Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.11 (AMPK)
 12,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The phosphorylation of sperm specific histone H1 in the sea urchin Strongylocentrotus purpuratus occurs both in vivo and in vitro on a single serine site in the sequence Arg-Lys-Gly-Ser(P)-Ser-Asn-Ala-Arg. This is a preferred sequence for cAMP-dependent protein kinase. The in vitro phosphorylation is completely dependent on cAMP and is inhibited by the peptide protein kinase inhibitor. The protein kinase inhibitor H-8 blocks the in vivo phosphorylation of H1 without damaging motility, the acrosome reaction or the ability of sperm to fuse with and activate eggs.
 ...
PMID:CAMP-dependent protein kinase of sea urchin sperm phosphorylates sperm histone H1 on a single site. 334 29

The phosphorylation of nuclear proteins of porcine brain cAMP-dependent protein kinase was studied. Some nuclear proteins after extraction from the nuclei served as substrates for protein kinase. Lysine-rich histones H1, H2a and H2b were found to accept phosphate during chromatin phosphorylation by cAMP-dependent protein kinase. Phosphorylation of intact nuclei revealed that in such a system only histone H1 is a substrate for cAMP-dependent protein kinase. In the presence of DNA the histones are phosphorylated by cAMP-dependent protein kinase in a different manner. It was concluded that DNA can determine the accessibility of protein substrates for the catalytic subunit of cAMP-dependent protein kinase.
 ...
PMID:[Nuclear proteins--substrates for cAMP-dependent protein kinase]. 366 52

The 31P NMR method was first applied to characterize in vivo phosphorylation of H1 and H5 in calf thymus and chicken erythrocytes as well as in vitro phosphorylation of H1 and H5 by cAMP-dependent protein kinase. The amino acid residues phosphorylated in vivo in the histones were exclusively serine residues, and the mole fraction of phosphoserine was estimated to be 0.34 and 0.27 per molecule of calf thymus H1 and chicken erythrocyte H5, respectively. Interestingly, chicken erythrocyte H1 was not phosphorylated in vivo. Three H1 subtypes from calf thymus H1 varied in the 31P NMR spectra, and the bisected fragments of calf thymus H1 and chicken erythrocyte H5 exhibited characteristic spectral patterns, indicating that there are considerable diversities of the degree of phosphorylation and phosphorylation sites in very-lysine-rich histones. Furthermore, it was found that the microenvironment of phosphoserine residues phosphorylated in vivo in calf thymus H1 and chicken erythrocyte H5 is quite distinct from that of phosphoserine residues phosphorylated in vitro by bovine heart cAMP-dependent protein kinase.
 ...
PMID:In vivo phosphorylation of histones H1 and H5 in calf thymus and chicken erythrocyte as studied by 31P nuclear magnetic resonance spectroscopy. 366 74

The nicotinic acetylcholine receptor is a substrate for cAMP-dependent protein kinase both in vitro and in vivo. Recently, it has been demonstrated that phosphorylation of the nicotinic receptor by this kinase increases its rate of rapid desensitization. We now report the identification of the cAMP-dependent phosphorylation sites on the gamma and delta subunits. Two-dimensional phosphopeptide mapping of the phosphorylated gamma and delta subunits, after limit proteolysis with thermolysin, indicated that each subunit is phosphorylated on a single site. Phosphoamino acid analysis of the 32P-labeled subunits demonstrates that phosphorylation had occurred exclusively on serine residues. Purified phosphorylated subunits were cleaved with cyanogen bromide and the resultant phosphopeptides were purified by reverse-phase high performance liquid chromatography. Shorter phosphopeptides, obtained by secondary digestion with trypsin, were purified and subjected to both automated gas-phase sequencing and manual Edman degradation. The results demonstrate that the gamma subunit was phosphorylated at Ser-353, contained within the sequence Arg-Arg-Ser(P)-Ser-Phe-Ile and that the delta subunit was phosphorylated at Ser-361, contained within the sequence Arg-Ser-Ser(P)-Ser-Val-Gay-Tyr-Ser-Lys. Determination of the sites phosphorylated within the structure of the gamma and delta subunits should contribute to the molecular characterization of the regulation of desensitization of the nicotinic acetylcholine receptor by protein phosphorylation.
 ...
PMID:Determination of the sites of cAMP-dependent phosphorylation on the nicotinic acetylcholine receptor. 368 Feb 73

Turkey gizzard smooth muscle myosin light chain kinase is a calmodulin-dependent enzyme containing 2 serine residues that can be phosphorylated by cAMP-dependent protein kinase. One of these sites can be phosphorylated only when calmodulin is not bound to the enzyme; the amino acid sequence around this site has been reported recently (Lukas, T. J., Burgess, W. H., Prendergast, F. G., Lau, W., and Watterson, D. M. (1986) Biochemistry 25, 1458-1464). Here we report the sequence around the site that is phosphorylated by cAMP-dependent protein kinase whether or not calmodulin is bound: Lys-Ala-Ser(P)-Gly-Ser-Ser-Pro-Thr-Ser-Pro-Ile-Asn-Ala-Asp-Lys-Val-Glu-A sn-Glu- . This sequence conforms to the previously defined criteria for substrates of cAMP-dependent protein kinase.
 ...
PMID:Smooth muscle myosin light chain kinase. Amino acid sequence at the site phosphorylated by adenosine cyclic 3',5'-phosphate-dependent protein kinase whether or not calmodulin is bound. 378 23

A major phosphopeptide labeled in vivo, was identified in nucleolar protein B23 (Mr/pI = 37,000/5.1) after tryptic digestion. This peptide was purified by high performance liquid chromatography using reverse-phase (C8 and C18) columns. The phosphopeptide contains 20 amino acids including 1 phosphoserine, 7 glutamic acids, and 4 aspartic acids. The amino acid sequence is: His-Leu-Val-Ala-Val-Glu-Glu-Asp-Ala-Glu-Ser(P)-Glu-Asp-Glu-Asp- Glu-Glu-Asp-Val-Lys. This amino acid sequence is similar to that of nucleolar phosphoprotein C23 (8 consecutive amino acids were identical), and to the regulatory subunit (RII) of cAMP-dependent protein kinase (7 consecutive amino acids were identical, which is phosphorylated by casein kinase II (Carmichael, D.F., Geahlen, R.L., Allen, S.M., and Krebs, E.G. (1982) J. Biol. Chem 257, 10440-10445). The regions near these phosphorylation sites are enriched with glutamic and aspartic acids, suggesting that this acidic amino acid cluster may be essential for kinase recognition.
 ...
PMID:Amino acid sequence of protein B23 phosphorylation site. 394 16

TLCK (N-alpha-tosyl-L-lysine chloromethyl ketone) inhibits protein kinase C whether or not the enzyme is under the regulation of Ca2+ and phospholipid. TLCK (IC50 = 1 mM) is a much more potent inhibitor of protein kinase C than TPCK (N-alpha-tosyl-L-phenylalanine chloromethyl ketone) (IC50 = 8 mM), suggesting that the lysyl moiety of TLCK may be specifically recognized by the active site of protein kinase C. These results extend the evidence that the active site of protein kinase C recognizes basic amino acids, and suggest that the active sites of protein kinase C and the cAMP-dependent protein kinase, which is also inhibited by TLCK and TPCK, are structurally related.
 ...
PMID:N-alpha-Tosyl-L-lysine chloromethyl ketone and N-alpha-tosyl-L-phenylalanine chloromethyl ketone inhibit protein kinase C. 404 11

Two murine monoclonal antibodies (H5 and B6) generated against bovine heart type II regulatory subunit of cAMP-dependent protein kinase were shown to cross-react equally well with the homologous subunit from porcine heart. The antibodies demonstrated specificity for only the type II regulatory subunit and showed negligible cross-reactivity with the type I regulatory subunit, the catalytic subunit, and cGMP-dependent protein kinase. Following limited proteolysis of type II regulatory subunit with chymotrypsin, the H5 monoclonal antibody was shown to cross-react with the Mr = 37,000 cAMP-binding domain corresponding to the COOH-terminal region of the polypeptide chain. To more specifically localize the antigenic sites, the porcine type II regulatory subunit was carboxymethylated and cleaved with cyanogen bromide. Both monoclonal antibodies cross-reacted with the NH2-terminal CNBr peptide, and this peptide demonstrated affinities similar to native bovine type II regulatory subunit in competitive displacement radioimmunoassays. Tryptic cleavage of this CNBr fragment destroyed all antigenicity for both monoclonal antibodies, whereas antigenicity was retained following chymotryptic digestion. A single major immunoreactive chymotryptic fragment that cross-reacted with H5 was isolated by gel filtration and reverse phase high performance liquid chromatography. this peptide retained the complete antigenic site and had the following sequence: Asn-Pro-Asp-Glu-Glu-Glu-Glu-Asp-Thr-Asp-Pro-Arg-Val-Ile-His-Pro-Lys-Thr-Asp-Gl n. This antigenic site was localized just beyond the major site of autophosphorylation, approximately a third of the distance from the NH2-terminal end of the polypeptide chain.
 ...
PMID:Monoclonal antibodies as structural probes of surface residues in the regulatory subunit of cAMP-dependent protein kinase II from porcine heart. 618 75

Purified lamb thymus high-mobility-group (HMG) proteins 1, 2, and 17 have been investigated as potential substrates for the Ca2+-phospholipid-dependent protein kinase and the cAMP-dependent protein kinase. HMG proteins 1, 2, and 17 are phosphorylated by the Ca2+-phospholipid-dependent protein kinase; the reactions are totally Ca2+ and lipid dependent and are not inhibited by the inhibitor protein of the cAMP-dependent protein kinase. HMG 17 is phosphorylated predominantly in a single seryl residue, Ser 24 in the sequence Gln-Arg-Arg-Ser 24-Ala-Arg-Leu-Ser 28-Ala-Lys, with the second seryl moiety, Ser 28, modified to a markedly lesser degree. HMGs 1 and 2 are also phosphorylated in only seryl residues but with each there are multiple phosphorylation sites. HMG 17, but not HMG 1 or 2, is also phosphorylated by the cAMP-dependent protein kinase with the site phosphorylated being the minor of the two phosphorylated by the Ca2+-phospholipid-dependent protein kinase; the Km for phosphorylation by the cAMP-dependent enzyme is 50-fold higher than that by the Ca2+-phospholipid-dependent enzyme. HMG 17 is an equally effective substrate for the Ca2+-phospholipid-dependent protein kinase either as the pure protein or bound to nucleosomes. Preliminary evidence has indicated that lamb thymus HMG 14 is also a substrate for the Ca2+-phospholipid-dependent enzyme. It is phosphorylated with a Km similar to that of HMG 17 (4-6 microM), and a comparison of tryptic peptides suggests that it is phosphorylated in a site that is homologous with Ser 24 of HMG 17 and distinct from the sites phosphorylated by the cAMP-dependent protein kinase.
 ...
PMID:Phosphorylation of high-mobility-group proteins by the calcium-phospholipid-dependent protein kinase and the cyclic AMP-dependent protein kinase. 623 36

The regulatory subunit of cAMP-dependent protein kinase II (RII) from porcine heart was modified specifically and covalently using the photoaffinity reagent, 8-azidoadenosine 3':5'-monophosphate (8-N3cAMP). In the presence of excess cAMP, the photo-dependent incorporation of 8-N3cAMP was abolished whereas excess AMP and ATP had no effect. A maximum incorporation of 0.5 mol of 8-N3cAMP was achieved/mol of regulatory subunit monomer (Mr = 55,000). This level of incorporation was obtained when the purified regulatory subunit was treated with urea prior to labeling to remove residual bound cAMP. When the regulatory subunit was labeled with radioactive 8-N3cAMP, cleaved with trypsin, and the tryptic peptides mapped in two dimensions, a single major radioactive peptide was observed. Chemical cleavage of the radioactively labeled RII with cyanogen bromide and subsequent chromatography on Sephadex G-50 also yielded a single major peak of radioactivity. The covalently modified cyanogen bromide peptide subsequently was purified to homogeneity using high performance liquid chromatography. Greater than 90% of the radioactivity that was incorporated into the regulatory subunit was recovered in this cyanogen bromide peptide which had the following sequence: Lys-Arg-Asn-Ile-Ser-His-Tyr (cAMP)-Glu-Glu-Cln-Leu-Val-Lys-Hse. When the Edman degradation of this peptide was carried out, the radioactivity derived from the 8-N3cAMP was released with the tyrosine residue at Step 7 identifying this residue as the specific site of attachment of the photoaffinity reagent.
 ...
PMID:Covalent modification of an adenosine 3':5'-monophosphate binding site of the regulatory subunit of cAMP-dependent protein kinase II with 8-azidoadenosine 3':5'-monophosphate. Identification of a single modified tyrosine residue. 625 Oct 58


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