Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Suspensions of renal cortical tubules were incubated with 33Pi and exposed to parathyroid hormone (40 mlg/ml) or 1 mM dibutyryl cyclic AMP. In other experiments homogenates of renal cortex were assayed for protein kinase and phosphoprotein phosphatase activity using [gamma-32P]ATP with or without 5 mM cyclic AMP. Proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and phosphorylation of proteins measured by liquid scintillation counting of gel slices. The pattern of protein phosphorylation was similar in control tissue from both tubule suspensions and homogenates. In intact tubules, parathyroid hormone stimulated the phosphorylation of four proteins with molecular weights of approx. 150 000, 125 000, 100 000 and 50 000 by 28%, 24%, 13%, and 20%, respectively. Results with dibutyryl cyclic AMP were comparable but more variable. Stimulation of phosphorylation by cyclic AMP in homogenates was more generalized with the major effect on a 50 000 dalton protein (50% stimulation). No effect of cyclic AMP on dephosphorylation of proteins was observed. The results are interpreted as indicating that increased phosphorylation of cell proteins is part of the cyclic AMP-mediated response of the renal cortex to parathyroid hormone.
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PMID:Effect of parathyroid hormone and cyclic AMP on protein phosphorylation in rabbit kidney cortex. 18 25

beta-Casein, and the phosphate containing peptide derived from it by tryptic digestion, have been dephosphorylated by the action of two phosphatases. Escherichia coli alkaline phosphatase (EC 3.1.3.1) has been shown to remove the phosphates from these substrates in two distinct stages. Substrate molecules retaining three of the original phosphoseryl residues accumulate during the reaction and are resistant to further dephosphorylation at low enzyme concentrations. In contrast bovine spleen phosphoprotein phosphatase (EC 3.1.3.16) achieves complete dephosphorylation of these substrates sequentially without any of the intervening species showing resistance to the action of the enzyme. The phosphopeptide has been partially dephosphorylated by the action of the two phosphatases and the resultant peptides containing three phosphoseryl residues compared in their reactivity toward the E. coli alkaline phosphatase. The results obtained are discussed in relation to the mode of action of the two enzymes.
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PMID:A study of the enzymic dephosphorylation of beta-casein and a derived phosphopeptide. 18 32

The phosphorylation and dephosphorylation reactions of the proteins of isolated rat liver nuclei were examined in the presence of ATP. It was shown that the plateau value of the phosphorus incorporation at high concentrations of ATP is the result of an equilibrium of phosphorylation and dephosphorylation. The data of 32P-labelling experiments and those of chemical determination of net change of phosphorus content were compared. The activity of an efficient protein phosphatase in rat liver nuclei is demonstrated. It was shown that the pool of protein-phosphorus in the nuclei is heterogeneous as regards its turnover rate. A protein-phosphorus fraction of high turnover dominates the picture of phosphorylation and dephosphorylation reactions when studied with [gamma-32P] ATP in vitro.
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PMID:Some characteristics of phosphorylation and dephosphorylation of proteins of isolated rat liver nuclei. 18 93

Two heat-stable and trypsin-labile inhibitors of phosphorylase phosphatase, designated inhibitor-1 and inhibitor-2, were partially purified from extracts of rabbit skeletal muscle by heating and coloumn chromatography using DEAE-dellulose and Bio-gel P-60. Inhibitor-1 exists in an active phosphorylated form and an inactive dephosphorylated form. The interconversion of phosphorylated inhibitor-1 and dephosphorylated inhibitor-1 is mediated by protein kinase dependent on adenosine 3':5'-monophosphate (cyclic AMP) and a Mn2+-stimulated phosphoprotein phosphatase. Inhibitory activity of inhibitor-2 is not influenced by treatment with either the kinase or the Mn2+-stimulated phosphatase. The molecular weights of inhibitor-1 and inhibitor-2 estimated by sodium dodecylsulfate-polyacrylamide gel electrophoresis are 26000 and 33000 respectively. Both inhibitor-1 and inhibitor-2 inhibit phosphorylase phosphatase by a mechanism which appears to be non-competitive with respect to the substrate phosphorylase a. Inhibitor fractions at early stages of purification also inhibit cyclic-AMP-dependent histone phosphorylation, but this kinase inhibitory activity resides with a protein moiety which is separable from inhibitor-1 and inhibitor-2.
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PMID:Separation and characterization of two phosphorylase phosphatase inhibitors from rabbit skeletal muscle. 18 46

The phosphoprotein phosphatase (PPPase) activity that is found associated with oestrogen-induced protein(s) is not itself induced by oestrogen. Indeed, this activity was found at the same electrophoretic position (i.e. the position of the oestrogen-induced protein) and in equal amounts relative to the total PPPase activity, whether the cytosol fraction from control or from stimulated uteri was tested.
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PMID:Oestrogen-induced uterine protein: presence of associated phosphoprotein phosphatase activity before oestrogen treatment. 18 66

The D to I conversion of glycogen synthase from human polymorphonuclear leukocytes was examined both in a gel-filtered homogenate and in a preparation of glycogen particles with adhering enzymes, purified by chromatography on concanavalin A bound to Sepharose. It was found that glucose 6-phosphate as well as mannose 6-phosphate, glucosamine 6-phosphate, and 2-deoxy-glucose 6-phosphate activated the reaction, whereas the corresponding sugars were without effect. Mn2+ and Ca2+ increased the conversion rate by 51% and 27%, respectively, whereas Mg2+ and inorganic phosphate were without effect. Sodium fluoride inhibited the reaction completely. Glycogen inhibited the reaction in physiological concentrations and 0.5 mM glucose 6-phosphate was able to overcome this inhibition. MgATP greatly augmented the inhibition caused by glycogen in the glycogen particle preparation. This combined effect could be overcome by glucose 6-phosphate in concentrations from 0.1 to 1 mM. Phosphorylase alpha purified from human polymorphonuclear leukocytes inhibited the D to I conversion in a glycogen particle preparation. The inhibition was counteracted by glucose 6-phosphate and to a lesser degree by AMP. Phosphorylase beta was also inhibitory, but only at higher concentrations than phosphorylase alpha. No phosphorylase phosphatase activity was found in the glycogen particle preparation, which may indicate that chromatography on concanavalin A-Sepharose separates this enzyme from the synthase phosphatase or partially destroys the activity of a hypothetical common protein phosphatase.
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PMID:Effect of metabolites and phosphorylase on the D to I conversion of glycogen synthase from human polymorphonuclear leukocytes. 18 43

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.
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PMID:Purification and control of bovine adrenal cortical cholesterol ester hydrolase and evidence for the activation of the enzyme by a phosphorylation. 18 99

A phosphoprotein phosphatase (phosphoprotein phosphohydrolase, EC 3.1.3.16) has been partially purified from rat liver homogenates by (NH4)2SO4 and ethanol precipitations followed by DEAE-cellulose and Sepharose 6B chromatography. The phosphoprotein phosphatase is capable of cleaving [32P]phosphate from radiolabelled phosphopyruvate kinase (type L) (EC 2.7.1.40), phosphohistones, and phosphoprotamine. However, it did not detectably dephosphorylate ATP, ADP, DL-phosphorylserine or beta-glycerophosphate. Dephosphorylation of [32P]phosphopyruvate kinase was stimulated by divalent cations and inhibited by ATP, ADP, Fru-1,6-P2, and orthophosphate. Divalene cations could reverse inhibition induced by ADP or ATP. At least one function of the phosphoprotein phosphatase may be to remove phosphate groups from the phosphorylated form of pyruvate kinase in the liver.
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PMID:Purification and properties of a phosphoprotein phosphatase from rat liver. 19 Oct 81

Phosphoprotein phosphatase [phosphoprotein phosphohydrolase EC 3.1.3.16] in the soluble fraction of rabbit skeletal muscle, when assayed with phosphorylase a[EC 2.4.1.1] from rabbit skeletal muscle and phosphohistone as substrates, was resolved into three active fractions (Fractions I, II, and III in order of elution) by DEAE-cellulose column chromatography. Sucrose density gradient centrifugation showed that these fractions were composed of subfractions of different molecular size (I: 7.3S and 4S; II: 8S and 4S; III; 6.7S). Components with larger molecular size in the major fractions, II and III, were dissociated to a molecular size similar to that of the smallest component on freezing in the presence of mercaptoethanol. These results indicate that phosphoprotein phosphatase from skeletal muscle occurs in multiple forms very similar to those of the liver enzyme reported previously (Kobayashi, Kato and Sato (1975) Biochim. Biophys. Acta. 373, 343-355).
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PMID:Multiple molecular forms of phosphoprotein phosphatase. Separation of four forms of the rabbit skeletal muscle enzyme. 19 39

Phosphoprotein phosphatase activity is found in preparations of sarcoplasmic reticulum isolated from canine heart when assayed with either phosphate or phosphorylated sarcoplasmic reticulum as substrate. Phosphoprotein phosphatase-catalyzed dephosphorylation of the 22,000 dalton phosphoprotein of cardiac sarcoplasmic reticulum is stimulated markedly by MnCl2 (5 mM) and to a lesser extent by MgCl2 (5 mM); inorganic phosphate (50 mM) and NaF (25 mM) are inhibitory. Dephosphorylation of this 22,000 dalton phosphoprotein is correlated with a decreased initial rate of calcium transport. The close structural and functional relationship of phosphoprotein phosphatase to the cardiac sarcoplasmic reticulum suggests a possible role of this enzyme in reversing the relaxation-promoting effects of catecholamines on the intact heart.
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PMID:Decrease in calcium transport associated with phosphoprotein phosphatase-catalyzed dephosphorylation of cardiac sarcoplasmic reticulum. 19 77


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