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)

An endogenous protein kinase at the surface of Ehrlich cells has been studied. Using exogenous (gamma32P)ATP as a phosphoryl group donator, a transfer was demonstrated into endogenous acceptor protein(s) as well as to exogenous phosvitin. Seryl- and threonyl-residues isolated from the endogenous and exogenous acceptor protein were found to be labeled. The ratio between the labeled phosphorylserine and phosphorylthreonine was about 3.5:1 for both the endogenous acceptor of the intact cells and the exogenous acceptor. In similar experiments with a membrane preparation from Ehrlich cells, this ratio increased to about 7:1 provided the exogenous acceptor protein was absent. The results were independent of whether 1 X 10(-5) M dibutyryl cyclic AMP was used or not with intact cells and a membrane fraction mainly consisting of vesicles. Whether the regulatory subunit of the membrane-associated protein kinase was in cis- or trans-disposition to the catalytic subunit no binding and dependence of the cyclic nucleotide was observed. Since the purified membrane fraction was considered free from endogenous cyclic AMP, it was concluded that the membrane-associated protein kinase of Ehrlich cells is not dependent on cyclic AMP. The critical role of arginine for the cyclic AMP dependence of the serine-containing residue in the catalytic subunit is discussed.
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PMID:Phosphorylation of endogenous membrane proteins by endogenous protein kinase at the outer surface of Ehrlich cells. 18 75

A protein kinase, designed KII, has been purified 5000-fold from Novikoff ascites tumor cells. The purification procedure also allows for the purification of a second major protein kinase, designated KI, as well as RNA polymerase I and II. Purified KII has a sedimentation constant of 7.6 S and a Stokes radius of 39 A, suggesting a molecular weight of about 122000. Polyacrylamide gel electrophoresis of the enzyme in the presence of sodium dodecyl sulfate suggests the enzyme is composed of subunits of molecular weights 44 000, 40 000, and 26 000 present in a molar ratio of 1:1:2. Incubation of the enzyme alone in the presence of [gamma-32P]ATP results in the phosphorylation of the 26 000-dalton subunit. Protein kinase II actively phosphorylates phosvitin, casein, and nonhistone chromosomal proteins but does not phosphorylate basic proteins such as histones or protamine to an appreciable extent. Km values of 3.6 micron for ATP and 6.5 micronM for GTP were determined in the presence of 4mM Mg2+. The enzyme is neither stimulated by cyclic adenosine 3',5'-monophosphate or cyclic guanosine 3', 5'-monophosphate nor inhibited by the regulatory subunit of rabbit muscle protein kinase. Its activity is stimulated by KCl at concentrations below 0.2 M and inhibited by higher concentrations.
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PMID:Purification and characterization of Novikoff ascites tumor protein kinase. 19 79

The phosphorylation of phosvitin in vitro by a cyclic nucleotide-independent protein kinase (phosvitin kinase) derived from rooster liver is markedly stimulated by the divalent cation, Mg2+. In addition, the activity is further stimulated by low concentrations of the polyamines putrescine, spermidine and spermine leading to higher rates of phosphate incorporation than could be obtained at any concentration of Mg2+. Spermine is inhibitory at higher concentrations. The polyamines shift the Mg2+ requirement for maximal activity to lower concentrations. The activity of a cyclic AMP-dependent histone kinase from beef heart is not altered by the presence of polyamines. Heparin is a potent inhibitor of phosvitin kinase but has no effect on histone kinase. Polyribonucleotides (polyadenylic acid and transfer RNA) inhibit both types of kinases, but the degree of inhibition of phosvitin kinase is variable and depends upon the type of the polyanion present. Sermidine and spermine, but not Mg2+, efficiently counteract the inhibitory action of heparin and tRNA. The results suggest that, also in vivo, naturally occurring polyamines and polyanions such as tRNA may have a regulatory function on protein kinases.
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PMID:Effects of polyamines and polyanions on a cyclic nucleotide-independent and a cyclic AMP-dependent protein kinase. 19 31

A heat-and acid-stable protein inhibitor of phosphorylase phosphatase is present in a highly purified preparation of protein inhibitor of cyclic AMP-dependent protein kinase from rabbit skeletal muscle. Although these two inhibitors have strikingly similar properties to each other, such as sensitivity to trypsin and behavior on gel permeation chromatography, they can be separated by polyacrylamide disc gel electrophoresis. This indicates that the phosphatase-inhibitory and kinase-inhibitory activities reside with different protein species. The inhibition of both the enzymes is not altered by incubating the inhibitor preparation with a general phosphoprotein phosphatase, with phosvitin kinase, or with cyclic AMP-dependent protein kinase. Inhibition of phosphorylase phosphatase is of a non-competitive type supporting the idea that the phosphatase inhibitor is not an alternative substrate for the enzyme. Inhibition of phosphatase activity is selective in that it does no occur when phosphorylated histone or phosphorylated protamine are used as substrates.
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PMID:Protein inhibitors of phosphorylase phosphatase and cyclic AMP-dependent protein kinase from rabbit skeleta muscle. 19 98

A protein kinase which phosphorylated histone and protamine was partially purified from bovine cerebellum. Casein and phosvitin were inert as substrates. The enzyme did not require any cyclic nucleotide. A sulfhydryl compound such as 2-mercaptoethanol, glutathione, or cysteine was necessary for the reaction. The optimum pH was 8.5 to 9.0 Km values for ATP and whole histone were 3.3 X 10(-6) M and 150 microgram/ml, respectively. The optimum concentration of Mg2+ varied with histone fractions employed; with H2B histone as substrate the enzyme was most active at 50 to 100 nM Mg2", whereas with H1 and H2A histones the maximum activity was observed at 5 to 10 mM Mg2+ and with H3 and H4 histones the enzyme was active over a range of 5 to 75 mM Mg2+. The enzyme phosphorylated Ser-32 and Ser-36 in H2B histone and Ser-38 in H1 histone, although the reaction with Ser-36 in H2B histone was very slow. The molecular weight was 6.4 X 10(4). The sedimentation coefficient and Stokes radium were about 4.5 and 29 A, respectively. The enzyme showed heterogeneity upon isoelectrofocusing electrophoresis with isoelectric points of 5.6, 6.0, and 6.6. The enzyme was not inhibited by protein inhibitor nor by the regulatory subunit of cyclic AMP-dependent protein kinase. Preliminary analysis suggested that the enzyme was produced from its precursor protein by a limited proteolytic reaction.
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PMID:Studies on a cyclic nucleotide-independent protein kinase and its proenzyme in mammalian tissues. I. Purification and characterization of an active enzyme from bovine cerebellum. 19 93

Nuclear and cytoplasmic protein kinases were measured during the traverse of synchronous CHO cultures through G1 into S phase. Cells were synchronized by selective detachment of cells blocked in metaphase using colcemid. Nuclei were isolated and the protein kinases extracted from the nuclear preparation with 0.6 M NaCl. This procedure solubilized greater than 90% of the total protein kinase activity present in the nuclear preparation. DEAE chromatography of this extract showed 5 apparently different ionic forms of nuclear protein kinases. The nuclear protein kinases preferred casein and phosvitin to histone as substrates and were cyclic AMP-independent. Nuclear protein kinase activities increased greater than two-fold, when expressed as units of activity per cell nucleus, during G1 phase traverse, concomitant with a 70% increase in nuclear non-histone proteins (those soluble in 0.6 M NaCl). This resulted in only a 40% increase in the specific activities (units/microgram protein in 0.6 M NaCl extractable nuclear fraction) of these enzymes as cells progressed through G1 into S phase. This was in contrast to cytoplasmic cyclic AMP-dependent protein kinase activities which also increased two-fold during progression through G1 phase while total cellular protein increased less than 20%. Activation of, as well as synthesis of, cyclic AMP-dependent cytoplasmic protein kinases during G1 phase suggests a regulatory mechanism for precise temporal phosphorylation, whereas the constant specific activity in nuclear kinases during cell cycle is more compatible with the maintenance of bulk phosphorylation processes in the nucleus.
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PMID:Cytoplasmic and nuclear protein kinases during the cell cycle. 20 Feb 70

A cAMP-independent protein kinase from chicken liver phosphorylated and inactivated pyruvate kinase type M2 from the same tissue. Complete inactivation was reached when 4 mol of phosphate were incorporated/mol of tetrameric pyruvate kinase. The protein kinase bound with high affinity to pyruvate kinase type M2 (Km value for pyruvate kinase = 6 X 10(-10)M; it phosphorylated phosvitin and casein but not histones, ATP and GTP were substrates. The differences between the properties of this protein kinase in the interconversion of pyruvate kinase and that described previously are discussed.
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PMID:Inactivation of pyruvate kinase type M2 from chicken liver by phosphorylation, catalyzed by a cAMP-independent protein kinase. 20 May 42

Both cytosol and membranes of human erythrocytes display protein kinase activity towards exogenous protein substrates such as casein, phosvitin and histones. The histone kinase activity, unlike casein kinase, of both cytosol and membranes is increased by cyclic AMP. The protein kinase forms removed from the membranes with 0.7 M NaCl, phosphorylate only serine residues of both casein and histones through a mechanism cyclic AMP-independent. The protein kinase activity located in the cytosol (hemolysate) is due also to enzyme forms phosphorylating both serine and threonine residues of casein, in addition to forms phosphorylating only serine residues of casein and histones. Also the cytosol kinase forms, once partially purified by Sepharose 6B filtration, appear to be cyclic AMP-independent.
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PMID:Multiple forms of cytosol and membrane-bound protein kinase activity in human erythrocytes. 20 70

Protein kinase associated with rat liver microsomes was only partly extracted by treatment with 1.5 M KCl. The enzyme was solubilised by Triton X-100 or sodium deoxycholate at the same or slightly higher detergent concentrations than microsomal marker components. The enzyme activity increased 2-3 fold upon solubilisation. Three peaks with protein kinase activity (fractions MI, MII and MIII) were resolved on DEAE-cellulose chromatography. Fraction MIII but not fractions MI or MII was activated by adenosine 3':5'-monophosphate (cyclic AMP). All fractions catalysed the phosphorylation of protamine and histones but not that of casein or phosvitin. Fractions MI and MIII had a similar substrate specificity and phosphorylated histones at a relatively much higher rate than did fraction MII. The isoelectric points were 8.1 for fraction MI, 5.5 for fraction MII and 4.9 for fraction MIII. On incubation of fraction MIII with cyclic AMP it was split into two catalytically active components with pI 8.1 and 7.35. The component with pI 8.1 was predominant and corresponded to fraction MI. Five protein kinase peaks were resolved from rat liver cytosol by DEAE-cellulose chromatography. Three of them (fractions CIa, CIIb and CIII) had the same properties as each of the microsomal kinase fractions. A forth fraction (CIIa) was cyclic-AMP-dependent and had the same substrate specificity as fractions MI and MIII. Its pI was 5.1, and it was split into two components by cyclic AMP (pI 8.1 and 7.35). In binding studies fraction CIIb bound more efficiently to microsomes than fraction CIII, while fractions CIa, CIIa and the microsomal protein kinase fractions did not bind appreciably. When microsomes were treated with trypsin exposed protein kinase was inactivated and the latency of the remaining enzyme increased substantially. Most of fraction MII was inactivated by trypsin while fraction MIII was resistant. The possible orientation of protein kinase fractions MII and MIII in the microsomal membrane is discussed.
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PMID:Protein kinases of rat liver endoplasmic reticulum. Solubilisation, partial characterisation and comparison with protein kinases of rat liver cytosol. 20 48

Three protein kinases were distinguished in Trypanosoma gambiense extract. The enzymes preferred phosvitin, histone, and protamine as acceptor proteins, respectively. The amino acid residues of the acceptor proteins which were phosphorylated by these protein-kinase activities were serine and- to less extent- threonine. The protein kinase activities were neither affected by cyclic nucleotides nor by cyclic AMP receptors. The molecular weights of these protein kinases were determined to be greater than 200,000, 95000 and 37000, respectively. The activities of all three protein kinases were affected to varying degrees by nucleotides and nucleosides.
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PMID:Multiple protein kinases from Trypanosoma gambiense. 20 47


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