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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. At least two classes of high-affinity cyclic AMP-binding proteins have been identified: those derived from cyclic AMP-dependent protein kinases (regulatory subunits) and those that bind a wide range of adenine analogues (adenine analogue-binding proteins). 2. In fresh-tissue extracts, regulatory subunits could be further subdivided into 'type I or 'type II' depending on whether they were derived from 'type I' or 'type II' protein kinase [see Corbin et al. (1975) J. Biol. Chem. 250, 218-225]. 3. The adenine analogue-binding protein was detected in crude tissue supernatant fractions of bovine and rat liver. It differed from the regulatory subunit of cyclic AMP-dependent protein kinase in many of its properties. Under the conditions of assay used, the protein accounted for about 45% of the binding of cyclic AMP to bovine liver supernatants. 4. The adenine analogue-binding protein from bovine liver was partially purified by DEAE-cellulose and Sepharose 6B chromatography. It had mol.wt. 185000 and was trypsin-sensitive. As shown by competition and direct binding experiments, it bound adenosine and AMP in addition to cyclic AMP. At intracellular concentrations of adenine nucleotides, binding of cyclic AMP was essentially completely inhibited in vitro. Adenosine binding was inhibited by only 30% under similar conditions. 5. Rat tissues were examined for the presence of the adenine analogue-binding protein, and, of those examined (adipose tissue, heart, brain, testis, kidney and liver), significant amounts were only found in the liver. The possible physiological role of the adenine analogue-binding protein is discussed. 6. Because the adenine analogue-binding protein or other cyclic AMP-binding proteins in tissues may be products of partial proteolysis of the regulatory subunit of cyclic AMP-dependent protein kinase, the effects of trypsin and aging on partially purified protein kinase and its regulatory subunit from bovine liver were investigated. In all studies, the effects of trypsin and aging were similar. 7. In fresh preparations, the cyclic AMP-dependent protein kinase had mol.wt. 150000. Trypsin treatment converted it into a form of mol.wt 79500. 8. The regulatory subunit of the protein kinase had mol.wt. 87000. It would reassociate with and inhibit the catalytic subunit of the enzyme. Trypsin treatment of the regulatory subunit produced a species of mol.wt. 35500 which bound cyclic AMP but did not reassociate with the catalytic subunit. Trypsin treatment of the protein kinase and dissociation of the product by cyclic AMP produced a regulatory subunit of mol.wt. 46500 which reassociated with the catalytic subunit. 9. These results may be explained by at least two trypsin-sensitive sites on the regulatory subunit. A model for the effects of trypsin is described.
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PMID:Adenosine 3':5'-cyclic monophosphate-binding proteins in bovine and rat tissues. 1 84

In rabbit heart homogenates about 50% of the cAMP-dependent protein kinase activity was associated with the low speed particulate fraction. In homogenates of rat or beef heart this fraction represented approximately 30% of the activity. The percentage of the enzyme in the particulate fraction was not appreciably affected either by preparing more dilute homogenates or by aging homogenates for up to 2 h before centrifugation. The particulate enzyme was not solubilized at physiological ionic strength or by the presence of exogenous proteins during homogenization. However, the holoenzyme or regulatory subunit could be solubilized either by Triton X-100, high pH, or trypsin treatment. In hearts of all species studied, the particulate-bound protein kinase was mainly or entirely the type II isozyme, suggesting isozyme compartmentalization. In rabbit hearts perfused in the absence of hormones and homogenized in the presence of 0.25 M NaCl, at least 50% of the cAMP in homogenates was associated with the particulate fraction. Omitting NaCl reduced the amount of particulate-bound cAMP. Most of the particulate-bound cAMP was probably associated with the regulatory subunit in this fraction since approximately 70% of the bound nucleotide was solubilized by addition of homogeneous catalytic subunit to the particulate fraction. The amount of cAMP in the particulate fraction (0.16 nmol/g of tissue) was approximately one-half the amount of the regulatory subunit monomer (0.31 nmol/g of tissue) in this fraction. The calculated amount of catalytic subunit in the particulate fraction was 0.18 nmol/g of tissue. Either epinephrine alone or epinephrine plus 1-methyl-3-isobutylxanthine increased the cAMP content of the particulate and supernatant fractions. The cAMP level was increased more in the supernatant fraction, possibly because the cAMP level became saturating for the regulatory subunit in the particulate fraction. The increase in cAMP was associated with translocation of a large percentage of the catalytic subunit activity from the particulate to the supernatant fraction. The distribution of the regulatory subunit of the enzyme was not significantly affected by this treatment. The catalytic subunit translocation could be mimicked by addition of cAMP to homogenates before centrifugation. The data suggest that the regulatory subunit of the protein kinase, at least that of isozyme II, is bound to particulate material, and theactive catalytic subunit is released by formation of the regulatory subunit-cAMP complex when the tissue cAMP concentration is elevated. A model for compartmentalized hormonal control is presented.
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PMID:Compartmentalization of adenosine 3':5'-monophosphate and adenosine 3':5'-monophosphate-dependent protein kinase in heart tissue. 1 21

A protein kinase activity has been detected in two strains of murine Oncornaviruses, MSV/MLV and EFV. This activity phosphorylates not only endogenous viral proteins but also exogenous substrates (histones and phosvitin). The stimulation of enzyme activity by detergents along with the increase of specific activity in viruses treated with trypsin during purification suggest that the enzyme is located in the viral particle.
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PMID:[Evidence of protein kinase activity in 2 murine oncornaviruses]. 7 Dec 20

Phosphorylation of skeletal muscle glycogen synthase catalyzed by a protein kinase is stimulated up to 10-fold by the calcium-dependent regulator (CDR) protein. Half-maximal stimulation requires about 1 microgram of CDR/ml. Phosphorylation by the CDR-dependent synthase kinase is more rapid at pH 8.6 than at pH 6.8 and is blocked by ethylene glycol bis(beta-aminoethyl-ether)N,N'-tetraacetic acid and trifuloperazine. Approximately 60 to 70% of the phosphate is incorporated into the trypsin-insensitive region of glycogen synthase resulting in conversion of the a form to the b form of the enzyme. The CDR-dependent synthase kinase is not myosin light chain kinase, as this enzyme does not phosphorylate glycogen synthase. Furthermore, synthase phosphorylation by the cAMP-dependent protein kinase catalytic subunit is not affected by CDR. The possibility that CDR-dependent synthase kinase may be phosphorylase kinase is being investigated.
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PMID:Stimulation of glycogen synthase phosphorylation by calcium-dependent regulator protein. 10 93

Protein kinase isolated from rabbit skeletal muscle can be reversibly converted from the cAMP dependent form to the indepent form by chaotropic salts and urea. A similar but irreversible conversion can also be induced by trypsin digestion of the holoenzyme. The dissociation of cAMP dependent protein kinase by low concentrations of thiocyanate raises the possibility of isolating both native regulatory and catalytic subunits. From various changes in enzymatic activity caused by urea and trypsin perturbation, it is proposed that the conversion of protein kinase from the cAMP dependent to the independent form is due primarily to preferential modification of the regulatory subunit of the holoenzyme.
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PMID:Rabbit skeletal muscle protein kinase. Conversion from cAMP dependent to independent form by chemical perturbations. 16 29

The interaction between pyridoxal 5'-phosphate and the convertible serine of glycogen phosphorylase has been investigated by using: specific interconverting enzymes, phosphorylase kinase and phosphorylase phosphatase; effectors, glucose and glucose 6-phosphate; and a protein kinase and trypsin. Both phosphorylase kinase and phosphorylase phosphatase utilized the native protein while having little influence on the apoprotein. Removal of a peptide containing the critical serine residue gave phosphorylase b' from which the pyridoxal 5'-phosphate in phosphorylase has an important effect on enzymic interconversion.
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PMID:Pyridoxal phosphate-dependent conformational states of glycogen phosphorylase as probed by interconverting enzymes. 16 24

Two tryptic phosphopeptides containing the sites on the alpha and beta subunits of phosphorylase kinase which are phosphorylated by protein kinase, dependent on adenosine 3':5'-monophosphate (cyclic AMP), have been isolated and their amino acid sequences have been determined. 32P-labelled phosphorylase kinase, containing 1.9 mol phosphate per mol enzyme, was digested with an equimolar quantity of trypsin for 2.5 min at pH 7.0, 20 degrees C. This treatment released nearly all the 32P radioactivity associated with the beta subunit as trichloroacetic-acid-soluble material. Only a small proportion of the 32P radioactivity associated with the alpha subunit was solubilised, the remainder being removed in the trichloroacetic acid pellet. The beta-subunit tryptic phosphopeptide was completely resolved from traces of the alpha-subunit phosphopeptide by gel filtration on Sephadex G-25. Further purification by peptide mapping separated the phosphopeptide into four components, each derived from the same nine-amino-acid segment of the betachain, which was found to possess the sequence: Gln-Ser-Gly-Ser(P)-Val-Ile-Tyr-Pro-Leu-Lys. The four components were produced by the partial cyclisation of the N-terminal glutaminyl residue, and by the presence of two alleles for the beta subunit in the rabbit population, which led to a valine-isoleucine ambiguity. The alpha-subunit phosphopeptide was liberated from the trichloroacetic acid pellet by redigestion with trypsin. It was the largest component in the digest which remained soluble in 5% trichloroacetic acid, and obtained in a highly purified form by a single filtration on Sephadex G-50. The peptide comprised 39 amino acids of which nine were serine and three were threonine residues. Only one residue, the serine at position three from the amino terminus, was phosphorylated. The amino-terminal sequence of the peptide was shown to be: Arg-Leu-Ser(P)-Ile-Ser-Thr-Glu-Ser-Glx-Pro-Asx-Gly. The sequences confirm the stoichiometry of the reaction and the absolute specificity of cyclic-AMP-dependent protein kinase for just two of the 200 serine residues in the enzyme. These results and an inspection of the rate of phosphorylation of a number of skeletal muscle proteins, including each enzyme of the glycolytic pathway, lead to the conclusion that cyclic-AMP-dependent protein kinase is an extremely specific enzyme. The molecular basis of this specificity is discussed.
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PMID:The hormonal control of activity of skeletal muscle phosphorylase kinase. Amino-acid sequences at the two sites of action of adenosine-3':5'-monophosphate-dependent protein kinase. 16 50

Differences exist in the rates at which hormones are inactivated by, or dissociate from, their target tissues. The present studies examined the binding of biologically active TSH to thyroid slices and compared its characteristics to those of PGE. Canine thyroid slices were initally incubated with 5 mU/ML OF BOVINE TSH (TSH-Inital) for 15 min, washed and incubated in media free of hormone for 3 hr. At the conclusion of this second incubation period all slices were again washed. Some were then transferred to media containing 10-2M theophylline for a final 10 min incubation and subsequent measurement of cAMP and protein kinase, while others were transferred to media containing (l-14C)glucose without theophylline for a final 45 min incubation to assess glucose oxidation. Identically treated slices never exposed to TSH served as controls, while others were exposed to TSH only during the final 10 or 45 min incubation periods (TSH-Final). cAMP content determined after significantly increased in TSH-Initial (mean 2.98 plus or minus 0.36 (se) pmol/mg wet wt) compared to control (0.35 plus or minus 0.04), but was less than that in TSH-Final (5.76 plus or minus 0.51). This phenomenon was not unique to canine thyroid, since comparable results were noted in studies of human, bovine or porcine thyroid slices. The protein kinase activity ratio (-cAMP/+cAMP) and glucose oxidation of TSH-Initial were also significantly increased above control following the final 10 min or 45 min incubations respectively. Addition of trypsin to the 3 h incubation abolished the subsequent increase in cAMP in TSH-Initial, while addition of TSH antiserum appreciably reduced this increase. These results are consistent with the persistent binding of biologically active TSH to thyroid. By contrast, evidence of similar persistent binding of PGE1 to thyroid, glucagon to liver, or parathyroid hormone to renal cortex was lacking when assessed by an identical experimental procedure. Differences between the duration of interaction of TSH and PGE1 with thyroid may be dependent or a more gradual dissociation to tissue bound TSH, a more rapid inactivation of bound-PGE1, or both.
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PMID:Evidence for persistent binding of biologically active thyrotropin to thyroid in vitro. 16 69

Recently accumulated knowledge allows more precise comparison of the structural (and possibly evolutionary) relationships of several different animal rhabdoviruses: vesicular stomatitis virus, rabies virus, Kern Canyon virus, and spring viremia of carp virus. Each virus is composed primarily of a glycoprotein, an RNA-associated nucleoprotein, and one or two membrane proteins. Vesicular stomatitis virus group viruses contain lesser amounts of two additional distinct polypeptides, NS and L. The separate viruses undergo structural polypeptide phosphorylation in vivo according to characteristic patterns. In vesicular stomatitis virus the NS protein is selectively phosphorylated. In rabies group viruses and in spring viremia of carp virus, the nucleoprotein is the predominant phosphoprotein; in these viruses only the phosphorylated moiety is selectively cleaved off with trypsin. In Kern Canyon virus, only membrane protein and glycoprotein are weakly phosphorylated. Each virus possesses a virion-bound protein kinase. Vesicular stomatitis virus group viruses, Kern Canyon virus, and spring viremia of carp virus only contain virion-bound transcriptases of respectively decreasing levels of activity demonstrable in vitro. Vesicular stomatitis and Kern Canyon viruses replicate efficiently in enucleated cells; rabies virus does not. Based upon these observations, it is suggested that vesicular stomatitis virus may represent the most highly evolved of these rhabdoviruses, whereas spring viremia of carp and Kern Canyon viruses may represent "evolutionary links" between the vesicular stomatitis and rabies virus groups.
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PMID:Structure-function relationships and mode of replication of animal rhabdoviruses. 16 94

Rat hearts were perfused with epinephrine and/or 1-methyl-3-isobutylxanthine for 2 min. These agents raised the concentration of cAMP and increased the fraction of cAMP-dependent protein kinase (EC 2.7.1.70) in the active form. However, the content of cAMP-dependent protein kinase in the soluble fraction of homogenates of these hearts was reduced and the amount in the particulate fraction was increased. A similar redistribution was obtained by adding cAMP to homogenates of control hearts. The reduction in soluble protein kinase content was due to apparent binding of the free catalytic subunit of the enzyme to particulate material (12,000 times g pellet) in media of low ionic strength (smaller than 100 mM KCl). The amount bound was, therefore, proportional to the dissociation of the holoenzyme. The binding was not altered by prior boiling or trypsin treatment of the particulate material, but it was prevented or reversed by the addition of 150 mM KCl. The catalytic subunit of the protein kinase from heart also bound to particulate fractions from liver or Escherichia coli and to various denatured proteins. These findings suggest that the protein kinase activity of membranes and particulate fractions has frequently been overestimated, since isolation of particulate materials has usually been carried out at low ionic strength. The data also imply that intracellular translocation of the protein kinase catalytic subunit, at least in heart tissue, is of questionable physiological significance.
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PMID:On the question of translocation of heart cAMP-dependent protein kinase. 16 13


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