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

A peptide containing the four closely grouped phosphoseryl residues present in beta-casein has been enzymatically dephosphorylated with bovine spleen phosphoprotein phosphatase (EC 3.1.3.16). The course of the dephosphorylation reaction has been followed by cellulose acetate electrophoresis and the amount of partially phosphorylated peptides present at each stage quantified by the same method. The phosphate groups are shown to be removed in a sequential manner and the rate constants for each stage of the dephosphorylation have been computed from the data obtained. The rate constants indicate that interaction in the intact peptide results in an enhancement of the activity of the phosphoseryl cluster.
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PMID:A kinetic analysis of the dephosphorylation, by bovine spleen phosphoprotein phosphatase (EC 3.1.3.16) of a phosphopeptide derived from beta-casein. 18 Oct 85

1. Various proteins isolated from bovine tracheal smooth muscle were examined as phosphate acceptor substrates for a cyclic AMP-dependent protein kinase isolated from the same tissue. A fraction prepared in a manner similar to that of skeletal muscle troponin was the best substrate of the presumptive contractile proteins isolate. Actomyosin and tropomyosin were relatively poor substrates. 2. An assay was developed for the rapid detection in a large number of samples of the muscle specific substrate for the protein kinase on which we reported previously. 3. Using this assay, the muscle specific substrate found in bovine tracheal smooth muscle was partially purified resulting in a preparation which when resolved by polyacrylamide gel electrophoresis showed a single peak of 32P incorporated, and which could be further characterized. 4. Our findings suggest that the substrate contains a protein subunit of molecular weight 19 000, which can be phosphorylated at serine and threonine residues, in the presence of cyclic AMP and protein kinase. The phosphate is in a covalent ester linkage with these residues. 5. A phosphoprotein phosphatase was isolated from the bovine tracheal smooth muscle. 6. Bovine tracheal smooth muscle contains cyclic AMP dependent protein kinase and phosphoprotein phospahatase activity as well as the muscle specific substrate, suggesting that these elements may be part of a mechanism which regulates smooth muscle tone.
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PMID:Cyclic AMP-stimulated phosphorylation of bovine tracheal smooth muscle contractile and non-contractile proteins. 18 31

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 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 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 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

In the preceding paper (Sheetz, M. and S.J. Singer. 1977. J Cell Biol. 73:638-646) it was shown that erythrocyte ghosts undergo pronounced shape changes in the presence of mg-ATP. The biochemical effects of the action of ATP are herein examined. The biochemical effects of the action of ATP are herein examined. Phosphorylation by ATP of spectrin component 2 of the erythrocyte membrane is known to occur. We have shown that it is only membrane protein that is significantly phosphorylated under the conditions where the shape changes are produced. The extent of this phosphorylation rises with increasing ATP concentration, reaching nearly 1 mol phosphoryle group per mole of component 2 at 8mM ATP. Most of this phosphorylation appears to occur at a single site on the protein molecule, according to cyanogen bromide peptide cleavage experiments. The degree of phosphorylation of component 2 is apparently also regulated by a membrane-bound protein phosphatase. This activity can be demonstrated in erythrocyte ghosts prepared from intact cells prelabeled with [(32)P]phosphate. In addition to the phosphorylation of component 2, some phosphorylation of lipids, mainly of phosphatidylinositol, is also known to occur. The ghost shape changes are, however, shown to be correlated with the degree of phosphorylation of component 2. In such experiment, the incorporation of exogenous phosphatases into ghosts reversed the shape changes produced by ATP, or by the membrane-intercalating drug chlorpromazine. The results obtained in this and the preceding paper are consistent with the proposal that the erythrocyte membrane possesses kinase and phosphates activities which produce phosphorylation and dephosphorylation of a specific site on spectrin component 2 molecules; the steady-state level of this phosphorylation regulates the structural state of the spectrin complex on the cytoplasmic surface of the membrane, which in turn exerts an important control on the shape of the cell.
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PMID:On the mechanism of ATP-induced shape changes in human erythrocyte membranes. II. The role of ATP. 19 4

The activity of two purified homogeneous phosphoprotein phosphatases types P I and P II) (phosphoprotein phosphohydrolase, EC 3.1.3.16) from rabbit liver (Khandelwal, R.L., Vandenheede, J.R., and Krebs, E.G. (1976) J. Biol. Chem. 251, 4850-4858) were examined in the presence of divalent cations, Pi, PPi, nucleotides, glycolytic intermediates and a number of other compounds using phosphorylase a, glycogen synthase D and phosphorylated histone as substrates. Enzyme activities were usually inhibited by divalent cations with all substrates; the inhibition being more pronounced with phosphorylase a. Zn2+ was the most potent inhibitor among the divalent cations tested. The enzyme was competitively inhibited by PPi (Ki = 0.1 mM for P I and 0.3 mM for PII), Pi (Ki = 15 mM for P I and 19.8 mM for P II) and p-nitrophenyl phosphate (Ki = 1 mM and 1.4 mM for P I and P II, respectively) employing phosphorylase a as the substrate. The compounds along with a number of others (Na2SO4, citrate, NaF and EDTA) also inhibited the enzyme activity with the other two substrates. Severe inhibition of the enzyme was also observed in the presence of the adenine and uridine nucleotides; monophosphate nucleotides being more inhibitory with phosphorylase a, whereas the di- and triphosphate nucleotides showed more inhibition with glycogen synthase D and phosphorylated histone. Cyclic AMP had no significant effect on enzyme activity with all the substrates tested. Phosphorylated metabolites did not show any marked effect on the enzyme activity with phosphorylase a as the substrate.
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PMID:Some properties of purified phosphoprotein phosphatases from rabbit liver. 20 Feb 72

1. Calcium transport into microsomal vesicles of respiratory (tracheal) smooth muscle was characterized. This calcium transport was ATP dependent and stimulated by the presence of the oxalate ion. The magnitude of transport was similar to that reported for microsomes from other types of smooth muscle. 2. Bovine and rabbit, heavy and light microsomes were isolated from respiratory (tracheal) and vascular (aortic) smooth muscle. Preincubation of these vesicles with cyclic AMP and protein kinase did not alter the transport of calcium into the vesicles. There uas no evidence of phosphate incorporation into microsomal membrane proteins. Similar results were obtained if phosphorylase b kinase replaced the combination of cyclic AMP and protein kinase during the preincubation. 3. The phosphoprotein phosphatase activity of cardiac sarcoplasmic reticulum and smooth muscle microsomes was determined. The activity of this enzyme was found to be several-fold less in the cardiac sarcoplasmic reticulum than in various smooth muscle microsome preparations.
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PMID:Determination of calcium transport and phosphoprotein phosphatase activity in microsomes from respiratory and vascular smooth muscle. 20 Dec 93

A phosphoprotein phosphatase (phosphoprotein phosphohydrolase, EC 3.1.3.16) was partially purified from pig heart using as substrate H2B histone which had been phosphorylated at Ser-32 and Ser-36 by adenosine 3',5'-monophosphate-dependent protein kinase (EC 2.7.1.37). The enzyme had a molecular weight of approx. 250 000 and was converted to a smaller form with a molecular weight of approx. 30 000 upon treatment with ethanol. Phosphorylase alpha (EC 2.4.1.1) and phosphorylated H1 histone also served as substrates for both forms of the enzyme. The conversion of the large form of the enzyme to the small form decreased the phosphohistone phosphatase activity to 25-50% with a concomitant 7-fold increase in the phosphorylase alpha phosphatase activity. Ser-36 phosphate was removed 6- and 15-fold more rapidly than was Ser-32 phosphate by the large and small forms of the enzyme, respectively. Among Ser-36-containing tryptic phosphopeptides derived from phosphorylated H2B histone, Lys-Glu-Ser(P)-Tyr-Ser-Val-Tyr was the shortest phosphopeptide which was dephosphorylated at a significant reaction rate with the phosphoprotein phosphatase. The Km values for phosphorylated H2B histone and the tryptic phosphopeptide were 23.7 micron and 187.1 micron, respectively, with the large form, and 81.4 micron and 90.0 micron, respectively, with the small form of the enzyme.
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PMID:Comparison of two forms of pig heart phosphoprotein phosphatase. 20 53


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