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)

The dephosphorylation of phospho-amino acids with alkaline phosphatase (AlPase) from calf intestine or Escherichia coli and the phosphorylation of bovine serum albumin (BSA) with epidermal growth factor (EGF) receptor kinase from human A431 epidermoid carcinoma cells were investigated by 31P NMR spectroscopy. The initial rates of the dephosphorylation of phospho-tyrosine (P-Tyr) and phosphoserine (P-Ser) with AlPase were essentially the same in the one-substrate system. In the two-substrate system (P-Tyr plus P-Ser), however, the ratio of the initial rate for P-Tyr vs. P-Ser was 2.4 to 4.5 depending on the buffer and pH conditions employed. This substantiates for the first time the specificity of AlPases to P-Tyr over P-Ser at the free amino acid level. In the stationary phase of the overall process, the dephosphorylation of P-Ser became slow compared to that of P-Tyr in the one-substrate system. The decrease in the rate for P-Ser was further pronounced in the two-substrate system. For this remarkable effect, the rephosphorylation of serine was responsible, as demonstrated in the reaction mixture containing serine, Pi, and AlPase. BSA phosphorylated by EGF receptor kinase exhibited sharp 31P resonances around 0 ppm at neutral pH, far distant from the peak positions (4.9 ppm) of histone H1 phosphorylated by cAMP-dependent protein kinase. These NMR data are directed evidence that BSA was phosphorylated exclusively at the tyrosyl residues, whereas the phosphorylation of histone H1 was at the seryl residues.
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PMID:Tyrosine-specific dephosphorylation-phosphorylation with alkaline phosphatases and epidermal growth factor receptor kinase as evidenced by 31P NMR spectroscopy. 282 Sep 50

Bovine kidney mitochondrial extracts contain an inactive protamine kinase and an inactive casein kinase. The protamine kinase was activated by chromatography on poly(L-lysine)-agarose. Two forms of this soluble mitochondrial protamine kinase were separated by chromatography on protamine-agarose. Both forms were purified about 80,000-fold to apparent homogeneity. Both forms of the protamine kinase consist of a single polypeptide chain with an apparent Mr approximately 45,000. Both enzyme forms underwent autophosphorylation without significant effect on activity, and both forms exhibited identical substrate specificities. The protamine kinase showed little activity toward branched-chain alpha-keto acid dehydrogenase (less than 3%), and it was essentially inactive (less than 0.1%) with pyruvate dehydrogenase, casein, and ovalbumin. The enzyme was active with histone H1 and with bovine serum albumin. Protamine kinase activity was unaffected by heparin (up to 100 micrograms/ml), by the protein inhibitor of cyclic AMP-dependent protein kinase, by Ca2+ and calmodulin, and by monoclonal antibody to the catalytic domain of protein kinase C from rat brain. The casein kinase was activated in the presence of spermine or by chromatography of the extract on DEAE-cellulose or poly(L-lysine)-agarose. The enzyme was purified about 80,000-fold to apparent homogeneity. It exhibited an apparent Mr 130,000 as determined by gel-permeation chromatography on Sephacryl S-300 in the presence of 0.5 M NaCl. Two subunits, with apparent Mr's 36,000 (alpha) and 28,000 (beta) were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The kinase underwent autophosphorylation of its beta-subunit, without significant effect on activity. Casein kinase activity was inhibited 50% by 1.5 micrograms/ml of heparin. Spermine (1.0 mM) stimulated activity of the purified kinase two- to three-fold at 1.5 mM Mg2+. Half-maximal stimulation occurred at 0.1 mM spermine. The kinase utilized both ATP and GTP as substrates. The casein kinase showed little activity (less than 1%) toward pyruvate dehydrogenase and branched-chain alpha-keto acid dehydrogenase from kidney mitochondria, and the kinase was essentially inactive with glycogen synthase a. The properties of this soluble mitochondrial kinase indicate that it is a type II casein kinase.
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PMID:Purification and properties of a protamine kinase and a type II casein kinase from bovine kidney mitochondria. 283 10

In recent years, two protein-tyrosine kinase activities, phosphorylating tyrosine residues on the transmembrane band-3 protein, have been isolated from human erythrocyte membranes and partially characterized by different laboratories, i.e. one extracted by non-ionic detergent (Triton X-100 or Nonidet P-40), the other solubilized by 0.25 M NaCl from the detergent-insoluble residue. The present paper shows that these two membrane-associated Tyr-protein kinases purified, in the presence of bovine serum albumin, by phosphocellulose chromatography followed by heparin-Sepharose chromatography, have the same apparent molecular mass (36 kDa) determined by Ultrogel Ac44 filtration. Moreover, both Tyr-protein kinases exhibit several identical properties, including Km values for band 3, the random acidic copolymer poly(Glu,Tyr)4:1 and angiotensin II, pH dependence, response to Mn2+ and Mg2+, response to NaCl and 2,3-bisphosphoglycerate. All these properties are identical or very similar to those exhibited by the Tyr-protein kinase previously isolated by us from human erythrocyte cytosol. These results suggest that the two membrane-associated and the cytosolic Tyr-protein kinase activities are mediated by the same enzyme, distributed between the cytosol and the membrane structures.
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PMID:Comparative characterization of membrane-associated and cytosolic Tyr-protein kinases in human erythrocytes. 292 Jul 26

Human erythrocyte casein kinase A, previously identified as a seryl, threonyl kinase, was found also to catalyze the phosphorylation of protein tyrosine. Phosphorylation of tyrosyl residues was detected in angiotensin-II and in several tyrosine containing synthetic peptides. In addition, phosphorylation on tyrosyl residues was also observed in alkylated bovine serum albumin and in band 3 and ankyrin purified from human erythrocyte membranes. The identification of phosphotyrosine was conducted using two-dimensional thin layer electrophoresis at pH 1.9 and 3.5 after acid hydrolysis of the phosphoproteins. It should be noted, however, that the major phosphorylation sites in band 3 and ankyrin catalyzed by casein kinase A were seryl and threonyl residues.
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PMID:Phosphorylation of protein tyrosine by human erythrocyte casein kinase A. 294 63

We have studied the expression of the protein kinase activity of NCP98, the c-fps gene product, in several hemopoietic tissues of chickens as a function of the developmental stage of these organs. We found that in bone marrow, spleen, and bursa, maximum NCP98 kinase activity on a per-cell basis correlates with the peak of granulopoiesis in these organs. Furthermore, in a bovine serum albumin density gradient fractionation of bone marrow cells, granulocytic cells appeared to account for most of the NCP98 kinase activity. No correlation was found between the distribution of erythrocytic, lymphocytic, or thrombocytic cells and the distribution of the expression of NCP98 kinase activity. However, NCP98 protein and kinase activity were 10-fold higher in macrophages than in bone marrow. In addition, depletion by complement-mediated lysis of erythrocytic cells in bone marrow did not significantly reduce the total recovery of NCP98 kinase activity. These results argue for the specific expression of the c-fps gene product in granulocytic cells and macrophages.
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PMID:Preferential expression of the c-fps protein in chicken macrophages and granulocytic cells. 298 74

Bovine serum albumin (BSA) was phosphorylated by the catalytic subunit of cAMP-dependent protein kinase under general protein phosphorylation conditions. The optimal pH for this phosphorylation was 9.0. The K0.5 (the concentration required for 50% of maximal phosphorylation) for BSA at pH 7.5 was 15 microM. One mole of phosphate was incorporated per mole of BSA, and only one phosphopeptide fragment was obtained after extensive proteolysis with trypsin. BSA phosphorylation required dithiothreitol or GSH, but GSH was only one-fiftieth as effective as dithiothreitol. GSSG counteracted the effect of dithiothreitol and GSH. Phosphorylation increased in a time-dependent and dithiothreitol concentration-dependent manner when BSA was preincubated with dithiothreitol. The increase in the incorporation of 32P correlated with the appearance of up to six free sulfhydryl groups. The effect of dithiothreitol on BSA appeared reversible, since reoxidation of reduced BSA decreased its susceptibility to phosphorylation. These experiments showed that this in vitro phosphorylation is dependent on the sulfhydryl-disulfide state of BSA. The possible implications of the sulfhydryl-disulfide state of proteins in the regulation of phosphorylation are discussed.
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PMID:Effect of sulfhydryl-disulfide state on protein phosphorylation: phosphorylation of bovine serum albumin. 298 43

Ca2+-activated, phospholipid-dependent protein kinase (protein kinase C) is widely distributed in mammalian tissues. Accumulating evidence has revealed that protein kinase C as well as cAMP-dependent protein kinase plays important roles in various cellular functions. The purpose of this study is to examine the effect of bilirubin on protein kinase C and cAMP-dependent protein kinase activity in a cell-free system as a cause of bilirubin toxicity to the central nervous system. Bilirubin inhibited protein kinase C activity in a dose-dependent manner. This effect was markedly diminished by the addition of human serum albumin at a molar ratio of bilirubin to albumin of less than 1.0. Kinetic analysis revealed that bilirubin did not compete with phospholipid, diacylglycerol, or calcium. Bilirubin also inhibited cAMP-dependent protein kinase, but did not compete with cAMP. The inhibitory effect of bilirubin on protein kinase C seems to be irreversible because removal of bilirubin by Sephadex G-25 column chromatography did not restore the protein kinase C activity. Observations reported herein suggest that bilirubin, especially in its free form, induces an irreversible change to the catalytically active site of protein kinase C.
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PMID:Mode of inhibitory action of bilirubin on protein kinase C. 298 61

In a tumor cell line of the mouse anterior pituitary (AtT-20/D16-16) consisting of a homogeneous population of corticotrophs, corticotropin-releasing factor (CRF) activates adenylate cyclase and cAMP-dependent protein kinase. In addition, CRF induces a rise in cytosolic calcium levels in AtT-20/D16-16 cells and stimulates adrenocorticotropin hormone release. To determine whether activation of cAMP-dependent protein kinase is essential for CRF to stimulate calcium mobilization and trigger adrenocorticotropin hormone release, an inhibitor of cAMP-dependent protein kinase was inserted into AtT-20/D16-16 cells using a liposome technique. In control cells, CRF, forskolin (a direct activator of adenylate cyclase) and potassium increased cytosolic calcium levels. Insertion of the protein kinase inhibitor into AtT-20/D16-16 cells greatly attenuated CRF and forskolin-stimulated calcium mobilization although it did not alter the rise in cytosolic calcium induced by potassium. Treatment of the cells with liposomes lacking protein kinase inhibitor (but containing an equivalent amount of bovine serum albumin) had no effect upon the calcium mobilization elicited by any of the agents tested. These results reveal an essential role for cAMP-dependent protein kinase in mediating CRF-stimulated calcium mobilization and suggest that its activation may be an essential molecular event for CRF to evoke adrenocorticotropin hormone secretion.
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PMID:Molecular mechanisms of corticotropin-releasing factor stimulation of calcium mobilization and adrenocorticotropin release from anterior pituitary tumor cells. 303 99

The interaction of cholecystokinin (CCK) C-terminal peptides with the protein inhibitor (PK-I) of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (A-PK) was studied by immunoprecipitation using anti-PK-I antibody. The binding of CCK-4 peptide to PK-I was shown to be specific; while CCK-4 enhanced precipitation of PK-I with antibody, it did not enhance precipitation of bovine serum albumin (BSA) by anti-BSA. The interaction of CCK-4 with PK-I is reversible and similar to that of urea but different from that of alkali. These results support the conclusion that CCK-C terminal peptides interact specifically with PK-I.
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PMID:Immunochemical evidence for interaction between cholecystokinin C-terminal peptides and the protein inhibitor of adenosine 3',5'-cyclic monophosphate dependent protein kinase in hog terminal bile ducts. 309 65

A polypeptide from a tryptic digest of bovine serum albumin potentiates glucose oxidation stimulated by insulin in isolated rat adipocytes. We studied whether this effect is related to a modification of the insulin receptor kinase. In a solubilized rat adipocytes receptor system, the peptide caused dose-dependent inhibition of the stimulation by insulin of phosphorylation of the 95,000 dalton subunit of insulin receptor. The peptide also inhibited stimulation by vanadate of tyrosine autophosphorylation of the beta subunit of the receptor, though it enhanced vanadate-stimulated glucose oxidation. During the phosphorylation reaction, no phosphorylated forms of the peptide could be detected. The peptide had no effect on dephosphorylation of the phosphorylated beta subunit of the insulin receptor. These results strongly suggest that the inhibition of phosphorylation by the peptide is due not to either simple substrate competition or activation of phosphoprotein phosphatase, but to specific inhibition of tyrosine-specific protein kinase.
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PMID:Inhibition of tyrosine autophosphorylation of the solubilized insulin receptor by an insulin-stimulating peptide derived from bovine serum albumin. 355 83


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