate (0.4%) solubilized most of the ATPase activity and most of the remaining protein. A column chromatography of the extract on Sepharose CL-2B resulted in an 6.5-fold increase of specific ATPase activity. A precipitation by ammonium sulfate (40% saturation) produced an additional 1.9-fold increase. The yield of this partial purification was 16%. Towards the nucleotides UTP and GTP the enzyme showed an activity slightly higher, and towards ITP and CTP an activity slightly lower than that with ATP. ADP was split about half as fast as ATP. AMP was not accepted by the enzyme. Replacing MgCl2 by CaCl2 resulted in an ATPase activity of 92% of that with MgCl2. Using calcium- and magnesium-ATP as substrates, apparent Km values of 0.22 and 0.33 mM, respectively, were obtained. The gel electrophoresis revealed the enrichment of a protein with an apparent Mr of 95000 and also that of microvillus actin.
...
PMID:Partial purification and characterization of rabbit-kidney brush-border (Ca2+ or Mg2+)-dependent adenosine triphosphatase. 614 3

We have determined the absolute phosphate content of microtubule-associated proteins (MAPs) and established that phosphorylation inhibits the actin filament cross-linking activity of MAPs and both of the major MAP components, MAP-2 and tau. Similar results were obtained with actin from rabbit muscle, hog brain, and Acanthamoeba castellanii. We used the endogenous phosphatases and kinases in hog brain microtubule protein to modulate MAP phosphate level before isolating heat-stable MAPs. MAPs isolated directly from twice-cycled microtubule protein contain 7.1 +/- 0.1 (S.E.) mol of phosphate/300,000 g protein. After incubating microtubule protein without ATP, MAPs, had 4.9 +/- 0.6 phosphates. After incubating microtubule protein with 1 mM ATP and 5 microM cAMP in 2 mM EGTA, MAPs had 8.6 +/- 0.5 phosphates but there was also exchange of three more [32P]phosphates from gamma-labeled ATP for preexisting MAP phosphate. Incubation of microtubule protein with ATP and cAMP in 5 mM CaCl2 resulted in exchange but no net addition of phosphate to MAPs. We fractionated the MAP preparations by gel filtration and obtained MAP-2 with 4.3 to 7.5 and tau with 1.5 to 2.2 mol of phosphate/mol of protein depending on how we treated the microtubule protein prior to MAP isolation. The actin filament cross-linking activity of whole MAPs, MAP-2, and tau depended on the MAP-phosphate content. In all cases, phosphorylation of MAPs inhibited actin filament cross-linking activity. The concentration of high phosphate MAPs required to form a high viscosity solution with actin filaments was 2 to 4 times more than that of low phosphate. MAPs. During incubation of microtubule protein with [gamma-32P]ATP, only MAP peptides are labeled. Treatment of these MAPs with either acid or alkaline phosphatase removes phosphate mainly from MAP-2, with an increase in actin filament cross-linking activity. Thus, both MAP phosphorylation and the effect of phosphorylation on actin cross-linking activity of MAPs are reversible.
...
PMID:Phosphorylation of microtubule-associated proteins regulates their interaction with actin filaments. 630 75

Acid phosphatase activity was studied biochemically in homogenates of secretory enamel organs from the rat. Incubations with crude homogenate failed to show distinct pH optima or kinetics characteristic for single enzymes. Crude homogenate activity was strongly inhibited by concentrations higher than 1 mM of NaF and Na-tartrate, and higher than 10 mM of ZnSO4 and para-bromotetramisole oxalate. 10 mM MgCl2 gave a slight stimulation. CaCl2, KCl and EDTA were uneffective. Electrophoretic separation of the crude homogenate acid phosphatase on Triton X-100 containing polyacrylamide gel demonstrated the presence of at least three multiple forms of the enzyme. Two of them showed distinct pH optima at pH 4.4. The third one showed a broad pH plateau in the acid pH range. Kinetic studies of the three forms indicated single enzyme reactions. Two forms had electrophoretic mobilities similar to alkaline phosphatase. One form could be solubilized only after Triton X-100 treatment. All forms were strongly sensitive to 10 mM NaF when added to the reaction mixture. The sensibility to 10 mM ZnSO4, CuSO4, Na-tartrate and para-bromotetramisole oxalate differed between the different forms.
...
PMID:Multiple forms of acid phosphatase in rat secretory enamel organ. 695 66

A Golgi-rich fraction has been isolated from rat ascites hepatoma AH-130 cells. Unlike the usual procedure for isolating Golgi complexes from liver and other tissues, a hypotonic solution including 2 mM CaCl2 was used as the homogenization medium for the ascites hepatoma cells, followed by a combination of differential and discontinuous sucrose gradient centrifugations. Electron microscopic observation revealed that the isolated fraction consisted of cisternae, vesicles and tubular elements which were similar to those structures described previously for the Golgi fraction isolated from rat liver. Galactosyl- and sialyl-transferases were concentrated about 55- and 75-fold, respectively, in this fraction compared with the homogenate, indicating that these enzymes are useful markers for the Golgi complex of rat ascites hepatoma AH-130 cells, as they are for those of other normal tissues. The preparation was virtually free of cytochrome oxidase, but contained minor amounts of acid phosphatase, alkaline phosphatase and phosphodiesterase I activities. Electrophoretic analysis on sodium dodecylsulfate-polyacrylamide gels showed that the hepatoma Golgi membranes were resolved into at least 23 protein bands, which were apparently different from the electrophoretic profile of the plasma membrane isolated from the same hepatoma cells.
...
PMID:Isolation and characterization of the Golgi complex from rat ascites hepatoma AH-130 cells. 714 13

In rat jejunal brush-border membranes (BBM), ATP hydrolysis activity was specifically stimulated by CaCl2 and by MgCl2, allowing to identify Ca(2+)-ATPase and Mg(2+)-ATPase activities with a broad pH optimum near 8.0. Nonspecific ATPase activity (in the absence of cations) had a pH optimum above 9.5 as alkaline phosphatase. The effects of Ca2+ and Mg2+ concentrations on ATPase activity evidenced two apparent KA for each cation. At high concentrations, a similar affinity for both cations was recorded (KA: 0.35 mM). At low concentrations, the affinity for Mg2+ was greater than for Ca2+ (KA: 0.02 mM and 0.07 mM respectively). In an attempt to differentially solubilize alkaline phosphatase and ATPase activities, eleven different detergents were assayed. They more or less successfully released Ca(2+)-ATPase and Mg(2+)-ATPase activities from BBM but the more membranes were solubilized by a detergent, the more activities were lost, suggesting a close dependence on integration in BBM. As to alkaline phosphatase and nonspecific ATPase, they almost co-solubilized with Ca(2+)-ATPase and Mg(2+)-ATPase but their total activity was little affected. After treatment of BBM with phosphatidylinositol-specific phospholipase C (E.C. 3.1.4.10), 58% of alkaline phosphatase activity and 45% of nonspecific ATPase activity were released in the supernatant while Ca(2+)-ATPase and Mg(2+)-ATPase activities remained totally incorporated in BBM pellets. These last results definitively demonstrate that Ca(2+)-ATPase and Mg(2+)-ATPase activities are not manifestations of alkaline phosphatase, as earlier suggested, but rather result from the existence of one or several intrinsic membrane enzymes.
...
PMID:Ca(2+)-ATPase and Mg(2+)-ATPase activities distinct from alkaline phosphatase in rat jejunal brush-border membranes. 751 33

A 72-year-old woman was referred to hospital for obnubilation with general muscle weakness and hypotonia. Biology showed hypocalcemia, hypophosphatemia, increased serum creatine kinase and alkaline phosphatase levels. Brain CT scan, cerebrospinal fluid examination, and electromyogram were normal. Clinical status and electroencephalogram were consistent with non-convulsive generalized status epilepticus. The treatment included clonazepam and CaCl2 and consciousness returned to normal. A treatment with multivitamin infusion containing vitamin D2 was given for 3 weeks. Muscle weakness improved partially. Serum vitamin D3 level was low and osteomalacic myopathy was diagnosed. A treatment was given with 25OH vitamin D3, 50 micrograms per day. Two months later, serum vitamin D3 and creatine kinase levels were normal and the patient could walk without help. We conclude that vitamin D status should be monitored in elderly patients with muscle symptoms and abnormal calcium status. Osteomalacic myopathy should be considered in critically ill patients with muscle symptoms of an unclear cause.
...
PMID:Muscle weakness in intensive care patients: initial manifestation of vitamin D deficiency. 770 75

The effects of cisplatin (CDDP), a potent anti-cancer agent, and its various analogues were analyzed for any biochemical changes involving Ca2+ and lysosomal and membrane-associated transport enzymes in rat kidney, liver, serum, urine, tissue homogenates, and isolated mitochondria. Correlation was made with any morphological changes observed by light and electron microscopy to gain an insight into the mechanism of action of various platinum coordination complexes. CDDP in its hydrolyzed state under conditions of low chloride ion concentrations causes uncoupling of oxidative phosphorylation, calcium efflux from the mitochondria, inhibits ATP synthesis, lowers membrane-associated calcium and various membrane transport enzymes, and induces an increase in the number of lysosomes. Enzymes such as alkaline phosphatase are stripped from the brush borders of the proximal tubule cells and are discharged in the urine. However, daily IV injections of calcium (1.1 ml of 1.3% CaCl2) supplementation protect the membrane-associated enzymes from cisplatin action. Carboplatin (CBDCA), an analogue of CDDP and the least nephrotoxic of all its analogues, shows little effect on the membrane-associated transport enzymes. Therefore, cisplatin and its various analogues seem to affect the membrane transport enzymes to varying degrees with related nephrotoxicity. Calcium supplementation seems to protect these enzymes and preserve kidney function.
...
PMID:A histochemical approach to the mechanism of action of cisplatin and its analogues. 851 48


<< Previous 1 2 3 4 Next >>

---