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)

Adults rats receive by gavage 10 mM CaCl2 [+45Ca] solution containing or not 100 mM glucid, 10-100 mM EDTA or these both compounds. Calcium transfer is determined by the evaluation of [45Ca] in intestine and feces as well as in plasma and femur. Basic Ca++ transfer which corresponds to the CaCl2 solution was doubled in the presence of glucids. EDTA addition abolishes completely the glucid effect, exercising any influence on basic CA++ transfer. Injected into ligaturated ileal loop, the glucid gives the same effect. But the addition of phosphate not only removed glucid action but also inhibits the basic Ca++ transfer. The glucids, known acceptors of phosphate, increase Ca transfer. EDTA and phosphate, alkaline phosphatase inhibitors, exhibit an opposite effect. Phlorizin, as it was seen previously, acts exactly as EDTA. All these facts question: the simultaneous transfer of Ca and glucid, the possibility of a glucid phosphorylation, the part in these events of alkaline phosphatase, phosphorylating, phosphatasic and phosphorylable microvillar protein.
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PMID:[Effects of alkaline phosphatase inhibitors on intestinal transfer of calcium]. 313 25

A small fraction of polyoma virus middle-sized tumor (T) antigen is phosphorylated in vivo, resulting in a small amount of phosphotyrosine and phosphothreonine and significantly larger amounts of phosphoserine. When infected cells are separated into nuclear, plasma membrane, and low-speed supernatant fractions, 80-95% of in vivo-phosphorylated middle-sized T antigen is localized to the plasma membrane fraction, while 25-50% of [35S]methionine-labeled middle-sized T antigen is found in the nuclear fraction and the same amount is found in the plasma membrane fraction. Immunoprecipitated T antigens contain a protein kinase activity that phosphorylates middle-sized T antigen at tyrosine residues. Eighty to 90% of this activity is located in the plasma membrane fraction. When immunoprecipitated T antigens are treated with alkaline phosphatase, middle-sized T antigen-phosphorylating activity decreases as 32PO4 is lost from in vivo 32P-labeled middle-sized T antigen. The possibility that in vivo-phosphorylated middle-sized T antigen located in the plasma membrane is an active tyrosine-specific kinase is discussed.
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PMID:Differential subcellular localization of in vivo-phosphorylated and nonphosphorylated middle-sized tumor antigen of polyoma virus and its relationship to middle-sized tumor antigen phosphorylating activity in vitro. 629 53

In solubilized, (wheat germ) lectin-purified preparations of rat liver membranes, insulin stimulated the incorporation of 32P from [gamma-32P]ATP into tyrosine residues of insulin receptor, casein, and histones. Despite the presence of both protein kinase and phosphatase activities in these preparations, no decrease in the 32P content of receptors (preincubated with or without insulin (0.5-100 nM)) was detected whether 32P incorporation was terminated by excess ATP, ATP + Mn2+, EDTA, or phosphatase inhibitors. Similarly, there was no decrease in the 32P content of phosphoreceptors incubated for up to 60 min with fresh receptor preparations in the presence or absence of insulin. Dephosphorylation of the insulin receptor to 20% of original 32P content only occurred when alkaline phosphatase was added to the preparations. It is concluded that endogenous receptor phosphatase(s) are either missing or inactive in these preparations, and consequently, insulin stimulates phosphorylation of its own receptor by activating a protein kinase. The kinase activity is tightly associated with the receptor itself; insulin also stimulated the phosphorylation of both receptor subunits in purified insulin-receptor complexes that had been immunoprecipitated by anti-insulin antibodies. However, the phosphorylating machinery is much more sensitive to heat inactivation than the binding function (90% less 32P incorporation versus 15% less binding during 60-min incubation at 37 degrees C), suggesting that the kinase is not associated exclusively with the insulin-binding domain.
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PMID:Insulin stimulated phosphorylation of its own receptor. Activation of a tyrosine-specific protein kinase that is tightly associated with the receptor. 633 86

Incubation of S49 cell membranes at 0 degree C resulted in a loss of adenylate cyclase activity, but addition of ATP and ATP regenerating system prevented the decrease of the activity. A non-phosphorylating analogue of ATP, adenyl-5'-yl imidodiphosphate, was less effective than ATP. Treatment of solubilized adenylate cyclase with calf intestine alkaline phosphatase caused the decrease of the activity. Membranes from cyc- S49 mutant cells, which are devoid of guanine nucleotide-binding protein, yielded the same results as membranes from S49 cells, indicating that the catalytic component is involved in the alteration of the enzyme activity by these treatments. These results suggest that phosphorylation and dephosphorylation of the catalytic component may regulate adenylate cyclase activity.
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PMID:Alteration of adenylate cyclase activity by phosphorylation and dephosphorylation. 683 11

1,25-Dihydroxycholecalciferol increases the incorporation of leucine into a protein component (Mr = 84000) of the chick intestinal brush-border membrane. Evidence has now been obtained showing this protein to be sub-unit of alkaline phosphatase. Pure chick intestinal alkaline phosphatase was prepared and antibodies raised against it in rabbits. This enzyme and the brush-border protein behaved identically on gel electrophoresis, and in terms of their phosphorylating activity and enzyme activity whether as the enzymically active dimeric form or when reduced to the sub-unit form. The anti-(alkaline phosphatase) reacted with the protein into which the incorporation of leucine was stimulated by 1,25-dihydroxycholecalciferol.
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PMID:Incorporation of labelled leucine into alkaline phosphatase in response to 1,25-dihydroxycholecalciferol in chick intestinal brush borders. 689 55

A new sensing principle of enzyme activation is demonstrated for the determination of glycogen phosphorylase b and its allosteric effector AMP. As the indicator of the phosphorylase catalysed glycogen phosphorolysis, glucose-1-phosphate formation has been detected with an enzyme sequence comprising coentrapped alkaline phosphatase, mutarotase and glucose oxidase on a hydrogen peroxide indicating electrode. The optimized three-enzyme sensor was useful for the determination of 0.005-0.2 U.ml-1 glycogen phosphorylase a and b. A biosensor for AMP and inorganic phosphate has been developed by coupling glycogen entrapped phosphorylases to the three-enzyme indicator membrane. The measurement of AMP is based on the modulation of the phosphorylase b catalysed glycogen phosphorylating activity. The proposed sensor responds to AMP between 5 and 150 microM. The calibration graph of the reagentless phosphate sensor is linear between 0.05 and 1 mM.
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PMID:Enzyme activation for activator and enzyme activity measurement. 825 Nov 31

gamma-Aminobutyric acidA (GABAA) receptors are linked to ion channels which mediate many aspects of neural inhibition. Although the effects of phosphorylation on GABAA receptor function have been widely studied, the actual role of phosphorylation in the regulation of these receptors still remains controversial. In recent reports, we have described the effects of phosphorylating/dephosphorylating enzymes on the regulation of GABAA receptors in a rat cortical slice preparation (Shaw et al., Mol. Neuropharmacol., 2 (1992) 297-302; Shaw and Lanius, Dev. Brain Res., 70 (1992) 153-161; Pasqualotto et al., Neuroreport, 4 (1993) 447-450) and predicted that ionic co-factors are involved in mediating the regulation of GABAA receptors by kinases and phosphatases. In the present report, the effects of chloride, sodium, potassium, and calcium were examined alone and in the presence of cAMP-dependent protein kinase (protein kinase A) or alkaline phosphatase. The results showed a decrease in [3H]SR 95531 (GABAA receptor antagonist) binding after incubation with chloride alone; this decrease was further enhanced in the presence of protein kinase A. Both effects could be blocked by a protein kinase A inhibitor. Conversely, an increase in [3H]SR 95531 binding was observed after incubation with sodium alone; this increase was further enhanced in the presence of alkaline phosphatase. In both cases these increases in binding could be blocked by sodium orthovanadate, a phosphatase inhibitor. Potassium was ineffective under all conditions; calcium showed enzyme-independent effects at low concentrations only. These results suggest the existence of a novel chloride-dependent protein kinase which may have significant sequence homology to protein kinase A, and a novel sodium-dependent phosphatase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:gamma-Aminobutyric acidA receptor regulation by a chloride-dependent kinase and a sodium-dependent phosphatase. 830 57

Mitotic division in yeast requires the activity of topoisomerase II, a DNA topology modifying enzyme that is able to disentangle sister chromatids after DNA replication. Previous work has shown that topoisomerase II is a phosphoprotein in intact yeast cells. We show here that when dephosphorylated in vitro, topoisomerase II is unable to cleave or decatenate kinetoplast DNA. An efficient kinase activity that modifies topoisomerase II on seven major sites was found to copurify with the enzyme purified from yeast. Characterization of this kinase, analysis of phosphotryptic peptides, and studies with a yeast mutant deficient in casein kinase II, indicate that the copurifying kinase is casein kinase II (CKII). Topoisomerase II itself has no self-phosphorylating activity. Modification of topoisomerase II by the copurifying kinase is sufficient to restore decatenation activity after dephosphorylation by alkaline phosphatase. The CKII target sites have been mapped to multiple serine and threonine residues on 4 tryptic fragments within the C-terminal 350 amino acids of yeast topoisomerase II. These results are consistent with a model in which the C-terminal domain of topoisomerase II is a negative regulatory domain that is neutralized by phosphorylation.
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PMID:Casein kinase II copurifies with yeast DNA topoisomerase II and re-activates the dephosphorylated enzyme. 838 77

In mammalian cells DNA synthesis is more complicated than in prokaryotes and less well understood. Here we incubated intact mammalian cells (polyamine auxotrophic Chinese hamster ovary cells and primary human fibroblasts) with [32P]orthophosphate and found that, besides high molecular weight DNA, a species of low molecular weight DNA, approximately 450 bp in size, became efficiently labeled. The short DNA was labeled first, and in pulse-chase experiments the labeling was transient. The isolated small DNA fragments (RNase A-treated) were phosphorylated by T4 polynucleotide kinase specific for polynucleotides with 5'-OH ends. A polynucleotide kinase phosphorylating these DNA pieces was also detected in nuclear extracts of the cells. Treatment with alkaline phosphatase removed most of the 32P label incorporated into the small DNA in vivo. Labeling with deoxyribonucleosides did not reveal these fragments. We hypothesize that the low molecular weight DNA represents Okazaki fragments and that the mammalian DNA replication machinery includes a polynucleotide kinase phosphorylating the 5'-termini of Okazaki fragments. This would imply a novel step in DNA synthesis. We also show that depriving cells of polyamines reversibly blocks synthesis of high molecular weight DNA and leads to accumulation of the short DNA pieces, suggesting a role for polyamines in joining the Okazaki fragments.
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PMID:Phosphorylation of Okazaki-like DNA fragments in mammalian cells and role of polyamines in the processing of this DNA. 860 90

The M-1 cell line is derived from the mouse cortical collecting duct and displays the low-conductance, highly Na(+)-selective channel activity of the alpha,beta, gamma-heterotrimeric epithelial Na+ channel (ENaC). The short-circuit current (Isc) across M-1 monolayers was 89 +/- 4 microA/cm2, and the transepithelial conductance was 2.1 +/- 0.2 mS/cm2. Isc was abolished by blocking the Na+ pump with ouabain. Both Isc and transepithelial conductance (gT) were inhibited by benzamil > amiloride >> dimethylamiloride. Under our experimental conditions, vasopressin, vasopressin, forskolin, and dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP) had no detectable effects on Isc or gT. Increasing apical Na+ entry with nystatin increased Isc. The possible regulation of the M-1 Na+ channel by cAMP-activated protein kinase A (PKA) was further examined with excised inside-out patches. The open-time probability (Po) was not fixed, displaying substantial variance. Perfusion with ATP itself, with the catalytic subunit of PKA with ATP, or with alkaline phosphatase had no consistent effect on Po, the unitary current, or the kinetics of the M-1 Na+ channel. The data are consistent with the concept that PKA stimulates ENaCs by phosphorylating a site with access to but not within the apical membrane patch during cell-attached and excised-patch studies.
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PMID:Regulation of epithelial Na+ channels from M-1 cortical collecting duct cells. 889 16


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