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 results of kinetic studies are presented for two forms of soluble 3':5'-AMP-dependent protein kinase, obtained by DEAE-cellulose and hydroxyl apatite chromography. The pH optimum for both forms of the enzyme is shown to be 6.8-7.0; their activity is the highest at ionic strength of 0.023. Both forms of the enzyme at the above values of pH and ionic strength are thermoinactivated by the exponential law, their inactivation rate constants rise with temperature. Calcium ions in a concentration of 1.10(6)-2.10(-3) M have no effect on their activity.
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PMID:[Catalytic properties of soluble 3':5'-AMP-dependent protein kinase of rabbit myocardium]. 4 91

Urocaninase (EC 4.2.1.4.9) from rat liver homogenate has been purified, using protein precipitation at pH 4,8, ammonium sulfate fractionation, gel-filtration through Sephadex G-200 and chromatography on DEAE-cellulose. Upon DEAE-cellulose chromatography urocaninase is separated from the proteins possessing the activity of 3',5'-AMP-dependent protein kinase. The purified enzyme becomes activated after addition of ATP and exogenous protein kinase or one of the fractions resulting from DEAE-cellulose chromatography. Using [gamma-32P]ATP, it has been shown that such activation is accompanied by incorporation of at least one phosphate residue into the enzyme molecule. The mol. weight of urocaninase as determined by gel-filtration is about 110 000. The Km value for urocanate is 15 . 10(-6) M, the isoelectric point lies at 5,6. The mechanism of regulation of the urocaninase activity in rat liver is discussed.
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PMID:[Purification, properties and regulation of urocaninase from rat liver]. 4 82

We have studied the effect of protein phosphokinase (EC 2.7.1.37; ATP:protein phosphotransferase) and phosphoprotein phosphatase (EC 3.1.3.16; phosphoprotein phosphohydrolase) on reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) activity of Rous sarcoma virus. Protein kinase from Rous sarcoma virus-transformed chick embryo fibroblasts was purified by DEAE-cellulose chromatography, Sephadex gel filtration, and isoelectric focusing. Purified reverse transcriptase from Rouse sarcoma virus was preincubated with protein kinase and ATP under conditions allowing incorporation of phosphate into substrate protein. After the preincubation, reverse transcriptase activity was assayed in the presence of poly(rA).oligo(dT) as template. A 2- to 5-fold increase of reverse transcriptase activity was found after the preincubation of reverse transcriptase with protein kinase and ATP. Incubation of reverse transcriptase with heat-treated, inactive protein kinase and ATP had no effect on transcriptase activity. When the transcriptase preparation was incubated with protein kinase and [gamma-32P]ATP and subsequently purified by chromatography on phosphocellulose and Sephadex gel filtration, significant amounts of 32P-labeled proteins were found in the fractions exhibiting reverse transcriptase activity, suggesting 32P incorporation into transcriptase or transcriptase-associated proteins. A 20-60% decrease of reverse transcriptase activity was observed after incubation of reverse transcriptase with phosphatase. The results suggest that phosphorylative modification of reverse transcriptase may be critical in the regulation of reverse transcriptase-catalyzed DNA synthesis.
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PMID:Protein kinase and its regulatory effect on reverse transcriptase activity of Rous sarcoma virus. 5 72

Immunization of guinea pigs with bovine cardiac cAMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) resulted in the development of precipitating antibodies to the cAMP-binding subunit of the enzyme. Both the phosphorylated and nonphosphorylated cAMP-binding protein of the protein kinase reacted with the antiserum. A radioimmunoassay was developed that detects 10 ng of holoenzyme and permits measurement of enzyme concentrations in bovine cardiac muscle. Bovine liver, kidney, brain, and skeletal muscle contain protein kinases which are immunologically identical to those found in bovine cardiac muscle. However, the proportion of immuno-reactive enzyme activity differed for each tissue. All of the immunologically nonreactive enzyme in skeletal muscle and heart was separable from immunoreactive enzyme by chromatography on DEAE-cellulose. Rat tissues and pig heart contained protein kinase activity that crossreacted immunologically in a nonparallel fashion with bovine cardiac enzyme. These results indicate that cAMP-dependent protein kinases within and between species are immunologically heterogeneous.
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PMID:Radioimmunoassay of bovine heart protein kinase. 5 18

The structural polypeptides of purified viper range in molecular weight from 11,000 to 97,000 daltons and consist of 3 major and about 13 minor polypeptides. The virus contains both protein kinase and reverse transcriptase activities. Several of the structural polypeptides are phosphorylated in vitro by the virus-associated protein kinase. However, most (possibly all) of the viral structural polypeptides are not phosphorylated in vivo. DeoxyATP is as efficient as ATP in donating phosphate for in vitro phosphorylation of viral proteins. In vitro protein phosphorylation always precedes transcription and the virus-associated protein kinase and reverse transcriptase activities can be partially separated by sedimentation in a sucrose gradient.
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PMID:Structural and enzymatic characterization of viper C-type virus. 5 28

Activity of RNA-dependent DNA polymerase (RDDP) from avian myeloblastosis virus (AMV), either in purified form or in virus lysates, was increased by phosphorylation. Stability of RDDP in lysates buffered with phosphate was much greater (no loss of activity in 48 hours at 4 degrees) than that in lysates buffered with Tris-Cl (76% loss). Activity lost in the Tris-buffered extracts was completely restored by phosphorylation. The findings suggested that AMV RDDP activity is influenced by the degree of phosphorylation of the enzyme or enzyme-associated proteins and that this chemical modification is mediated by protein phosphokinase and phosphoprotein phosphatase present in crude extracts of purified AMV. Application of these results provided the basis of procedures whereby RDDP can be recovered in significantly higher yield and purity than formerly.
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PMID:Influence of phosphate on activity and stability of reverse transcriptase from avian myeloblastosis virus. 6 81

A protein kinase associated with purified virions of avian myeloblastosis virus, BAI strain A, was highly purified by ion-exchange chromatography and gel filtration. On the basis of molecular sieving on Sephadex G-200, the enzyme protein appeared to have a molecular weight of about 50,000 to 60,000; disc gel electrophoresis in sodium dodecyl sulfate-acrylamide gels revealed the presence of at least two polypeptide chains; and isoelectric focusing on acrylamide gels revealed two protein bands with activity. Of the nonviral proteins used as phosphate acceptors, the greatest rate of phosphorylation was obtained with alpha-casein. Potential physiological substrates for this activity included specific virion polypeptide of avian myeloblastosis virus. One of the virion polypeptides found in association with reverse transcriptase activity from avian myeloblastosis virus accepted more phosphate than any of nonviral or viral polypeptides examined on the basis of nanomoles of 32P incorporated per milligram of protein.
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PMID:Protein kinase and phosphoproteins of avian myeloblastosis virus. 6 29

Some physiologic aspects of the mobilization and fate of free fatty acids are reviewed. The molecular mechanism of the activation of hormone-sensitive lipase in adipose tissue is then discussed. Recent evidence established that hormone-sensitive lipase, concerned with fat mobilization, is both functionally and immunochemically distinct from lipoprotein lipase, concerned with uptake of plasma triglycerides. Lipoprotein lipase activity is not altered by cyclic AMP-dependent protein kinase. The latter enzyme enhances not only triglyceride hydrolase but also monoglyceride, diglyceride and cholesterol ester hydrolase activities in chicken adipose tissue. Finally, it is shown that the activation of all four acyl hydrolases is reversible, the deactivation being magnesium-dependent. Protein phosphatase fractions from heart and liver active against phosphorylase a can reversibly deactivate adipose tissue hormone-sensitive lipase, implying a low degree of substrate specificity for lipase phosphatase.
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PMID:Hormone-sensitive lipase of adipose tissue. 6 71

Activatable cholesterol esterase and triacylglycerol lipase of rat adrenal were 58-69% recovered in the 100 000 X g supernatant fraction. Activatable triacylglycerol lipase activity was differentiated from the activity of acid lipase and lipoprotein lipase also found in this fraction. Cholesterol esterase was activated 39.7 +/- 13.6% (S.D.) and triacylglycerol lipase 11.9 +/- 2.9% in a reaction dependent on ATP, cyclic AMP, and protein kinase. The two activities were shown by differential inhibition by an organophosphate, and by partial separation on salting out, to be largely due to separate enzymes. The two enzymes bound tightly to substrate emulsions with quantitatively similar distribution between competing emulsions, suggesting concerted binding. Coinciding gel filtration patterns reinforced, The hypothesis of a lipase complex. Cholesterol esterase comprised a major component of higher apparent Km for substrate and molecular weight 3-10(5)-6-10(5) by gel filtration and a minor component of lower apparent Km and heterogeneous molecular weight above 1 million, which was found mostly in complex and lipid.
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PMID:Activatable cholesterol esterase and triacylglycerol lipase activities of rat adrenal and their relationship. 6 45

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


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