PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “PHOSPHORYLASE KINASE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1987

Subunit phosphorylation and activation of phosphorylase kinase in perfused rat hearts.

The potential correlations between phosphorylase kinase subunit phosphorylation and activation have been examined using 32P-perfused rat hearts exposed to a variety of hormonal stimuli. Phosphate incorporation was measured after isolation of the enzyme by immunoprecipitation from heart extracts. Time courses of catecholamine or glucagon treatment produced a rapid rise in both the activity and the beta subunit phosphorylation of the enzyme, and a slightly slower increase in alpha' subunit phosphorylation. For short durations of catecholamine stimulation, the ratio of phosphate in the alpha' versus beta subunit was dependent upon hormone dose. After removal of hormone, both inactivation and alpha' subunit dephosphorylation were fairly slow, while the beta subunit was dephosphorylated more rapidly. For all of the above conditions, activation correlated with both alpha' and beta subunit phosphorylation. The maximum level of phosphate incorporation observed in response to hormonal stimulation is estimated to be approximately 1.3-1.7 mol of [32P]phosphate/mol of (alpha' beta gamma delta)4, divided about equally between the alpha' and beta subunits. When hearts were treated with hormone either in the absence of added calcium or in the presence of a calcium channel blocker, the time courses of subunit phosphorylation and activation were similar to those seen with standard perfusion conditions, suggesting that if any Ca2+-dependent autophosphorylation of phosphorylase kinase were occurring it does not make a major contribution to the observed hormonal responses. The complicated relationships observed here between phosphorylase kinase subunit phosphorylation and activation for the most part provide physiological affirmation of the patterns observed in vitro, but they also show some possible differences of potential interest.

Animals↗
PubMed1980

Phosphorylase kinase phosphorylation of skeletal-muscle troponin T.

Rabbit skeletal-muscle troponin T was phosphorylated by a standard preparation of phosphorylase kinase [Cohen (1973) Eur. J. Biochem. 34, 1--14] and by fractions obtained after chromatography of phosphorylase kinase on phosphocellulose. The original preparation of phosphorylase kinase phosphorylated at least two sites, one of which was serine-1. The second and probably the third sites were presumably located in the peptide flanked by amino-acid residues 147 and 161 of troponin T. Fractions of phosphorylase kinase was adsorbed on phosphocellulose phosphorylated only the second site. Tightly adsorbed fractions possessed high troponin T kinase and phosvitin kinase activities and phosphorylated only serine-1 of troponin T. The results suggest that standard preparations of phosphorylase kinase are contaminated by troponin T kinase, which can phosphorylate serine-1 of troponin T.

Amino Acids↗
PubMed1991

Cleavage of phosphorylase kinase and calcium-free calmodulin by HIV-1 protease.

Phosphorylase kinase and calcium-free calmodulin are digested by human immunodeficiency virus-1 protease. In phosphorylase kinase, the alpha subunit is preferentially hydrolyzed at arg748-val749. The beta subunit is cleaved only slowly at leu678-pro679, and calmodulin, the integral delta subunit of phosphorylase kinase, is not cleaved at all. However, free calmodulin in the calcium-depleted form showed to be a good substrate for the protease. Here the cleavage occurs at phe65-pro66 and met71-met72. This fast hydrolysis of free calmodulin can be blocked by micromolar concentrations of Ca2+ or millimolar concentrations of Mg2+.

Amino Acid Sequence↗
PubMed1980

X-linked dominant inheritance of partial phosphorylase kinase deficiency in mice.

A new mouse strain, the V strain, with a partial deficiency of phosphorylase kinase has been established. The deficiency is caused by an X-linked dominant gene (PhKc). Muscle extracts of homozygous and heterozygous females and hemizygous males have about 25% of the activity found in extracts of normal (C3H/HeHan) mice. This dominant phosphorylase kinase deficiency of the new V strain is different from that of the I-strain mice with the X-linked recessive deficiency of skeletal muscle phosphorylase kinase. The muscle extracts of V-strain and normal mice contain the same phosphorylase phosphatase activity of about 1 U/mg. Heart and liver extracts from V mice contained about 50% and 66%, respectively, of the phosphorylase kinase activity compared to that found in the same organs from the normal mice. The glycogen content of the skeletal muscle of the V strain was normal, i.e., 0.9 mg/g. Phosphorylase kinase was purified from the skeletal muscle of the V strain by (a) hydrophobic chromatography on methylamine Sepharose, (b) ammonium sulfate precipitation, and (c) gel filtration of Sepharose 4B. The enzyme has a similar structure to the normal murine and rabbit skeletal muscle enzyme, except that the proportion of the subunits differs. The molar ratio of the subunits of the V strain mice is (alpha + alpha'):beta:gamma=0.54:1:1.169, in comparison with that of the rabbit (alpha + alpha'):beta:gamma=1.1:1.0:1.0 and that of normal murine enzyme 0.9:1.0:0.7.

Animals↗
PubMed1978

Phosphorylase kinase isoenzymes in deficient ICR/IAn mice.

ICR/IAn mice present a deficiency in phosphorylase kinase activity; the extent of this deficiency is less in some tissues [Lyon, S.B. Biochem. Genet. 4, 169--185 (1970)] than in skeletal muscle, where enzyme activity is 0.3% of normal [Cohen, P.T. W & Cohen, P. FEBS Lett. 29, 113--115 (1973)]. New-born mice of this strain were also reported (Lyon, 1970) to reveal a small amount of skeletal muscle enzyme activity. The properties of these residual phosphorylase kinases were compared to those of control C57 BL mice, with reference to control muscle and liver enzymes which were shown to be of different molecular species [Daegelen-Proux et al. Biochim. Biophys Acta, 452, 398--405 (1976)]. The properties investigated were the immunological reactivity against an antiserum raised against muscle phosphorylase kinase, the thermal stability and the Ca2+ dependency. The results suggest that the muscle enzyme from the new-born ICR/IAn mice and the heart enzyme from adult deficient mice are different to the muscle enzyme from adult normal mice, but they have properties in common with normal adult liver enzyme. These results lead to the conclusion that there exists in the muscle of I strain a "foetal form" of phosphorylase kinase, the activity of which decreases progressively after birth. Out work also confirmed the observations made by Cohen et al. [Eur. J. Biochem. 66, 347--356 (1976)] which showed that there is no evidence for the existence of a cross-reacting material in the muscle of adult deficient mice.

Aging↗
PubMed1990

Direct visualization of phosphorylase-phosphorylase kinase complexes by scanning tunneling and atomic force microscopy.

In skeletal muscle the activation of phosphorylase b is catalyzed by phosphorylase kinase. Both enzymes occur in vivo as part of a multienzyme complex. The two enzymes have been imaged by atomic force microscopy and the results compared to those previously found by scanning tunneling microscopy. Scanning tunneling microscopy and atomic force microscopy have been used to view complexes between the activating enzyme phosphorylase kinase and its substrate phosphorylase b. Changes in the size and shape of phosphorylase kinase were observed when it bound phosphorylase b.

Animals↗
PubMed1977

Activation of glycogen phosphorylase kinase by a calcium-activated, cyclic nucleotide-independent protein kinase system.

A protein kinase, which was produced from its proenzyme occurring in rat brain upon limited proteolysis by a Ca2+-dependent protease from the same tissue (Inoue, M., Kishimoto, A., Takai, Y., and Nishizlka, Y. (1977) J. Biol. Chem. 252, 7610-7616, was capable of phosphorylating alpha and beta subunits of rabbit skeletal muscle glycogen phosphorylase kinase, resulting in a marked enhancement of the enzymatic activity. This protein kinase was entirely independent of cyclic nucleotides and differed from the catalytic subunit of cyclic AMP-dependent protein kinase. The activation of phosphorylase kinase by this active protein kinase was not inhibited by a protein inhibitor of cyclic AMP-dependent protein kinase, nor by ethylene glycol bis(beta-aminoethyl ether)N',N'-tetraacetic acid, which prevented autophosphorylation of phosphorylase kinase. The proenzyme was distinguishable from cyclic nucleotide-dependent protein kinases, since it did not bind cyclic AMP and cyclic GMP, and was inactive in the phosphorylation and activation of phosphorylase kinase both in the presence and absence of these cyclic nucleotides. Neither the protein kinase nor its proenzyme showed phosphorylase kinase activity. Available evidence indicates that the Ca2+-activated, cyclic nucleotide-independent protein kinase system as well as cyclic AMP-dependent protein kinase shows an ability to stimulate glycogen breakdown as far as tested in vitro.

Animals↗
PubMed1980

Glycogen synthase from rabbit skeletal muscle. Amino acid sequence at the sites phosphorylated by glycogen synthase kinase-3, and extension of the N-terminal sequence containing the site phosphorylated by phosphorylase kinase.

Glycogen synthase kinase-3 phosphorylates three serine residues on glycogen synthase (sites 3a, 3b and 3c) which are all located in the same nine-amino-acid segment of the polypeptide chain. The sequence in this region is: Arg-Tyr-Pro-Arg-Pro-Ala-Ser(P)-Val-Pro-Pro-Ser(P)-Pro-Ser-Leu-Ser(P)-Arg-. These serine residues are distinct from the sites phosphorylated preferentially by cyclic-AMP-dependent protein kinase (sites 1a and 1b) and phosphorylase kinase (site 2). The N-terminal sequence of glycogen synthase containing the serine residue phosphorylated by phosphorylase kinase has been extended. The sequence in this region is: Pro-Leu-Ser-Arg-Thr-Leu-Ser(P)-Val-Ser-Ser-Leu-Pro-Gly-Leu-Glu-Asp-Trp-Glu-Asp- Glu-Phe-Asp-Leu-Glu-Asn-Ser-Val-Leu-Phe-(Asx2,Glx2,Ala2,Val2,Lys)-. The similarity to the N-terminal sequence of phosphorylase is confined to the immediate vicinity of the phosphorylation site (residues 4--15). The relationship of glycogen synthase kinase-3 to glycogen synthase kinases that have been described by other laboratories is discussed.

Amino Acid Sequence↗
PubMed1984

The Mg2+ requirements of nonactivated and activated rat liver phosphorylase kinase. Inhibition of the activated form by free Mg2+.

Incubation of rat liver phosphorylase kinase in the presence of MgATP results in a time-dependent increase in activity, i.e., activation. Determination of the magnitude of activation depends, in large part, on the relative concentrations of Mg2+ and ATP used in the phosphorylase kinase activity assay, such that as the Mg2+ to ATP ratio increases less activation is detectable. Prior to activation, maximal activity of nonactivated phosphorylase kinase requires a 2-3-fold molar excess of Mg2+ (i.e., free Mg2+) over ATP. MgATP-dependent activation of the enzyme results in an alteration in the free Mg2+ requirement such that the activity of the activated enzyme is sharply inhibited by the free cation. Inhibition by free Mg2+ of the activated enzyme is rapidly reversed by removal of free Mg2+ but is not affected by addition of Ca2+. Both nonactivated and activated forms of the enzyme appear to be inhibited by free ATP4-. The results show that the use of high concentrations of free Mg2+ in the phosphorylase kinase activity assay can blunt or completely obscure changes in enzyme activity following activation of the enzyme.

Adenosine Triphosphate↗
PubMed1988

The ATP-binding site in gamma subunit of phosphorylase kinase.

To reveal the structure of the ATP-binding site(s) in rabbit muscle phosphorylase kinase, we modified the enzyme with adenosine polyphosphopyridoxals. Adenosine tri- and tetraphosphopyridoxals at micromolar concentrations effectively inactivated the enzyme in a time-dependent manner. Inactivation of the enzyme was accelerated by the addition of Ca2+ and Mg2+. Protection from inactivation was afforded by adenylyl beta,gamma-imidodiphosphate and ADP. In reversible inhibition kinetics, adenosine polyphosphopyridoxals as well as their reduced compounds (adenosine polyphosphopyridoxines) competed with ATP. These results suggest that adenosine polyphosphopyridoxals bind to the ATP-binding site(s) in phosphorylase kinase. When phosphorylase kinase was incubated with adenosine triphosphopyridoxal in the presence of Ca2+ and Mg2+, incorporation of the label into alpha, beta, and gamma subunits was observed. In the absence of both cations, larger amounts of the label were incorporated into all the subunits. Structural study on adenosine triphosphopyridoxal-modified sites in the gamma subunit (having a catalytic site) revealed that Lys-151 is mainly labeled. Based on the results of the present and other studies, it is suggested that the site around Lys-151 is involved in recognition of the substrate protein.

Adenosine Triphosphate↗
PubMed1985

Inhibition of phosphorylase kinase, and tyrosine protein kinase activities by quercetin.

Quercetin, a naturally occurring bioflavonoid inhibited the activities of phosphorylase kinase and a partially purified tyrosine protein kinase from rat lung. The inhibition was rapid and concentration dependent. Quercetin at 100 microM inhibited the activities of phosphorylase kinase and tyrosine protein kinase by about 95 and 80-90 percent respectively. ATP reversed the quercetin mediated inhibition of tyrosine protein kinase but not of phosphorylase kinase. These data suggest that quercetin has differential effect on different protein kinase activities and it may be used as a tool to probe the role of various protein kinases in cell function.

Adenosine Triphosphate↗
PubMed2006

Interaction of phosphorylase kinase from rabbit skeletal muscle with flavin adenine dinucleotide.

The interaction of flavin adenine dinucleotide (FAD) with rabbit skeletal muscle phosphorylase kinase has been studied. Direct evidence of binding of phosphorylase kinase with FAD has been obtained using analytical ultracentrifugation. It has been shown that FAD prevents the formation of the enzyme-glycogen complex, but exerts practically no effect on the phosphorylase kinase activity. The dependence of the relative rate of phosphorylase kinase-glycogen complex formation on the concentration of FAD has cooperative character (the Hill coefficient is 1.3). Under crowding conditions in the presence of 1 M trimethylamine-N-oxide (TMAO), FAD has an inhibitory effect on self-association of phosphorylase kinase. The data suggest that the complex of glycogen metabolism enzymes in protein-glycogen particles may function as a flavin depot in skeletal muscle.

Animals↗
PubMed2002

A Ca(2+)-dependent global conformational change in the 3D structure of phosphorylase kinase obtained from electron microscopy.

Phosphorylase kinase (PhK), a Ca(2+)-dependent regulatory enzyme of the glycogenolytic cascade in skeletal muscle, is a 1.3 MDa hexadecameric oligomer comprising four copies of four distinct subunits, termed alpha, beta, gamma, and delta, the last being endogenous calmodulin. The structures of both nonactivated and Ca(2+)-activated PhK were determined to elucidate Ca(2+)-induced structural changes associated with PhK's activation. Reconstructions of both conformers of the kinase, each including over 11,000 particles, yielded bridged, bilobal structures with resolutions estimated by Fourier shell correlation at 24 A using a 0.5 correlation cutoff, or at 18 A by the 3sigma (corrected for D(2) symmetry) threshold curve. Extensive Ca(2+)-induced structural changes were observed in regions encompassing both the lobes and bridges, consistent with changes in subunit interactions upon activation. The relative placement of the alpha, beta, gamma, and delta subunits in the nonactivated three-dimensional structure, relying upon previous two-dimensional localizations, is in agreement with the known effects of Ca(2+) on subunit conformations and interactions in the PhK complex.

Animals↗
PubMed1990

Molecular genetics of phosphorylase kinase: cDNA cloning, chromosomal mapping and isoform structure.

A deficiency in phosphorylase kinase is responsible for several forms of glycogen storage disease which differ in heredity and affected tissues. This is so because phosphorylase kinase consists of four different subunits and has multiple tissue-specific isoforms. To elucidate the molecular basis of phosphorylase kinase deficiencies, the cDNAs encoding the subunits alpha and beta were cloned and sequenced. Each subunit was shown to be encoded by a single gene. The alpha subunit gene was mapped to chromosome Xq12-q13 and the beta subunit gene to chromosome 16q12-q13. Isoform cDNAs reveal differential mRNA splicing. Thus, the stage is set for the molecular characterization of the genes and their deficiency mutations.

Amino Acid Sequence↗
PubMed1981

Dephosphorylation of rabbit skeletal muscle phosphorylase kinase. Evidence against the operation of the "second-site phosphorylation" mechanism of regulation.

The dephosphorylation of rabbit skeletal muscle phosphorylase kinase was studied using two purified rabbit skeletal muscle protein phosphatases. The first enzyme (Mr = 32,000) corresponds to the form we have previously termed protein phosphatase C. Phosphorylase kinase was found to be rapidly dephosphorylated by this enzyme. The site of dephosphorylation was examined, and it was shown that this enzyme was relatively specific for the dephosphorylation of the beta-subunit phosphate, as compared to the alpha-subunit phosphate, of phosphorylase kinase. Phosphate release from the beta-subunit was approximately 100-fold faster than from the alpha-subunit. More importantly, dephosphorylation of the beta-subunit phosphate was not significantly affected by phosphorylation of the alpha-subunit. The dephosphorylation of phosphorylase kinase by a second low molecular weight protein phosphatase, Mr = 33,500, was also studied. The specific activity of this enzyme toward phosphorylase kinase was only a fraction of that exhibited by the Mr = 32,000 phosphatase. This enzyme removed phosphate from both the alpha- and beta-subunits but more rapidly (about 4-fold) from the alpha-subunit. With neither of these enzyme preparations was there any evidence for the regulation of beta-subunit dephosphorylation by phosphorylation of the alpha-subunit as proposed by Cohen and Antoniw ((1973) FEBS Lett. 34, 43-47).

Animals↗
PubMed1995

A continuous spectrophotometric assay for phosphorylase kinase.

A continuous spectrophotometric assay for the determination of the initial rate of the phosphorylase kinase catalyzed reaction at pH 7.0 is presented. The assay incorporates two coupling enzyme systems: (a) recombinant rabbit skeletal muscle type 1 protein phosphatase catalytic subunit which dephosphorylates the phosphorylase a product of the phosphorylase kinase reaction, and (b) the system of Webb (Proc. Natl. Acad. Sci. USA 89, 4884-4887, 1992), which uses purine nucleoside phosphorylase and its chromophoric substrate, 7-methyl-6-thioguanosine, for the quantitation of the resultant inorganic phosphate. The effects of reaction components on the enzyme activities were studied. The system was standardized and validated. The continuous coupled enzyme system was used for the kinetic analysis of nonactivated phosphorylase kinase at pH 7.0. Km and kcat values of 15.36 +/- 0.2 microM (phosphorylase b monomer) and 21 +/- 1.12 s-1, respectively, were determined.

Animals↗
PubMed1989

[Purification, quaternary structure and regulatory properties of phosphorylase kinase from pigeon skeletal muscle].

Using DEAE-Toyopearl column chromatography, a preparation of pigeon skeletal muscle phosphorylase kinase was obtained in a state approaching homogeneity. The molecular mass of the native enzyme (1320 kDa) and the subunit formula (alpha beta gamma delta)4 are similar to those of rabbit and chicken counterparts. Both red and white pigeon skeletal muscle isozymes contain the alpha'-subunit instead of alpha. Gradient SDS-PAGE electrophoresis revealed small but well-reproducible differences in the molecular masses of rabbit, chicken and pigeon muscle beta- and gamma-subunits. The activity ratio at pH 6.8/8.2 is 0.06-0.15 for different preparations of phosphorylase kinase b. The activity of pigeon muscle phosphorylase kinase b is Ca2+-dependent. The [Ca2+]0.5 value at pH 7.0 is 20 microM, which exceeds that for the chicken muscle enzyme by two orders of magnitude. In the presence of Ca2+, pigeon phosphorylase kinase b is activated 4-fold by saturating concentrations of calmodulin and troponin C. Pigeon muscle phosphorylase b is activated 3-5-fold during autophosphorylation or phosphorylation by the catalytic subunit of cAMP-dependent protein kinase.

Animals↗