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

Highly purified preparations of hemin-controlled repressor of rabbit reticulocyte contain a 3':5'-cyclic AMP-indenpendent protein kinase activity that phosphorylates the low-molecular-weight (about 38,000) polypeptide chain of the initiation factor that forms a ternary complex with GTP and Met-tRNAf. These preparations also phosphorylate several polypeptide components of reticulocyte 40S ribosomal subunits. However, no significant levels of phosphorylation are observed when casein, histones, Artemia salina 40S ribosomal subunits, or other initiation factor fractions are used as substrates although high levels of phosphorylation are obtained with cruder preparations of the repressor. An antibody to these highly purified preparations of repressor has been obtained from the serum of immunized goats. Preincubation with immune goat IgG results in the neutralization of the inhibitory activity of the repressor, while normal IgG has no effect. Preincubation with immune IgG also abolishes the protein kinase activity responsible for the phosphorylation of the initiation factor and reticulocyte 40S subunits. Histone phosphorylation by crude repressor preparations, on the other hand, is unaffected by preincubation with immune IgG.
...
PMID:Specificity of the protein kinase activity associated with the hemin-controlled repressor of rabbit reticulocyte. 18 58

Purified protein synthesis initiation factors IF-E2 and IF-E3 from rabbit reticulocytes were phosphorylated in vitro with protein kinases isolated from the same source. The highest levels of phosphorylation resulted from incubation of the factors with a cyclic nucleotide-independent protein kinase previously shown to have specificity for acidic proteins. The extent of phosphorylation of initiation factor IF-E2 was between 0.3 and 0.4 mol of phosphate per mol of factor complex, with either ATP or GTP as phosphoryl donor. Initiation factor IF-E2 is composed of three nonidentical polypeptides; only the polypeptide with a molecular weight of 52,000 was phosphorylated. The extent of phosphorylation of initiation factor IF-E3 was between 0.7 and 1.0 mol of phosphate per mol of factor complex with GTP as phosphoryl donor; with ATP, less phosphorylation of the factor was obtained. Initiation factor IF-E3 is composed of 9 to 11 nonidentical polypeptides; only 2 of these, with molecular weights of 120,000 and 70,000, were phosphorylated. A lower level of phosphorylation of initiation factor IF-E3 was found with the cyclic AMP-dependent protein kinase; the polypeptide of molecular weight 140,000 was the major site of phosphorylation.
...
PMID:Phosphorylation in vitro of eukaryotic initiation factors IF-E2 and IF-E3 by protein kinases. 18 14

Previous reports from this laboratory and others have established that both the rabbit and human erythrocyte membranes contain multiple protein kinase and phosphate acceptor activities. We now report that these membranes also contain phosphoryl acceptor sites for the soluble cyclic AMP-dependent and -independent protein kinases from rabbit erythrocytes. The rabbit erythrocyte membrane, which does not contain a cyclic AMP-dependent protein kinase, has at least four polypeptides (Bands 2.1, 2.3, 4.5, and 4.8) which are phosphorylated in the presence of the soluble cyclic AMP-dependent protein kinases I, IIa, and IIb isolated from rabbit erythrocyte lysates. The resulting phosphoprotein profile is very similar to that obtained for the cyclic AMP-mediated autophosphorylation of human erythrocyte membranes. The activities of the soluble cyclic AMP-dependent protein kinases toward the membranes have been studied at several pH values. Although the substrate specificity of the three kinases is similar, polypeptide 2.3 appears to be phosphorylated to a greater extent by kinase IIa than by I or IIb. This occurs at all pH values studied. Also apparent is that the pH profile for membrane phosphorylation is different from that of histone phosphorylation. The phosphorylation of membrane proteins can also be catalyzed by the soluble erythrocyte casein kinases. These enzymes are not regulated by cyclic nucleotides and can use either ATP or GTP as their phosphoryl donor. Polypeptides 2.1, 2.9, 4.1, 4.5, 4.8, and 5 of both human and rabbit erythrocyte membranes are phosphorylated in the presence of GTP and the casein kinases. This reaction is optimal at pH 7.5. Experiments were performed to determine whether the phosphorylation of the membranes by the soluble and membrane-bound kinases is additive or exclusive. Our results indicate that after maximal autophosphorylation of the erythrocyte membranes, phosphoryl acceptor sites are available to the soluble cyclic AMP-dependent and -independent protein kinases. Furthermore, after maximal phosphorylation of the membranes with one type of soluble kinase, further 32P incorporation can occur as a result of exposure to the other type of soluble kinase.
...
PMID:Phosphorylation of rabbit and human erythrocyte membranes by soluble adenosine 3':5'-monophosphate-dependent and -independent protein kinases. 18 4

The initiation inhibitor of reticulocyte lysates has been shown by others to be associated with a 3':5'-cyclic-AMP-independent protein kinase that catalyzes the phosphorylation of the small (38,000 daltons) subunit of the polypeptide chain initiation factor eIF-2. This factor forms a ternary complex with Met-tRNAi and GTP which, on interaction with a 40S ribosome, gives rise to a 40S complex. Ternary complex formation is inhibited by prior incubation of partially purified eIF-2 with reticulocyte inhibitor and ATP. The relation between phosphorylation and inactivation of eIF-2 is indicated by the lack of inhibition when ATP is omitted. Translation in hemin-containing reticulocyte lysates is also inhibited by cyclic-AMP-dependent protein kinases or their catalytic subunits. They act by converting proinhibitor (inactive eIF-2 kinase) present in lysates to inhibitor (active eIF-2 kinase). This reaction is analogous to the conversion of inactive phosphorylase kinase to active phosphorylase kinase.
...
PMID:Role of 3':5'-cyclic-AMP-dependent protein kinase in regulation of protein synthesis in reticulocyte lysates. 19 1

The guanosine 3':5'-monophosphate-dependent protein kinase from bovine lung was purified to apparent homogeneity by affinity chromography using 8-2-aminoethylthio-cGMP coupled to Sepharose 4B. The kinase activity was purified approximately 6000-fold with an overall recovery of approximately 20%. The product isolated by affinity chromatography contained both cGMP-binding and cGMP-dependent histone kinase activity, indicating that the enzyme was not dissociated into regulatory and catalytic components by the immobilized cGMP derivative. The enzyme had a molecular weight of approximately 165,000 and a sedimentation coefficient of 7.8 S. The purified kinase displayed several characteristics similar to that of the partially purified enzyme including specificity for cGMP and stimulation by high concentrations of magnesium. On sodium dodecyl sulfate gels, only one major polypeptide chain was present having a molecular weight of approximately 81,000. This subunit bound 1 mol of cGMP and exhibited cGMP-dependent protein kinase activity. It is proposed that the native enzyme consists of two identical subunits (Mr=81,000), each of which binds cGMP and catalyzes protein phosphorylation.
...
PMID:Purification and subunit composition of guanosine 3':5'-monophosphate-dependent protein kinase from bovine lung. 19 62

An endogenous substrate for adenosine 3':5'-monophosphate-dependent protein kinase has been solubilized, and purified about 5,000-fold to apparent homogeneity, from a particulate fraction of bovine cerebral cortex enriched in synaptic membranes. This endogenous substrate, referred to as Protein I, is apparently specific to nervous tissue, and is composed of two types of polypeptides, present in a proportion of 1 (Protein Ia, 86,000 daltons) to 2 (Protein Ib, 80,000 daltons). In the presence of cAMP-dependent Protein I kinase purified from the same membrane fractions, Proteins Ia and Ib incorporated 0.83 and 0.81 mol of phosphate into serine/mol of peptide, respectively. Proteins Ia and Ib have similar amino acid compositions and have isoelectric points of 10.3 and 10.2, respectively. Both types of polypeptide have a relatively high content of glycine and proline, and both are degraded to a peptide of 48,000 daltons by highly purified collagenase, suggesting that Proteins Ia and Ib contain some sequences similar to those observed in collagen. The sedimentation coefficient of Protein Ia and Protein Ib was determined to be 2.9 S. The data suggest that both Protein Ia and Protein Ib have an elongated shape.
...
PMID:Adenosine 3':5'-monophosphate-regulated phosphoprotein system of neuronal membranes. I. Solubilization, purification, and some properties of an endogenous phosphoprotein. 19 3

The lactating mammary gland synthesizes and secretes large amounts of phosphoproteins that mainly are associated with the casein fraction of milk. The free amino acids and inorganic phosphate of blood serve as building materials for casein, and the final product appears in milk as a colloidal-sized particle, the casein micelle. According to our present concept, the biosynthesis of casein occurs in two steps: synthesis of the polypeptide chain, followed by phosphate addition. Phosphate groups are transferred to the nascent casein by a protein kinase localized in the Golgi apparatus. The enzyme uses adenosine 5'-triphosphate as the phosphate donor and requires divalent cations. Neighboring amino acids may be important in determining which serine residues in casein are phosphorylated. This review discusses historical and current research on the phosphorylation of casein.
...
PMID:Phosphorylation of casein by the lactating mammary gland: a review. 19 45

Synthetic polypeptides were employed as substrates in kinetic analyses of the reaction mechanism for the catalytic subunit of a cyclic AMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) from calf thymus. This enzyme preparation was shown to catalyze the transfer of phosphate from ATP to histone H1 from calf thymus, as well as to two synthetic polypeptides, Arg-Lys-Ala-Ser-Gly-Pro (H1-6) and Arg-Arg-Lys-Ala-Ser-Gly-Pro (H1-7), corresponding to the amino acid sequence about serine-38 in calf H1. A related, basic heptapeptide corresponding to a sequence from pig liver pyruvate kinase, Leu-Arg-Arg-Ala-Ser-Leu-Gly (K), was also a substrate. The stoichiometry of peptide phosphorylation was established in each case as the transfer of 1 mol of phosphate from the gamma position of MgATP to the serine hydroxyl of 1 mol of the peptide. Steady-state, initial-velocity, kinetic parameters were determined for each substrate, using various concentrations of ATP. Under the conditions used, all synthetic peptides reacted with greater maximum velocities than whole histone H1. Nevertheless, the K(m) for H1, 54 muM, was lower than the K(m) values of the synthetic substrates. The most efficient substrate was peptide K, which had a V(max) of 50.6 mumol/min per mg of kinase and a K(m) of 63 muM. In the absence of peptide substrate no ATPase activity was detectable at a sensitivity of 0.05% of the rate of peptide phosphorylation, suggesting that ATP is not cleaved to form an unstable phosphoenzyme complex. The data are consistent with a sequential reaction mechanism involving a ternary complex between enzyme, polypeptide substrate, and ATP.
...
PMID:Studies on the mechanism of phosphorylation of synthetic polypeptides by a calf thymus cyclic AMP-dependent protein kinase. 20 Sep 11

Affinity chromatography on cyclic AMP columns allowed a two-step isolation of the cyclic-AMP-binding proteins from bovine kidney cytosol. An AMP-binding protein (apparent molecular weight approximately 60 000) and large amounts of a low affinity binding protein ('P35'; apparent subunit size approximately 35 000) were obtained in practically pure form besides the high affinity binding proteins of the R type. Among the R proteins the dimer R2 of the regulatory subunit of protein kinase II (apparent subunit size approximately 54 000) represented the bulk material. Small amounts of monomer, of higher aggregates, and of a protein 'P49' (subunit size approximately 49 000) presumably identical with the regulatory subunit of protein kinase I were also detected. The R protein fraction of kidney also contained a high affinity binding protein of smaller size (designated as R'; molecular weight approximately 37 000) which appeared to be derived from protein R2 of protein kinase II by limited proteolysis. At all stages of purification, R protein and its aggregates could be quantitatively transformed into R' protein (or a closely related polypeptide) by several proteases including the relatively unspecific proteinase K. The degradation product exhibited unchanged cyclic-AMP-binding capacities but had largely lost the ability to inhibit the catalytic subunit C of protein kinase, to be phosphorylated by C, and to form a dimer. Preliminary experiments indicate that protein R' may be a natural component of kidney tissue.
...
PMID:Adenosine-3':5'-monophosphate-binding proteins from bovine kidney. Isolation by affinity chromatography and limited proteolysis of the regulatory subunit of protein kinase II. 20 61

The recently discovered heat-stable inhibitor protein of the Ca2+-activated cyclic nucleotide phosphodiesterase (Sharma, R. K., Wirch, E. & Warg, J. H. (1978) J. Biol. Chem., in press) has been purified 238 214-fold from bovine brain extract using an affinity column of the modulator protein--Sepharose 4B conjugate. The purified sample appears to be homogeneous as judged by sodium dodecyl sulphate (SDS) gel electrophoresis. The protein band has a mobility corresponding to that of a polypeptide of molecular weight 68 000. Since the heat-stable inhibitor protein has a molecular weight of 70 000 under nondenaturing conditions, it suggests that it is a monomeric protein. The protein has no inhibitory activity toward the cAMP-dependent protein kinase or protein phosphatase. The purified sample has been tested for various enzyme activities which include ATPase, GTPase, cAMP phosphodiesterase, cGMP phosphodiesterase, 5'-nucleotidase, and protein kinase. None of these activities are exhibited by the purified sample.
...
PMID:Purification of the heat-stable inhibitor protein of the Ca2+-activated cyclic nucleotide phosphodiesterase by affinity chromatography. 20 31


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

---