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:3.1.3.16 (calcineurin)
17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
...
PMID:Comparison of two forms of pig heart phosphoprotein phosphatase. 20 53

Polyamine hydrochlorides, NaCl and magnesium acetate stimulated the enzymatic dephosphorylation of phosphorylated H2B histone by two forms (large form, mol. wt. 250 000; small form, mol. wt. 30 000) of a pig heart phosphoprotein phosphatase (phosphoprotein phosphohydrolase, EC 3.1.3.16). These ionic compounds stimulated the large form of the enzyme 5--9-fold but stimulated the small form of theenzyme only 2-fold. With phosphorylated H2B histone as substrate, these effectors caused an increase in both Km and V values of the two forms of the enzyme. On the other hand, when a tryptic phosphodecapeptide derived from phosphorylated H2B histone was used as substrate, these effectors were always inhibitory apparently non-competitively with respect to the substrate. Using phosphorylated H1 histone as substrate, these effectors stimulated the large form of the enzyme 2-fold but inhibited the small form. With phosphorylase a as substrate, the reactions were also inhibited by these effectors irrespective of the enzyme employed. With respect to phosphorylase a, this inhibition was apparently of a competitive type for the large form and a non-competitive type for the small form of the enzyme.
...
PMID:Effects of polyamine hydrochlorides and salts on phosphoprotein phosphatase. 21 Aug 24

The phosphorylation of Ser-32, in addition to Ser-36 of H2B histone, stimulated the rate of Pi release from Ser-36 by the small form (Mr 31 000) of pig heart phosphoprotein phosphatase both in the absence and presence of 50 mM magnesium acetate. By phosphorylation at Ser-32, the Km value for Ser-36 phosphate in H2B histone was increased from 0.38 microM to 1.16 microM in the absence of magnesium acetate, but not significantly changed (from 37.4 microM to 26.2 microM) in the presence of magnesium acetate. With the large form (Mr 224000) of the phosphoprotein phosphatase, however, the phosphorylation at Ser-32 suppressed the rate of Pi release from Ser-36 both in the absence and presence of magnesium acetate. The Km value of the large form for Ser-36 phosphatase in H2B histone was nevertheless increased by phosphorylation at Ser-32, from 1.2 microM to 5.3 microM in the presence of magnesium acetate, but not changed (from 0.26 microM to 0.23 microM) in the absence of magnesium acetate.
...
PMID:The control of phosphoprotein phosphatase by the second-site phosphorylation of a substrate. Studies with H2B histone as model substrate. 22 81

A cytosolic insulin-sensitive serine kinase has been purified to apparent homogeneity in parallel from livers of control or acutely insulin-treated rats. The kinase is labile and requires rapid purification for stability. The kinase migrates as a band of apparent Mr = 90,000 on denaturing gels and elutes as a monomer on Superose 12 gel filtration. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis and renaturation, the 90-kDa band presumed to be the kinase shows kinase activity toward myelin basic protein in situ. Substrates of the kinase include Leu-Arg-Arg-Ala-Ser-Leu-Gly (Kemptide), ribosomal protein S6, S6 peptide, a proline-rich peptide substrate, microtubule-associated protein 2, and myelin basic protein. The kinase also phosphorylates histones H1 and H2B, but does not autophosphorylate to a significant stoichiometry. The activity of the kinase is inhibited by fluoride, glycerophosphate, p-nitrophenyl phosphate, p-nitrophenol, heparin, quercetin, poly-L-lysine, and potassium phosphate, but is unaffected by calcium, cAMP, spermine, protein kinase inhibitor peptide, phorbol myristate acetate, calcium plus phosphatidylserine, or vanadate. The kinase will utilize magnesium (10 mM) as well as manganese (1 mM) as a cofactor for maximal phosphotransferase activity. The kinase is not detected by immunoblotting with antibodies directed against protein kinase C or type II S6 kinase. Taken together, these properties distinguish this kinase from other insulin-sensitive kinases that have been described previously. The purified kinase from livers of insulin-treated rats shows a 5-20-fold higher specific activity compared to enzyme prepared from control rats, suggesting a covalent modification as the mechanism of activation. Incubation of purified, insulin-stimulated kinase with purified phosphatase 2A leads to deactivation of the kinase activity, and the phosphatase inhibitor nitrophenyl phosphate blocks this deactivation. The insulin-activated kinase fails to immunoblot with anti-tyrosine phosphate antibodies. Taken together, these results indicate that insulin activates this novel cytosolic protein kinase by a mechanism that causes its phosphorylation on serine or threonine residues.
...
PMID:Purification and characterization of a cytosolic insulin-stimulated serine kinase from rat liver. 153 38

Two type 2A protein phosphatases, phosphatases I (Mr = 180,000) and III (Mr = 177,000), were purified to near homogeneity from human erythrocyte cytosol. Phosphatase I was composed of alpha (34 kDa), beta (63 kDa), and delta (74 kDa) subunits in a ratio of 1:1:1. Phosphatase III comprised alpha, beta, and gamma (53 kDa) subunits in the same ratio. Heparin-Sepharose column chromatography converted most of phosphatase I and 20% of phosphatase III into alpha 1 beta 1 which were indistinguishable from phosphatase IV (Usui, H., Kinohara, N., Yoshikawa, K., Imazu, M., Imaoka, T., and Takeda, M. (1983) J. Biol. Chem. 258, 10455-10463). The catalytic subunit alpha and the beta subunit of phosphatases I, III, and IV displayed identical V8 and papain peptide maps, respectively, while the peptide maps of the alpha, beta, gamma, and delta subunits were clearly distinct. The molar ratio of phosphatases I, III, and IV in erythrocyte cytosol was estimated to be 6:1:14. Comparison of molecular activities of alpha, alpha 1 beta 1, alpha 1 beta 1 delta 1, and alpha 1 beta 1 gamma 1 revealed that beta suppressed phosphorylase and P-H2B histone phosphatase activities of alpha but stimulated the P-H1 histone phosphatase activity, and delta suppressed all the phosphatase activities of alpha 1 beta 1. The gamma subunit stimulated the P-histone phosphatase activity of alpha 1 beta 1 but inhibited the phosphorylase and P-spectrin phosphatase activities. The beta subunit increased the Mg2+ or Mn2+ requirement for P-H2B histone phosphatase activity of alpha, an effect which was counteracted by delta. The effects of heparin, H1 histone, protamine, and polylysine on the phosphorylase phosphatase activity of phosphatases I, III, IV, and alpha were described and discussed in connection with the functions of the subunits.
...
PMID:Three distinct forms of type 2A protein phosphatase in human erythrocyte cytosol. 283 Dec 1

Treatment of a pig heart phosphoprotein phosphatase (phosphoprotein phosphohydrolase, EC 3.1.3.16) of Mr 224 000 with 40% ethanol followed by gel-filtration on Sephadex G-150, dissociated the enzyme into an active component of Mr 31 000 and an inactive component of Mr 80 000. The inactive component reassociated with the active component, resulting in the formation of an enzyme form of Mr 123 000. A large excess of either component in the reassociation produced only this enzyme form. The ability of the inactive component to associate with the active component was lost by treatment of the inactive component with trypsin and heat (60 degrees C, 2 min) but not with DNAase and RNAase. Effects of the inactive component on the activities of the active component by the association were as followings. The inactive component: (1) stimulated slightly the 32P-H2B histone phosphatase activity in the presence of either NaCl or Mg(CH3COO)2 but inhibited strongly in the absence of the salts; (2) stimulated the 32P-H1 histone phosphatase activity in the presence of the salts; (3) inhibited the phosphorylase a phosphatase activity in the presence and absence of the salts; (4) enhanced the response to the stimulatory effects of the salts on the dephosphorylation of 32P-histone; and (5) protected the phosphorylase a phosphatase activity from inhibition by the salts.
...
PMID:Isolation of an inactive component from pig heart phosphoprotein phosphatase and its reassociation with an active component. 624 55

The Ca2+-dependent regulator protein (CDR), also frequently termed "calmodulin" was determined to influence the dephosphorylation of mixed calf thymus histones or purified histones 1, 2A, or 2B by a partially purified bovine brain phosphoprotein phosphatase. CDR increase the rate of dephosphorylation of mixed histones more than 20-fold. With increasing concentrations of mixed histones as substrate, a proportionate increase of CDR concentration was required to maintain maximal expression of histone phosphatase activity. Mixed histones suppressed the activation by CDR of a bovine brain cyclic nucleotide phosphodiesterase activity, with activation being restored by increased quantities of CDR. Dephosphorylation of casein and phosphorylase alpha by the phosphatase preparation was not affected by CDR. These observations support the interpretation that the effects of CDR on histone dephosphorylation are substrate-directed. The rates of dephosphorylation of histones 1, 2A, and 2B by the phosphatase were 4- to 12-fold more rapid at low (sub-micromolar) concentrations of free Ca2+ than at high (200 microM) Ca2+ in incubations containing CDR, but they were unaffected by Ca2+ in incubations without CDR. The addition of stoichiometric quantities of calmodulin increased the apparent Km of the phosphatase for the various histones 2- to 6-fold, while maximal velocities were 4- to 12-fold higher at low than at high added Ca2+. The inhibitory effect of Ca2+ on histone dephosphorylation was immediately reversible by chelation of Ca2+ with EDTA. Ca2+-dependent inhibition of histone 1 or 2B phosphatase activities was also produced by rabbit skeletal muscle troponin C, but not by rabbit skeletal muscle parvalbumin, by poly(L-aspartate) or poly(L-glutamate). The phosphorylated fragment from the NH2-terminal region of either H2A (generated by treatment with N-bromosuccinimide) or H2B (generated by treatment with cyanogen bromide) was dephosphorylated by the phosphatase, with the rates of dephosphorylation being reduced 3- to 6-fold by Ca2+ in incubations containing CDR.
...
PMID:Interaction of calmodulin with histones. Alteration of histone dephosphorylation. 625 89

Under certain physiological conditions a change in the phosphorylation of histones in mouse epidermis in vivo was observed. Thus a single local application of the tumor-promoting mitogen 12-O-tetradecanoylphorbol-13-acetate caused a long-lasting increase of histone H1 phosphorylation which paralleled stimulated cell proliferation. Injection of the antimitotic beta-adrenergic agonist isoproterenol led to a temporary decrease in the rate of phosphorylation of H1, H2A and H2B immediately after cyclic AMP accumulation. A complete protein phosphorylation system could be demonstrated in mouse epidermis homogenates. The following enzyme activities were partially purified and characterized: a cyclic AMP-dependent histone kinase; a 'casein kinase' and an 'unspecific' protein kinase; a histone-specific protein phosphatase; and two 'unspecific' phosphoprotein phosphatases. In addition, a stimulatory effect of cyclic GMP on histone phosphorylation was observed. The enzymes were found to be predominantly localized in the 105000 X g supernatant, but a small proportion of protein kinase and phosphatase activity could be regularly demonstrated in cell nuclei.
...
PMID:Histone phosphorylation in phorbol ester stimulated and beta-adrenergically stimulated mouse epidermis in vivo and characterization of an epidermal protein phosphorylation system. 626 86

Pig heart phosphoprotein phosphatase [phosphoprotein phosphophydrolase, EC 3.1.3.16] of Mr 224,000 was dissociated by gel-filtration on Sephacryl S-300, into an active subunit (alpha subunit) of Mr 31,000 and inactive subunits of higher molecular weight in the presence of 6 M urea. After the removal of urea, these subunits reassociated, forming two enzyme forms of Mr 237,000 (Form 1) and Mr 123,000 (Form 2). Form 2 was produced by association of the alpha subunit with an inactive subunit (beta subunit) of Mr 80,000, while Form 1 was formed by combination of the alpha subunit with a complex of inactive subunits which was eluted from a Sephadex G-150 column in fractions of molecular weight range greater than 80,000. The dissociation and reassociation of the subunits of Form 1 by the same urea method produced not only Form 1, but also significant amounts of Form 2, indicating that the inactive subunits of Form 1 were a complex of the beta subunit with another inactive subunit(s). The molecular parameters and other properties of Form 1 were very close to those of the original enzyme. By the conversion of Form 1 to Form 2, the activities of Form 1 towards phosphorylase a and glycogen synthetase b were enhanced 2-3 fold with no significant change in activity towards P-H1 histone or in response to the stimulatory effect of Mg(CH3COO)2 on the dephosphorylation of P-H2B histone. However, removal of the beta subunit from From 2 resulted in strong suppression of activity towards P-H1 histone and response to the salt effect with lesser effects on the activities of Form 2 towards phosphorylase a and glycogen synthase b.
...
PMID:Reconstitution of urea-dissociated subunits of a pig heart phosphoprotein phosphatase. 627 90

A partially purified pig heart phosphoprotein phosphatase was dissociated into three distinct components, namely alpha, beta, and gamma, by gel filtration on Sephacryl S-200 followed by chromatography on DEAE-Sephadex in the presence of 6 M urea. Although alpha itself had phosphatase activities toward P-H2B histone, P-H1 histone, phosphorylase a, and glycogen synthase b, beta and gamma had no activity toward these substrates even in the presence of 1 mM Mn2+. The beta component (Mr = 80,000) combined with alpha (Mr = 31,000) in the absence of urea to produce Form 2 (Mr = 123,000) with concomitant increase in P-H1 histone phosphatase activity and Mg2+ requirement for P-H2B histone phosphatase activity (Imazu, M., Imaoka, T., Usui, H., Kinohara, N., and Takeda, M. (1981) J. Biochem. 90, 851-862). The gamma component (Mr = 62,000) reassociated with Form 2 to produce Form 1 (Mr = 199,000) which was similar to the original phosphoprotein phosphatase in substrate specificity and Mg2+ requirement. Binding of gamma to Form 2 strongly suppressed the phosphatase activities toward phosphorylase a and glycogen synthase b with marginal effects on the other phosphatase activities and Mg2+ requirement. However, gamma alone could not associate with alpha. The gamma component was sensitive to treatment with heat (60 degrees C for 2 min) or trypsin and was resistant to treatment with DNase or RNase. The pig heart phosphoprotein phosphatase was further purified to near homogeneity, as judged by polyacrylamide gel electrophoresis. Sodium dodecyl sulfate gel electrophoresis revealed that the purified enzyme (Mr = 171,000) was composed of three polypeptide components, namely alpha', beta', and gamma' with molecular weights of 34,000, 69,000, and 56,000, respectively. The component stoichiometry was determined to be alpha' 1 beta' 1 gamma' 1 by densitometric tracing of the Coomassie blue-stained bands on the acrylamide gel. After dissociation of alpha ' and other components by gel filtration of the purified enzyme on Sephacryl S-200 in the presence of 6 M urea, one alpha ' combined with one beta' to produce Form 2' of Mr = 106,000. Since Form 1 and the purified enzyme as well as Form 2 and Form 2' had similar catalytic properties and s20,w values, respectively, component compositions are suggested to be alpha 1 beta 1 gamma 1 for Form 1 and alpha 1 beta 1 for Form Form 2.
...
PMID:Resolution and reassociation of three distinct components from pig heart phosphoprotein phosphatase. 629 3


1 2 Next >>

---