Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phosphorylation of H1 histones by cyclic AMP-dependent protein kinase may be an important transcriptional control mechanism. We have used affinity chromatography to examine the effect of phosphorylation by this enzyme on the DNA-binding properties of calf thymus H1 histones and two highly basic H1 homologues from condensed and transcriptionally silent nuclei: duck erythrocyte H5 and Strongylocentrotus purpuratus sperm H1. Without in vitro phosphorylation, all three histones were eluted from native DNA-Sephadex G-25 columns at salt concentrations which closely resembled those required to extract these histones from nuclei or chromatin. When a small portion of radioactively phosphorylated histone was chromatographed with untreated carrier histone, the phosphorylated species was consistently eluted from the DNA column at slightly lower salt concentrations than the main histone peak. Rechromatography experiments showed that in vitro phosphorylation of H1 can shift its elution position to lower salt concentrations.
Biochim Biophys Acta 1979 Sep 27
PMID:Phosphorlyation of H1 and H5 histones by cyclic AMP-dependent protein kinase reduces DNA binding. 22 45

A novel variant of S49 mouse lymphoma cells is described which is resistant to growth arrest and cytolysis by dibutyryl cyclic AMP but, in contrast to previously described variants, has normal cyclic AMP-dependent protein kinase. The variant is also resistant to N6-monobutyryl cAMP but is sensitive to killing by 8-bromo cAMP and cholera toxin. Extracts of the variant appear to contain wild type levels of both O2'-butyrylesterase and cyclic AMP phosphodiesterase activities. Accumulation of exogenous [3H]dibutyryl cyclic AMP is reduced in the variant suggesting a defect in either uptake or secretion of the analog or its metabolic products. Accumulation of cyclic AMP in variant cells after stimulation of adenylate cyclase with either isoproterenol or cholera toxin is also reduced compared with wild type cells, although cyclase activity of membranes prepared from the variant cells is normal. Extracellular accumulation of cyclic AMP after stimulation of variant cells with isoproterenol is greater than that found with wild type cells. It is concluded that the variant has an alteration in its cyclic AMP secretion mechanism resulting in more efficient extrusion of cyclic AMP than in wild type cells.
J Cell Physiol 1979 Sep
PMID:A variant of S49 mouse lymphoma cells with enhanced secretion of cyclic AMP. 22 56

A comparative study of in vitro and in vivo phosphorylation of murine mammary tumour virus, a type Brna virus, is reported. The protein kinase activity associated with murine mammary tumour virus catalysed the in vitro phosphorylation of endogenous virus polypeptides. This kinase activity required a divalent metal cation, a non-ionic detergent, and was stimulated in the presence of dithiothreitol. Exogenous cyclic AMP was not required. The 32P-labelled products of the in vitro reaction were completely sensitive to pronase digestion and the phosphate was attached mainly by phosphomonoester linkage to serine residues. As determined by SDS-polyacrylamide gel electrophoresis, heterogeneous labelling of major and minor virus polypeptides was observed under in vitro conditions. In contrast, the in vivo labelling of type B virus produced by a continuous cell line (MuMT-73), established from pooled mammary adenocarcinomas of Balb/cfC3H mice, demonstrated specific phosphoproteins associated with murine mammary tumour virus. The major phosphorylated proteins were found to have mol. wt. of 18 000 and 12 000 (p18 and p12) after isolation by molecular sieving chromatography and analysis by gel electrophoresis.
J Gen Virol 1979 Sep
PMID:In vivo and in vitro phosphorylation of murine mammary tumour virus proteins. 23 Oct 88

Oxidized glutathione (GSSG) (0.02-0.5 mM) inhibits reticulocyte lysates by a mechanism similar to that observed in heme deficiency. Incubation of hemin-supplemented postribosomal supernates with GSSG results in the activation of a translational inhibitor [I(GSSG)]. The activation of I(GSSG) is enhanced by the presence of an energy-regenerating system. The simultaneous addition of 1 mM dithiothreitol blocks the activation of the GSSG-induced inhibitor; however, once inhibitor is formed, its activity is not affected by 1 mM dithiothreitol. GSSG-treated postribosomal supernates and partially purified preparations of I(GSSG) inhibit protein synthesis in hemin-supplemented lysates with biphasic kinetics. Inhibition by I(GSSG) is blocked by cyclic AMP (2-10 mM) and is potentiated by ATP (2 mM). The inhibition is also blocked or reversed by eukaryotic initiation factor eIF-2. The activation of I(GSSG) is accompanied by an increased cyclic AMP-independent protein kinase activity which phosphorylates the 38,000-dalton component (alpha subunit) of eIF-2; however, GSSG treatment of supernates does not alter the activity of the cyclic AMP-independent protein kinase activity that phosphorylates the 49,000-dalton polypeptide component (beta subunit) of eIF-2. These data indicate that GSSG treatment of reticulocyte lysates results in the activation of a protein kinase with inhibitory and phosphorylation properties similar to those of the heme-regulated cyclic AMP-independent protein kinase which is activated in heme deficiency.
Proc Natl Acad Sci U S A 1978 Sep
PMID:Inhibition of protein synthesis initiation by oxidized glutathione: activation of a protein kinase that phosphorylates the alpha subunit of eukaryotic initiation factor 2. 27 1

The activity of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase [HMG-CoA reductase; mevalonate:NADP(+) oxidoreductase (CoA-acylating), EC 1.1.1.34] can be modulated in vitro by a phosphorylation-dephosphorylation reaction sequence. A microsomal reductase kinase catalyzes the phosphorylation of HMG-CoA reductase and histones. Histone phosphorylation was enhanced 2- to 3-fold by cyclic AMP. Reductase kinase exists in interconvertible active and inactive forms. Incubation of reductase kinase with phosphoprotein phosphatase resulted in a time-dependent decrease in the ability of reductase kinase to catalyze the phosphorylation of histones and to inactivate HMG-CoA reductase. Incubation of phosphoprotein phosphatase-inactivated reductase kinase with [gamma-(32)P]ATP plus Mg(2+) and a partially purified protein kinase designated reductase kinase kinase resulted in parallel increases in protein-bound (32)P radioactivity and ability to inactivate HMG-CoA reductase. Incubation of (32)P-labeled reductase kinase with phosphoprotein phosphatase resulted in a time-dependent loss of protein-bound (32)P radioactivity and a decrease in the ability to inactivate HMG-CoA reductase. Polyacrylamide gel electrophoresis of purified reductase kinase incubated with reductase kinase kinase and [gamma-(32)P]ATP plus Mg(2+) revealed that the (32)P radioactivity and reductase kinase enzymic activity were located in a single electrophoretic position. Dephosphorylation of (32)P-labeled purified reductase kinase with phosphoprotein phosphatase was associated with significant loss of radioactivity and enzymic activity in the protein band ascribed to reductase kinase. These results provide evidence that the activity of reductase kinase, like HMG-CoA reductase, is modulated by a reversible phosphorylation-dephosphorylation reaction sequence.
Proc Natl Acad Sci U S A 1979 Sep
PMID:Characterization and regulation of reductase kinase, a protein kinase that modulates the enzymic activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. 29 71

An increased in vitro phosphorylation of nonhistone nuclear proteins (NHP) was observed in the nuclei isolated from rabbit lymphocytes which had been stimulated with anti-Ig for 4 h. No concomitant increase of phosphorylation in histones or 0.14 M NaCl-soluble proteins was observed. The increase of in vitro phosphorylation of NHP was also observed in the nuclei isolated from nonstimulated cells when these nuclei were preincubated for 2 h with cell-free extracts from anti-Ig-stimulated cells. The active substance in cell-free extracts was maximally induced when lymphocytes were stimulated with anti-Ig for 2 h. The induction of an increased phosphorylation of NHP in nonstimulated nuclei with the cell-free extracts was not due to decrease of the adenosine triphosphate pool in the extracts from anti-Ig-stimulated cells. The active substance in cell-free extracts was not NHP-protein kinase itself, but it probably activated NHP-protein kinase in quiescent nuclei. The active substance was nondialyzable and probably protein. It was resistant against heating at 56 degrees C for 30 min, but the activity was completely destroyed by heating at 90 degrees C for 30 min. The active substance may be responsible for the transduction of the membrane-mediated signals given through Ig receptors to nuclei.
J Exp Med 1977 Sep 01
PMID:Induction and properties of cytoplasmic factor(s) which enhance nuclear nonhistone protein phosphorylation in lymphocytes stimulated by anti-Ig. 30 2

A physiologically and biochemically realistic model of the regulation of pyruvate dehydrogenase complex (PDH) was constructed for the perfused rat heart. It includes conversion between inactive (phospho) and active (dephospho) forms by a specific protein kinase (PDHK) and phosphoprotein phosphatase (PDHP). The activity of the tightly bound PDHK is influenced by synergistic activation/inhibition by acetyl CoA/CoASH and NADH/NAD. PDHK in this simulation was more sensitive to the fraction of ADP that was Mg2+-chelated than to the ATP-to-ADP ratio. Ca2+ stimulates binding of Mg2+-dependent PDHP to the complex; the bound enzyme was considered to be the active species. The fraction of PDH in the active form, rather than substrate and inhibitor levels, determines PDH activity under these conditions. This fraction depends on the present value and recent history of the difference between PDHK and PDHP activities. Both of these are active continuously and continuously control PDH.
Am J Physiol 1979 Sep
PMID:Computer simulation of metabolism in pyruvate-perfused rat heart. III. Pyruvate dehydrogenase. 47 88

In freshly prepared erythrocyte membranes from normal individuals and from patients with Duchenne progressive muscular dystrophy the endogenous protein kinase and the cAMP stimulated phosphorylation was identical for the three main 32P proteins including spectrin (protein band II). Another enzyme, adenylate cyclase, was found unchanged. Altered protein kinase and adenylate cyclase has been reported in this disorder. We have no explanation for these discrepancies.
Clin Chim Acta 1978 Sep 15
PMID:Protein kinase and adenylate cyclase of erythrocyte membrane from patients with Duchenne muscular dystrophy. 69 36

Pyruvate kinase type A was purified from pig kidney with a yield of 9%. The final enzyme fraction had a specific activity of 500 units/mg of protein. The enzyme appeared to be homogeneous on polyacrylamide gel electrophoresis in detergent and in ultracentrifugation experiments. The molecular weight of the enzyme was found to be 210,000 with the use of ultracentrifugation and 249,000 at gel chromatography. The sedimentation coefficient (S degrees 20, w) was calculated to be 9.8 S. For the reduced and alkylated pyruvate kinase, a molecular weight of 60,000 was found with the use of several methods. The Stokes radius for the enzyme was calculated to be 56 A. No NH2-terminal amino acid was detected in the enzyme, and the only findings in carbohydrate analyses of the kidney pyruvate kinase were trace amounts of glucose. The isoelectric point of the enzyme was estimated to be pH 5.6. Pig kidney pyruvate kinase type A was not phosphorylated on incubation with ATP and cyclic 3':5'-AMP-dependent protein kinase. The amino acid compositions of pig kidney and pig muscle pyruvate kinases were very similar and differed clearly from that of pig liver pyruvate kinase.
J Biol Chem 1977 Sep 10
PMID:Purification and characterization of pig kidney pyruvate kinase (type A). 89 98

The peptide compositions of rabbit skeletal- and canine cardiac-muscle sarcoplasmic reticulum preparations have been compared by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The cardiac preparations contain many proteins in addition to the 105 000 dalton peptide which has been previously identified as the Ca2+ stimulated ATPase. Four peptide components iodinated in the presence of either free or Sepharose 4B-bound lactoperoxidase have molecular weights of 130 000 (component I), 105 000 (component II), 52 000 (component III) and 47 000 (component IV). Comparison of the labelling patterns in the presence of the detergent Triton X-100 suggests that components I, III and IV have part of their peptide internally located. Although part of component II is externally accessible to free lactoperoxidase, its iodination is decreased by Triton X-100. Iodination of phospholamban, the 22 000 dalton substrate for cyclic AMP-dependent protein kinase, was not observed under the conditions investigated.
Biochim Biophys Acta 1977 Sep 27
PMID:Lactoperoxidase-coupled iodination of cardiac sarcoplasmic reticulum proteins. 90 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>