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)

Adenosine 3',5'-monophosphate (cAMP) dependent protein kinase (EC 2.7.1.37) catalyzes the phosphorylation of serine and threonine residues of a number of proteins according to the following chemical equation: ATP + protein leads to phosphoprotein + ADP. The DEAE-cellulose peak II holoenzyme from bovine brain, which is composed of regulatory and catalytic subunits, is resistant to ethoxyformic anhydride inactivation. After adding cAMP, the protein kinase becomes susceptible to ethoxyformic anhydride inhibition. Ethoxyformic anhydride (2mM) inhibits the enzyme 50% (5 min, pH 6.5, 30 degrees) in the presence of 10 muM cAMP, but less than 5% in its absence. The substrate, Mg2+-ATP, protects against inactivation suggesting that inhibition is associated with modification of the active site. Addition of regulatory subunit or Mg2+-ATP to the isolated catalytic subunit also prevents ethoxyformic anhydride inactivation. These results suggest that the regulatory subunit shields the active site of the catalytic subunit thereby inhibiting it. In contrast to the bovine brain or muscle DEAE-cellulose peak II holoenzyme, the bovine muscle peak I holoenzyme is susceptible to ethoxyformic anhydride inactivation in the absence of cAMP.
...
PMID:Bovine brain adenosine 3',5'-monophosphate dependent protein kinase. Mechanism of regulatory subunit inhibition of the catalytic subunit. 24 Apr 4

Cardiac microsomes contained an intrinsic adenosine 3',5'-monophosphate (cyclic AMP)-dependent protein kinase which stimulated phosphorylation of serine residue(s) of microsomal protein. The phosphorylated residues were associated with a microsomal protein component of 20,000 molecular weight as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Intrinsic phosphoprotein phosphatase activity of the microsomal membrane resulted in rapid dephosphorylation of these residues. Microsomes phosphorylated in the presence of cyclic AMP (10(-6) M) exhibited enhanced calcium uptake. We conclude that: 1) cardiac microsomes contain intrinsic cyclic AMP-dependent protein kinase(s) which phosphorylate a specific microsomal protein and phosphoprotein phosphatase(s) capable of dephosphorylating this protein, 2) phosphorylation of this protein enhances calcium uptake, 3) reversible phosphorylation of microsomal membrane may be an important mechanism for the regulation of calcium uptake of cardiac microsomes by cyclic AMP.
...
PMID:Characterization of soluble and microsomal adenosine 3',5'-monophosphate-dependent protein kinases from rabbit heart. 24 43

Evidence for phosphorylation of proteins by protein kinases has been found in Salmonella typhimurium despite previous indications that protein kinase action is absent in prokaryotes. At least four proteins have been found to be phosphorylated. Serine and threonine phosphates have been isolated from acid hydrolysates of these proteins after in vivo and in vitro labeling. The kinases do not phosphorylate histones, casein, or phosvitin. It would appear that phosphorylation as a regulatory control exists in prokaryotes.
...
PMID:Evidence for protein kinase activities in the prokaryote Salmonella typhimurium. 35 51

Pigeon heart microsomes contain three minor size protein kinase substrates of minimal molecular weights of 22 000, 15 000, and 11500, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When the microsomes were partially loaded with calcium oxalate and subjected to rate zonal and isopycnic centrifugations in sucrose density gradient columns, the 22 000 and the 15 000 dalton proteins settled in the heaviest fraction, which was composed mainly of vesicles of sarcoplasmic reticular membranes; the 11 500 dalton protein was concentrated in the lightest fractions, which consisted chiefly of vesicles of sarcolemmal origin. During incubation of the membrane fractions with Mg [gamma-32P]ATP significant amounts of 32P were incorporated into all these proteins. Incorporation of 32P into the 15 000 dalton protein was moderately and 32P incorporation into the 22 000 dalton protein was markedly enhanced in the presence of exogenous soluble cyclic AMP-dependent protein kinase and cyclic AMP. The phosphorylation of the three proteins was virtually unaffected by Ca2+ concentrations up to 0.1 mM and by ethyleneglycol-bis-(beta-aminoethyl-ether)-N,N'-tetraacetic acid in the absence of added Ca2+. Phosphorylation of the 22 000 and the 11 500 dalton proteins occurred mainly at serine residues. In the 15 000 dalton protein threonine residues were the main site of endogenous phosphorylation. Nearly equal amounts of [32P]-phosphate were incorporated into threonine and serine residues of this protein, when phosphorylation was supported by exogenous cyclic AMP-dependent protein kinase and cyclic AMP. The 15 000 dalton protein could be removed from its membrane attachment by extraction with an acidic chloroform/methanol mixture. This step opens the way for the purification of this membrane-bound protein kinase substrate.
...
PMID:Partial characterization of protein kinase-catalyzed phosphorylation of low molecular weight proteins in purified preparations of pigeon heart sarcolemma and sarcoplasmic reticulum. 36 42

Casein kinase from lactating bovine mammary gland catalyses the transfer of the terminal phosphoryl group of ATP to specific serine residues in dephosphorylated caseins. Best substrates for casein kinase are the dephosphorylated proteins (bovine alpha S1- and beta-caseins and pepsin), unphosphorylated human beta-casein and the dephosphorylated peptide (residues 1-25) from bovine beta-casein. Results obtained with bovine and human beta-caseins indicate that the two serines underlined in the cluster Ser-Leu-Ser-Ser-Ser are particularly susceptible to the action of casein kinase. Since a similar sequence is found in dephosphorylated alpha S1-casein, it is probable that serines in this region of alpha S1-casein are also phosphorylated. The results support the concept that certain serines in casein are particularly susceptible to phosphorylation by casein kinase.
...
PMID:Role of mammary casein kinase in the phosphorylation of milk proteins. 46 41

A procedure is described of the isolation of protein kinase, which phosphorylates isolated troponin T with a rate, 5--30 fold exceeding the phosphorylation rate of other substrates (phosvitine, caseine, protamine sulphate, H1, H2A, H2b, H3, H4 histones). Troponin T-specific protein kinase transfers 0.85--0.95 moles of P per 1 mol of dephosphorylated troponin T. It phosphorylates only N-terminal acetylated serine residue, i. e. the site of troponin T structure, which is normally phosphorylated, when the whole troponin complex is isolated from skeletal muscles. Protein kinase is incapable to phosphorylate N-terminal serine residue in a mixture of triptic peptides of troponon T.
...
PMID:[Skeletal muscle troponin and phosphorylation: a site of troponin T, that is phosphorylated by specific protein kinase]. 64 84

The phosphorylation of the single casein subfractions occurring when whole casein is incubated with [gamma-32P]ATP in the presence of two different rat liver 'casein kinases', both cyclic AMP-insensitive, has been studied. "Casein kinase TS", active on both threonine and serine residues of whole casein, was found to be active towards a minor protein fraction, running slightly ahead of beta-casein during gel electrophoresis, and accounting for most, if not all, of the [32P]Thr residues labeled in whole casein ("[32P]Thr-rich fraction"). The [32P]Ser residues labeled by this enzyme were recovered in an heterogeneous "[32P]Ser-rich fraction" including alphas1-casein together with minor alphas fractions, following alphas1-casein during gel electrophoresis. "Casein kinase S", on the other hand, active only towards serine residues of whole casein, is active almost exclusively towards the minor alphas casein fractions, with the exclusion of both the "[32P]Thr-rich fraction" and alphas1-casein itself. Therefore, of the major casein components, beta- and K-caseins apparently play a quite unimportant role in the overall phosphorylation of whole casein by both the protein kinases tested, while alphas1-casein itself, unlabeled by casein kinase S, accounts for no more than 20--30% of 32P incorporated in the presence of casein kinase TS.
...
PMID:Different susceptibility of whole casein components to enzymatic phosphorylation by two forms of rat liver 'casein kinase'. 66 79

1. The phosphorylation of troponin T from rabbit white sketetal muscle is catalysed by phosphorylase kinase, but not at a significant rate by bovine 3':5'-cyclic AMP-dependent protein kinase. 2. The amino acid sequences adjacent to the three major phosphorylation sites of troponin T were determined. 3. The serine in the N-terminal peptide (Asx,SerP, Glx)Glu-Val-Glu, is that phosphorylated (SerP, phosphoserine) when the troponin complex is isolated. 4. The other two sites of phosphorylation are located in the sequence Ala-Leu-(Ser, SerP)-Met-Gly-Ala-Asn-Tyr(Ser,SerP)Tyr. 5. When troponin T is phosphorylated in the presence of troponin C, the extent of phosphorylation at each site is considerably decreased. 6. CNBr fragments of troponin T are also phosphorylated by phosphorylase kinase, but the rate of phosphorylation at each site in the CNBr fragments is considerably slower than in the native protein. 7. From these studies it is suggested that troponin C interacts with troponin T in the region containing the two closely situated phosphorylation sites.
...
PMID:The phosphorylation sites of troponin T from white skeletal muscle and the effects of interaction with troponin C on their phosphorylation by phosphorylase kinase. 84 66

Synaptic-membrane fragments from ox cerebral cortex contain basal and cyclic AMP-stimulated protein kinase(s) that transfer 32P from [gamma-32P]ATP to hydroxyl groups of serine and threonine residues in membrane-protein substrates. In the present work, labelled membrane fragments were partitioned into soluble and insoluble fractions with Triton X-100, Nonidet P. 40, sodium deoxycholate and urea, and the distribution of 32P-labelled protein in the fractions was determined by polyacrylamide-gel electrophoresis and radioautography. A high percentage of phosphorylated protein sustrates remained insoluble, including those whose phosphorylation was most highly stimulated by cyclic AMP. Whole membrane fragments and samples prepared by detergent extraction were fractionated on Sepharose 6B columns in the presence of low concentrations of sodium dodecyl sulphate and pooled fractions were analysed by polyacrylamide-gel electrophoresis and radioautography. Phosphorylated proteins were fractionated on the basis of their molecular weight, but homogeneous protein was not obtained. The results are discussed in relation to the techniques used and the results obtained in other laboratories.
...
PMID:Phosphorylation of synaptic-membrane proteins from ox cerebral cortex in vitro. Preparation of fractions enriched in phosphorylated proteins by using extraction with detergents and urea, and gel filtration. 86 30

The action of phosphorylase kinase on synthetic peptides is reported. These peptides are variants of the amino acid sequence. Ser-Asp-Gln-Glu-Lys-Arg-Lys-Gln-Ile-Ser-Val-Arg-Gly-Leu, found in the natural substrate, phosphorylase b. The effects of size, the cluster of basic groups at the NH2-terminal side, the phosphorylatable seryl residue, the hydrophobic groups surrounding serine, and the arginyl function at the COOH-terminal side were tested and analyzed by evaluation of the kinetic parameters, Km and Vmax. The first 6 residues were found to be nonessential, but substitution of residues in the sequence. Lys-Gln-Ile-Ser-Val-Arg, had a large effect on phosphorylation. A comparison was made between the action of nonactivated and activated phosphorylase kinase on selected peptides and phosphorylase b. Various forms of phosphorylase b were tested as substrates for cyclic AMP-dependent protein kinase in the presence of effectors and salts. Although phosphorylase would not serve as a substrate for protein kinase, the aforementioned synthetic peptide of the phosphorylase b sequence would do so, indicating that the primary sequence surrounding the phosphorylatable serine did not block phosphorylation, which suggests that higher order structural features prohibit the phosphorylation.
...
PMID:Studies on the specificity of phosphorylase kinase using peptide substrates. 88 72


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

---