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 541 records · Page 30Linked to original sources
PubMed1980

Morphochemical investigations of the liver and biochemical studies of the blood of guinea pigs in anaphylactic shock.

The experimental investigations have been carried out on 116 guinea pigs divided in two groups: the experimental and control group. The animals of the experimental group were sensitized with a 25% egg white suspension in 0.86% conc. of NaCl applied subcutaneously. After 21 days the same animals were exposed to the action of the same antigen in aerosol according to the method of Gerszanowicz, [16]. It has been shown, that in anaphylactic shock (acute and chronic) the damage of the lysosomal membranes in hepatocytes appeared which may be the cause of liberation among others also of acid phosphatase from the liver into the blood. Histochemically it was found a low phosphorylase and glucose-6-phosphatase activity, which was the basis of the assumption, that in anaphylactic shock we have to do with an enzymatic block--phosphorylase kinase--phosphorylase and inhibition of the enzymatic activity of glucose-6-phosphatase in the liver of guinea pigs. The comparison of the histochemical and biochemical results concerned with the amount of lipids, glycogen and nucleic acids in the liver revealed that the increasing amount of lipids is paralleled by decrease of glycogen. Among nucleic acids a growing level of ribonucleic acid was found while the level of the desoxyribonucleic acid remained stable.

Acid Phosphatase↗
PubMed1980

[Regulation of cellular functions of protein phosphorylation (author's transl)].

The biochemical mechanisms involved in the regulation of cellular functions by intracellular signals, such as calcium, cyclic AMP and cyclic GMP, are described briefly. Each cyclic nucleotide regulated diverse cellular functions by activating a specific protein kinase. Calcium, on the other hand, has several intracellular receptors, i. e., troponin-C, calmodulin and others, which may be present together in the same cell. In the presence of calcium, calmodulin activates a variety of enzymes including protein kinases, phosphorylase kinase and myosin light chain kinase. The specificity of hormonal effects in different tissues depends not only on the presence of the specific intracellular receptor system for each intracellular signal but also on the presence of specific isoenzymic forms of important regulatory enzymes, whose activity may or may not be regulated by phosphorylation and dephosphorylation.

Calcium↗
PubMed1983

Tyrosine protein kinase activity during embryogenesis.

The activity of tyrosine-specific protein kinase was estimated during early embryonic development of the sea urchin, Strongylocentrotus purpuratus, using the synthetic peptide Leu-Ile-Glu-Asp-Ala-Glu-Tyr-Ala-Ala-Arg-Arg-Arg-Gly as a probe. The peptide was not phosphorylated by the purified cyclic AMP-dependent protein kinase, phosphorylase kinase, glycogen synthase kinase 3, or casein kinase 2 but was phosphorylated by the purified epidermal growth factor-receptor kinase from A-431 cells. The sea urchin tyrosine protein kinase activity was determined in a particulate fraction (17,000 x g pellet) and in a membrane fraction obtained after discontinuous sucrose gradient centrifugation; these fractions contained higher specific activities of the kinase than the cytosolic or nuclear fractions. Unfertilized eggs had very low tyrosine protein kinase activity (0.22 pmol of peptide phosphorylated per mg of protein/min) in the particulate fraction, but the activity increased 2.5-fold by 1 h after fertilization and almost 20-fold by the gastrula stage. The enzyme activity of the membrane fraction increased similarly during this time period. The tyrosine protein kinase had an apparent Km of 8.9 mM for the peptide, and showed one-half-maximal velocity at about 35 microM MgATP. The phosphorylation of membrane fractions in vitro at different stages of embryonic development resulted in nine endogenous protein-staining bands (Mr = 26,000 to greater than 200,000; 10% Na dodecyl SO4 gels) which contained phosphotyrosine; some of the bands incorporated 32P differentially as a function of development. In the unfertilized egg membrane fraction, none of the protein-staining bands were shown to contain detectable 32P-tyrosine. Thus, fertilization results in increases in tyrosine-specific protein kinase(s) activity which continues to increase during early embryonic development; it is suggested that these protein kinases have a functional role during early development and differentiation.

Adenosine Triphosphate↗
PubMed1994

Calcium/calmodulin-dependent protein kinases.

Ca2+ is widely recognized as an essential intracellular second messenger in eukaryotic systems regulating processes such as muscle contraction, neurotransmitter release, gene expression and cell proliferation. The effects of Ca2+ are frequently mediated via interaction with calmodulin (CaM) and strong evidence indicates, in turn, that the effects of Ca2+/CaM are often achieved through the regulation of protein phosphorylation. A family of CaM-dependent protein kinases has been identified that includes: myosin light chain kinase, phosphorylase kinase, CaM kinase I, CaM kinase II, EF-2 kinase (CaM kinase III) and CaM kinase IV. The structure, regulation and function of this important family of second messenger-regulated protein kinases will be briefly reviewed.

Amino Acid Sequence↗
PubMed1985

Comparison of enzyme activities on glycogen metabolism in rabbit slow and fast muscles.

Activities of glycogen synthase (total) and branching enzyme in slow (soleus) muscle are higher than those in fast (vastus lateralis) muscle, while those of phosphorylase kinase (total), phosphorylase (total) and debranching enzyme are reversed. The active form ratio of glycogen synthase is higher in fast muscle, while those of phosphorylase kinase and phosphorylase are higher in slow muscle. Activities of cAMP-dependent protein kinase and protein phosphatase in slow muscle are higher than those in fast muscle. These results suggest that glycogen metabolizing enzymes in slow muscle, distinct from those in fast muscle, are regulated more strongly by cAMP-dependent protein kinase rather than by protein phosphatase.

Animals↗
PubMed1981

Phosphorylation of glycogen synthase in a homogenate of human polymorphonuclear leukocytes.

Glycogen synthase I in a homogenate of human polymorphonuclear leukocytes was phosphorylated under imitated physiological conditions utilizing the endogenous protein kinases. At subsequent steps of phosphorylation the 32P-labelled synthase was purified and characterized. Limited tryptic hydrolysis of the 32P-labelled synthase released four phosphopeptides (t-A, t-B, t-C, t-D) and subsequent chymotrypsinization of the trypsin resistant core released three phosphopeptides (c-A, c-B, c-C). One Pi/subunit was incorporated within 8-10 min and 2.2 Pi/subunit within 60 min increasing the Kc for Glc-6-P to 4-6 mM. The initial phosphorylation up to 0.8 Pi/subunit occurred mainly in peptide c-A and a linear relation between ratio of independence (RI) of glycogen synthase in the interval RI 0.85 to RI 0.05 and phosphorylation of this peptide of 0.5 Pi was observed. Phosphorylation of this peptide is responsible for the decrease in ratio of independence. From experiments with inhibitors and activators, the initial phosphorylation was found predominantly catalysed by the endogenous cAMP independent synthase kinase, however, the endogenous cAMP dependent protein kinase and phosphorylase kinase also phosphorylate endogenous glycogen synthase I to a minor degree. Circumstantial evidence for a Ca-dependent synthase kinase different from phosphorylase kinase is presented. The endogenous Glc-6-P dependent glycogen synthase occurring in a homogenate of leukocytes disrupted in the presence of NaF incorporated 1.07 Pi/subunit and Kc for Glc-6 was increased from 6-8 mM to 20 mM. From the present and previous experiments [7] a total of 8 major phosphorylatable sites have been defined, one on each of the peptides t-A, t-B, c-B, c-C and two on peptide c-A, which in addition may contain a third site for phosphorylase kinase. Assuming identical subunits, only 13 out of 32 sites are thus covalently modified at maximum phosphorylation. The operational defined synthase R (Kc for Glc-6-P 0.5 mM) and D (Kc for Glc-6-P 2-8 mM) activities correspond to synthase with about 0.8 Pi and 1.8-2.3 Pi/subunit, respectively.

Enzyme Activation↗
PubMed1976

Association of gylcogenolysis with cardiac sarcoplasmic reticulum.

Sarcoplasmic reticulum fragments isolated from dog cardiac muscle possess a calcium-accumulating system associated with a series of enzymes linked to glycogenolysis. These enzymes include: adenylate cyclase, cyclic AMP-dependent protein kinase, phosphorylase b kinase, phosphorylase (b/a, 30/1),"debrancher" enzyme, and glycogen (0.3 to 0.7 mg/mg of protein). The sarcoplasmic reticulum preparation produced glucose 1-phosphate and glucose from either endogenous or exogenous glycogen. Both the calcium-accumulating and glycogenolytic enzymes sediment in a single peak at 33% sucrose on a linear continous sucrose density gradient, and the complex remains intact throughout repeated washing. Glycogen particles appear to be associated with the sarcoplasmic reticulum in situ as well as in the isolated microsomal fraction. The sarcoplasmic reticulum-glycogenolytic complex, monitored by a linked enzyme spectrophotometric assay, shows several features: (a) activation of phosphorylase activity to peak rate occurs over a very rapid time course which cannot be duplicated using combinations of purified enzymes; (b) activation is inhibited by protein kinase inhibitor; (c) phosphorylase b functions as in the purified form with respect to AMP (Km, 0.3 mM); (d) in the presence of limiting amounts of glycogen, optimal phosphorylase b activity in the sarcoplasmic reticulum requires the presence of debrancher, and the activity is sensitive to inhibitors of that enzyme such as Tris, which suggests the possiblity that the enzymes bear a specific structual relationship to the glycogen present. Phosphorylase b leads to a activation in the sarcoplasmic reticulum was completely resistant to ethylene glycol bis(beta-aminoethyl either)-N,N'-tetraacetic acid (EGTA). Inhibition of calcium accumulation by or release of bound calcium from sarcoplasmic reticulum by X537A (RO 2-2985) did not alter the EGTA resistance. These results suggest that cardiac sarcoplasmic reticulum is a complex organelle containing functions that may be related to excitation-contraction coupling and intermediary metabolism.

Adenosine Monophosphate↗
PubMed1977

Inactivation and reactivation of liver phosphorylase b kinase.

When crude rat liver preparations were incubated at 30degrees C, a gradual loss of phosphorylase kinase (ATP:phosphorylase b phosphotransferase, EC 2.7.1.38) activity was observed. This inactivation was Mg2+ dependent and was partially inhibited by sodium fluoride. Addition of Mg2+ ATP to the liver preparations, at any time throughout the incubation, caused a reactivation of the phosphorylase kinase and this was accelerated by micromolar concentrations of cyclic AMP. The reactivation process could be completely abolished by the addition of a heat stable protein kinase inhibitor, implicating cyclic AMP dependent protein kinase in the activation reaction. Both the low and the high activity forms of the enzyme required micromolar quantities of Ca2+ for full activity (KA = 0.6 micronM). The two forms exhibit quite different pH dependencies and at the physiological pH of liver (pH 7.4) their activities differed by a factor of 5-10. Conversion of the lower activity form into the higher seems to affect only the V - Km for muscle phosphorylase b (EC 2.4.1.1) was about 1 mg/ml for both enzyme forms.

Adenosine Triphosphate↗
PubMed1977

Specificity of a protein phosphatase inhibitor from rabbit skeletal muscle.

A hear-stable protein, which is a specific inhibitor of protein phosphatase-III, was purified 700-fold from skeletal muscle by a procedure that involved heat-treatment at 95 degrees C, chromatography on DEAE-cellulose and gel filtration on Sephadex G-100. The final step completely resolved the protein phosphatase inhibitor from the protein inhibitor of cyclic AMP-dependent protein kinase. The phosphorylase phosphatase, beta-phosphorylase kinase phosphatase, glycogen synthase phosphatase-1 and glycogen synthase phosphatase-2 activities of protein phosphatase-III [Antoniw, J. F., Nimmo, H. G., Yeaman, S. J. & Cohen, P.(1977) Biochem.J. 162, 423-433] were inhibited in a very similar manner by the protein phosphatase inhibitor and at least 95% inhibition was observed at high concentrations of inhibitor. The two forms of protein phosphatase-III, termed IIIA and IIIB, were equally susceptible to the protein phosphatase inhibitor. The protein phosphatase inhibitor was at least 200 times less effective in inhibiting the activity of protein phosphatase-I and protein phosphatase-II. The high degree of specificity of the inhibitor for protein phosphatase-III was used to show that 90% of the phosphorylase phosphatase and glycogen synthase phosphatase activities measured in muscle extracts are catalysed by protein phosphatase-III. Protein phosphatase-III was tightly associated with the protein-glycogen complex that can be isolated from skeletal muscle, whereas the protein phosphatase inhibitor and protein phosphatase-II were not. The results provide further evidence that the enzyme that catalyses the dephosphorylation of the alpha-subunit of phosphorylase kinase (protein phosphatase-II) and the enzyme that catalyses the dephosphorylation of the beta-subunit of phosphorylase kinase (protein phosphatase-III) are distinct. The results suggest that the protein phosphatase inhibitor may be a useful probe for differentiating different classes of protein phosphatases in mammalian cells.

Animals↗
PubMed1976

Gene expression during the differentiation of myogenic cells of the L6 line.

The problem of the mechanistic relationship among the different phenotypic expressions in an established myogenic line was approached by blocking cell fusion at different developmental stages, by addition of cytochalasin B. The addition of the drug to cultures at the time when the first two myotubes appeared on the dish, blocked fusion, but did not affect DNA synthesis, expression of myosin, phosphorylase, phosphocreatine kinase, phosphorylase kinase or glycogen synthetase, nor the organization of the elements of the hexagonal lattice. It is concluded that cell fusion is not a prerequisite for the expression of the differentiated phenotype.

Cell Differentiation↗
PubMed1985

Selective effects of CAPP1-calmodulin on its target proteins.

Occupancy of one of the two phenothiazine-binding sites on calmodulin does not significantly decrease the affinity of calmodulin for its target proteins; however, it does affect the ability of calmodulin to activate some enzymes. Previously we demonstrated that a covalent adduct of calmodulin with one molecule of phenothiazine (CAPP1-calmodulin) is an antagonist for the calmodulin-dependent enzymes, cAMP phosphodiesterase and myosin kinase, and a partial agonist for calcineurin. We now show that CAPP1-calmodulin is a full agonist for glycogen synthase kinase and phosphorylase kinase. Unlike phenothiazines, CAPP1-calmodulin is specific for calmodulin-regulated proteins; it has no effect on protein kinase C. With the exception of phosphorylase kinase, occupancy of two phenothiazine-binding sites completely eliminates the ability of calmodulin to activate these proteins. Thus, the study of the interaction of CAPP1-calmodulin with calmodulin target proteins demonstrates that calmodulin interacts differently with different proteins. This is confirmed by studies of the effect of calmodulin fragments, 1-77 and 78-148, on calmodulin-regulated enzymes.

Animals↗
PubMed1978

Comparison of the mechanism of isoproterenol-stimulated glycogenolysis in skeletal muscle of normal and phosphorylase kinase-deficient mice (I strain).

Diaphragm extracts from mice with the phosphorylase kinase deficiency mutation (I strain) have only 3.7% of the phosphorylase kinase activity of muscle extracts of the control strain (C57BL). Nevertheless, previous studies have shown that isoproterenol-stimulated glycogenolysis in I strain diaphragm muscle at a rate 57% (average relative response at 10 isoproterenol concentrations) of that of C57BL (GROSS, S.R., MAYER, S.E. and LONGSHORE, M.A.: J. Pharmacol. Exp. Ther. 198: 523-538, 1976). The present studies were initiated to compare the mechanism of isoproterenol-stimulated glycogenolysis in I and C57BL diaphragms. Isoproterenol was found to stimulate phosphorylase b to a conversion with an EC50 of 8 nM in muscles from mice of either strain, and the maximum increase in phosphorylase alpha activity in I diaphragms was 23% of that in C57BL diaphragms. Moreover, the initial rate of increase in phosphorylase alpha activity in I diaphragms incubated with 40 nM isoproterenol was 24% of that in C57BL muscles. The isoproterenol-stimulated increases in cyclic AMP content in diaphragms of the two strains were the same. Incubation of I diaphragms with isoproterenol did not significantly increase the concentrations of AMP, IMP or inorganic phosphate, activators of phosphorylase beta activity, nor was there a decrease in ATP and glucose 6-phosphate content, allosteric inhibitors of phosphorylase beta activity. Thus, phosphorylase alpha formation is the principal, if not only, catalyst of isoproterenol-stimulated glycogenolysis in skeletal muscle of phosphorylase kinase-deficient mice, and no evidence was obtained indicating that allosteric regulation of phosphorylase beta activity is part of the mechanism.

Adenine Nucleotides↗
PubMed1988

The abundance of calmodulin mRNAs is regulated in phosphorylase kinase-deficient skeletal muscle.

In the I/Lyn mouse strain a mutation on the X chromosome results in a deficiency of the major calmodulin-regulated enzyme in skeletal muscle, phosphorylase kinase. Calmodulin has been identified as the delta-subunit of phosphorylase kinase, and it is estimated that approximately 40% of the total calmodulin in rabbit skeletal muscle is associated with the phosphorylase kinase hexadecamer (alpha, beta, gamma, delta)4. The absence of phosphorylase kinase in I/Lyn skeletal muscle results in a reduction in the total amount of calmodulin. The mechanisms affecting this reduction were investigated by comparing the abundance and heterogeneities in calmodulin mRNAs between normal and phosphorylase kinase-deficient skeletal muscles. The results demonstrate that in normal tissue there are four species of calmodulin mRNA distinguished by their molecular weight. All four of these species are present in the deficient tissue, and none of them are preferentially reduced. However, there is a 54% reduction in all four mRNAs as well as in calmodulin in the deficient skeletal muscle relative to normal skeletal muscle. These results indicate that the expression of calmodulin mRNAs is coordinated with the expression of its major enzyme target in skeletal muscle.

Amino Acid Sequence↗
PubMed1983

Calmodulin-dependent glycogen synthase kinase: identification in liver of normal and phosphorylase kinase-deficient rats.

We have purified a calmodulin-dependent glycogen synthase kinase from livers of normal and phosphorylase kinase-deficient (gsd/gsd) rats. No differences between normal and gsd/gsd rats were apparent in either (a) the ability of liver extracts to phosphorylate exogenous glycogen synthase in a Ca2+- and calmodulin-dependent manner or (b) the purification of the calmodulin-dependent synthase kinase. Although extracts from rat liver, when compared to rabbit liver extracts, had a significantly reduced ability to phosphorylate exogenous synthase, the calmodulin-dependent synthase kinase could be purified from rat liver using a protocol identical to that described for rabbit liver. Moreover, the synthase kinase purified from rat liver had properties very similar to those of the rabbit liver enzyme. The enzyme was completely dependent on calmodulin for activity against glycogen synthase, was unable to phosphorylate phosphorylase b, catalyzed the rapid incorporation of 0.4 mol phosphate/mol of glycogen synthase subunit, selectively phosphorylated sites 1b and 2 in the glycogen synthase molecule, had a Stokes' radius of about 70 A, and appeared to be composed of subunits of Mr 56,000 and 57,000. These observations led us to conclude that (1) calmodulin-dependent glycogen synthase kinase is distinct from other kinases previously described and (2) the rat liver kinase and the rabbit liver kinase are very similar enzymes.

Animals↗
PubMed1975

Pyridoxal phosphate-dependent conformational states of glycogen phosphorylase as probed by interconverting enzymes.

The interaction between pyridoxal 5'-phosphate and the convertible serine of glycogen phosphorylase has been investigated by using: specific interconverting enzymes, phosphorylase kinase and phosphorylase phosphatase; effectors, glucose and glucose 6-phosphate; and a protein kinase and trypsin. Both phosphorylase kinase and phosphorylase phosphatase utilized the native protein while having little influence on the apoprotein. Removal of a peptide containing the critical serine residue gave phosphorylase b' from which the pyridoxal 5'-phosphate in phosphorylase has an important effect on enzymic interconversion.

Apoenzymes↗
PubMed1975

The phosphorylation of troponin I from cardiac muscle.

1. Troponin I isolated from fresh cardiac muscle by affinity chromatography contains about 1.9 mol of covalently bound phosphate/mol. Similar preparations of white-skeletal-muscle troponin I contain about 0.5 mol of phosphate/mol. 2. A 3':5'-cyclic AMP-dependent protein kinase and a protein phosphatase are associated with troponin isolated from cardiac muscle. 3. Bovine cardiac 3':5'-cyclic AMP-dependent protein kinase catalyses the phosphorylation of cardiac troponin I 30 times faster than white-skeletal-muscle troponin I. 4. Troponin I is the only component of cardiac troponin phosphorylated at a significant rate by the endogenous or a bovine cardiac 3':5'-cyclic AMP-dependent protein kinase. 5. Phosphorylase kinase catalyses the phosphorylation of cardiac troponin I at similar or slightly faster rates than white-skeletal-muscle troponin I. 6. Troponin C inhibits the phosphorylation of cardiac and skeletal troponin I catalysed by phosphorylase kinase and the phosphorylation of white skeletal troponin I catalysed by 3':5'-cyclic AMP-dependent protein kinase; the phosphorylation of cardiac troponin I catalysed by the latter enzyme is not inhibited.

Animals↗
PubMed1975

Debranching enzyme from rabbit skeletal muscle. Purification, properties and physiological role.

Debranching enzyme was purified 150-fold from rabbit skeletal muscle by a three-step procedure which utilised ammonium sulphate precipitation, ion-exchange chromatography on DEAE-cellulose and "hydrophobic" chromatography on Sepharose-NH(CH2)4NH2. The preparation was completed within three days, and 200 mg enzyme was isolated from 1000 g muscle, which represented an overall yield of 60%. The preparation was homogeneous by the criteria of polyacrylamide gel electrophoresis and ultracentrifugal analysis. The sedimentation coefficient, s20,w, was 8.1 S. The amino acid composition was determined, and the absorption coefficient, A280 1%, measured refractometrically was 17.5. The subunit molecular weight determined by gel electrophoresis in the presence of sodium dodecyl sulphate was 166000 and this value was supported by sedimentation equilibrium in the presence of 6 M guanidinium chloride (1550oo). The molecular weight of the native enzyme measured by high-speed sedimentation equilibrium was 164000, showing that the debranching enzyme is a monomeric protein at the concentrations which exist in muscle (0.7 mg/ml). The results indicate that the two different enzyme activities which are associated with debranching enzyme, 1,4-glucan-4-glycosyltransferase and amylo-1,6-glucosidase, reside on the same polypeptide chain. Protein-glycogen particles isolated from skeletal muscle showed seven major protein-staining components by polyacrylamide gel electrophoresis, one of which was identified as debranching enzyme. ,our of the other components were the alpha and beta subunits of phosphorylase kinase, glycogen phosphorylase and glycogen synthetase. A new titrimetric assay for debranching enzyme was developed; it was used to demonstrate that the maximum potential activity of debranching enzyme is only 5--10% that of phosphorylase at the concentrations of the two enzymes in skeletal muscle. Since the activity of debranching enzyme is unaffected by every mechanism which leads to the activation of glycogen phosphorylase and phosphorylase kinase, the evidence suggests that the hormonal control of muscle glycogenolysis by adrenalin might be confined to a stimulation of rate of degradation of the outermost branches of glycogen.

Amino Acids↗