Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Protamine Kinase”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 721 records · Page 40Linked to original sources
PubMed1987

Non-requirement of calcium on protamine phosphorylation by calcium-activated, phospholipid-dependent protein kinase.

Phosphorylation of clupeine sulfate by purified rat brain calcium-activated, phospholipid-dependent protein kinase (protein kinase C) was studied. In the absence of Ca2+, phosphatidylserine and diolein markedly stimulated its phosphorylation. However Ca2+ did not stimulate but inhibit this phosphorylation about 30% in the presence of phospholipids. Random polymer (Arg, Ser) 3:1 and (Lys, Ser) 3:1 could be phosphorylated by protein kinase C. In the presence of phospholipids Ca2+ is not needed for the phosphorylation of polymer (Arg, Ser) 3:1, while Ca2+ is necessary for polymer (Lys, Ser) 3:1. Non-requirement of Ca2+ on clupeine phosphorylation by protein kinase C is briefly discussed.

Calcium↗
PubMed1983

Purification and properties of swine kidney phosphoprotein phosphatase.

Phosphoprotein phosphatase was purified from swine kidney by chromatography on DEAE-Sephadex A-50, Sephacryl S-200 and Sepharose 4B columns containing covalently bound hexanediamine and polylysine. The enzyme was purified more than 20000-fold and the homogeneous preparation had a specific activity of 2.8 micromol per min per mg of protein with saturating concentrations of 32P-histone as the substrate. The phosphatase showed only a single protein band when examined by polyacrylamide gel electrophoresis and a single protein peak containing all of the enzymatic activity was observed during chromatography on Sephadex G-100 column. The molecular weight of the purified enzyme was determined to be 70000 +/- 5000 by exclusion chromatography on a calibrated Sephadex G-100 column. Similar values were obtained by sucrose density centrifugation, 70000 +/- 5000, and polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, 70000 +/- 3000. The purified enzyme catalyzed the dephosphorylation of the phosphorylated forms of glycogen synthase, phosphorylase, histone, phosphofructokinase, Type II regulatory subunit of cyclic AMP-dependent protein kinase, casein and protamine. The apparent Km values for these substrates were 3.6 microM, 2.8 microM, 66 microM, 3.3 microM, 8.0 microM, 6.6 microM and 100 microM, respectively. The enzyme did not hydrolyze low molecular weight phosphate esters such as glucose 6-phosphate, glycerol phosphate, adenosine nucleotides and inorganic pyrophosphate. The activity of the enzyme towards a phosphorylated protein substrate was competitively inhibited by the addition of other substrates. These results suggest that swine kidney contains a phosphoprotein phosphatase with a rather broad substrate specificity for a number of endogenous and exogenous phosphoprotein substrates.

Acid Phosphatase↗
PubMed1990

Inhibition of plant calcium-dependent protein kinases by basic polypeptides.

Wheat embryo Ca2+-dependent protein kinase (CDPK) is inhibited by a variety of polypeptides including actin, gramicidin S, melittin, protamine, various histone preparations, histone H4 and by basic amino-acid homopolymers. Melittin (Ki 9 microM) is a non-competitive inhibitor of wheat germ CDPK and also inhibits wheat leaf CDPK and silver beet leaf CDPKs. Protamine inhibits wheat germ CDPK in an apparently competitive fashion (Ki 0.2 microM) and is also a potent, albeit less effective, inhibitor of the leaf CDPKs. Various basic amino-acid homopolymers are also potent, apparently competitive inhibitors of wheat embryo CDPK, namely poly(L-lysine) (IC50 2 nM), poly(L-ornithine) (IC50 3 nM) and poly(L-arginine) (IC50 17 nM) and also inhibit the leaf CDPKs, albeit at higher concentrations. Histone H4 and various calf thymus histone preparations inhibit wheat embryo CDPK in a fashion that is not competitive and calmodulin can substantially reverse such inhibition.

Hydrogen-Ion Concentration↗
PubMed1989

Chromatin-bound histone 1 kinase activity in synchronized HeLa S3 cells.

The chromatin-bound H1 kinase activity of HeLa S3 cells that had been synchronized with 2.7 mM thymidine for 24 h has been followed during their progression into mitosis. They were arrested at this stage of the cell cycle by adding 0.13 microM nocodazole 8 h after the removal of thymidine. The kinase was partially purified by extracting chromatin proteins with 0.4 M NaCl and fractionation with ammonium sulfate (17.5-35%), a procedure in which a significant amount of in vivo histone 1 phosphorylating activity was retained. H1 kinase activity increased as the cells entered mitosis, rising to a maximum level sevenfold higher than interphase as the mitotic index reached about 50%. A rapid decrease in activity followed this maximum approximately 2 h after cells started to accumulate in mitosis. At this time, the mitotic index was still increasing, although at a lower rate than during the increase of the kinase activity. Other protein kinase activities measured by using core histones, casein, and protamine as substrates remained fairly constant at a comparatively low level. HeLa H1 kinase activity was further distinguished from several known protein kinase activities by the lack of stimulation or inhibition with known modulators of protein phosphorylating activities.

Calcium↗
PubMed1989

Studies on the mechanism of action of a bilayer stabilizing inhibitor of protein kinase C: cholesterylphosphoryldimethylethanolamine.

Cholesterylphosphoryldimethylethanolamine is a zwitterionic compound which is a good bilayer stabilizer. As has been found with many other compounds having these properties, cholesterylphosphoryldimethylethanolamine is found to be a potent inhibitor of protein kinase C in both vesicle and micelle assay systems. The kinetics of the inhibition in Triton X-100 micelles was non-competitive with respect to ATP, histone, diolein, phorbol ester and Ca2+. It has a Ki of about 30 microns. The inhibition kinetics as a function of phosphatidylserine concentration is more complex but suggestive of competitive inhibition. Cholesterylphosphoryldimethylethanolamine does not prevent the partitioning of protein kinase C into the membrane. This inhibitor lowers the Ca2+-phosphatidylserine-independent phosphorylation of protamine sulfate by protein kinase C and directly affects the catalytic segment of the enzyme generated by tryptic hydrolysis. Thus, this zwitterionic bilayer stabilizing inhibitor of protein kinase C both competes with the binding of phosphatidylserine as well as affects the active site of protein kinase C.

Animals↗
PubMed1991

[The inhibitory effect of a third generation retinoid, R8605, on protein kinase C activity in vitro].

R8605 is a newly synthesized compound of the third generation retinoids produced by the Institute of Materia Medica. It exhibited in vitro inhibitory effects on the diolein and TPA (12-O-tetradecanoylphorbol-13-acetate) induced activation of Protein Kinase C (PKC) from rat brain and also showed inhibitory effects on the calcium/phospholipid-independent phosphorylation of protamine by PKC. The IC50 values were 65, 70, 100/mumol/L respectively. It is suggested that the inhibition of PKC activity by R8605 is related to the inhibition of tumor promotion.

Animals↗
PubMed1989

Expression of the kinase domain of mouse protein kinase C in E. coli.

The kinase domain of mouse protein kinase C type alpha has been expressed at high levels in E. coli. The protein has been purified 500-fold taking advantage of the fact that highly expressed fusion proteins precipitate out in the bacterial cell and can be solubilized in 7 M urea. The purified protein can be detected with an antibody generated against a PKC alpha derived synthetic peptide. The purified kinase domain exhibits no measurable kinase activity in a protamin phosphorylation assay. This could be an indication that post-translational modifications of the protein kinase domain which do not happen in bacteria are a requirement for functional enzyme activity or that the regulatory domain of protein kinase C is indispensable for kinase function.

Animals↗
PubMed1984

S-100 modulates Ca2+-independent phosphorylation of an endogenous protein (Mr = 19K) in brain.

A new brain enzyme (tentatively named protein kinase X), which catalyzes protamine phosphorylation modulated by S-100, was reported recently. An endogenous substrate protein (Mr = 19K) for protein kinase X was isolated from brain by means of S-100-Sepharose 4B affinity chromatography. S-100, but not calmodulin, promoted phosphorylation of the 19K Mr protein in a Ca2+-independent manner, and this reaction was inhibited by gossypol. The substrate protein, localized in the particulate fraction, was present at a much higher level in brain from adult than neonatal rats (2-day-old), a developmental change similar to that seen for protein kinase X. It is suggested that a protein phosphorylation system modulated by S-100 exists in brain, and that this process may be involved in regulation of certain neural functions.

Animals↗
PubMed1974

Protein kinase associated with Sendai virions.

A protein kinase activity has been found associated with purified Sendai virions. Most of the virion proteins and exogenous protamine served as substrates for this enzyme.

Adenosine Triphosphate↗
PubMed1987

Ca2+ phospholipid-dependent and independent phosphorylation of synthetic peptide substrates by protein kinase C.

Several synthetic peptides reproducing fragments of protamines have been used as model substrates for Ca2+/phospholipid-dependent protein kinase C, tested both in the absence of any effector (basal conditions) and upon activation by either Ca2+ and phosphatidylserine (or diacylglycerol) or limited proteolysis. Only the peptide Arg4-Tyr-Gly-Ser-Arg6-Tyr [Ga(52-65)] shares the unique property of protamines of being readily phosphorylated even under basal conditions. Optimal activity in the absence of effectors is observed with Tris/HCl buffer pH 7.5; Pipes and Hepes are less effective at pH 7.5, and at pH 6.5 basal phosphorylation is reduced. Under the best conditions for basal phosphorylation of Ga(52-65), its derivative with ornithine replaced for arginine and those corresponding to its C-terminal fragments Gly-Ser-Arg6-Tyr [Ga(57-65)] and Gly-Ser-Arg3 [Ga(57-61)], as well as the peptides Pro-Arg5-Ser2-Arg-Pro-Val-Arg [Th(1-12)], Arg4-Tyr-Arg2-Ser-Thr-Val-Ala [Th(13-23)] and Arg2-Leu-Ser2-Leu-Arg-Ala are not significantly affected though all of them, like histones, are more or less readily phosphorylated upon activation of protein kinase C by Ca2+/phosphatidylserine. The peptide Ser2-Arg-Pro-Val-Arg [Th(7-12)] however, corresponding to the C-terminal part of Th(1-12), is not phosphorylated even in the presence of activators. Limited proteolysis can roughly mimic the Ca2+/phosphatidylserine effect inducing however different extents of activation depending on the nature of the peptide substrates. Our results support the following two conclusions. Basal phosphorylation by protein kinase C in the absence of any effector requires peptide substrates whose target residue(s) are included between two extended arginyl blocks and is also dependent on pH and nature of the buffer. Peptides having extended clusters of either arginyl or ornithyl residues on the C-terminal side of serine are also readily phosphorylated, but they need activation of protein kinase by either Ca2+/phosphatidylserine or limited proteolysis. The same is true of peptides having basic residues only on the N-terminal side, or even on both sides but in limited number.

Amino Acid Sequence↗
PubMed1976

Protein kinases associated with peripheral nerve myelin. 1. Phosphorylation of endogenous myelin proteins and exogenous substrates.

When highly purified myelin from rat sciatic nerve was incubated with [gamma-32P]ATP, protein components of the membrane were phosphorylated indicating the presence of both the substrate (receptor protein) and an endogenous kinase in the membrane. Polyacrylamide gel electrophoresis of the phosphorylated membrane proteins followed by scintillation counting of gel slices and autoradiography showed that the polypeptides of molecular weights 28000, 23000 and 19000 were phosphorylated, and 32P from [gamma-32P]ATP having been incorporated into serine residues of the substrate proteins. Phosphorylation of purified myelin was Mg2+-dependent, was optimal at pH 6.5 and was not stimulated by adenosine 3',5'-monophosphate. We found that proteins other than those in myelin, such as phosvitin, casein, protamine and histones, can also act as a substrate for the membrane associated kinase. Muscle protein kinase inhibitor had no effect on the endogenous phosphorylation of myelin proteins or on the phosphorylation of phosvitin by peripheral nerve myelin protein kinase. However, the phosphorylation of histone by peripheral nerve myelin protein kinase was inhibited by the protein kinase inhibitor. After washing the membrane with 150 mM KCl the protein kinase that utilizes histone as substrate was found in the supernatant. In contrast, the endogenous phosphorylation of membrane proteins or the phosphorylation of phosvitin by the membrane associated kinase was not affected by washing. From these findings we conclude that at least two protein kinase systems exist in purified peripheral nerve myelin. One system is not inhibited by muscle kinase inhibitor, is tightly bound to the membrane and utilizes as its receptor proteins either exogenous phosvitin or endogenous membrane proteins. The second system is inhibited by muscle kinase inhibitor, is removable from the membrane and utilizes histones as its receptor proteins.

Adenosine Triphosphate↗
PubMed1992

The UL13 virion protein of herpes simplex virus type 1 is phosphorylated by a novel virus-induced protein kinase.

Herpes simplex virus type 1 (HSV-1) induces a protein kinase (PK) activity in infected cell nuclei. In vitro, the enzyme is able to phosphorylate exogenous casein (albeit inefficiently) but not protamine, can use ATP or GTP as a phosphate donor, is stimulated by high salt concentrations and is insensitive to inhibition by heparin. On the basis of these properties, the PK appears to be distinct from previously described cellular enzymes and from the cytoplasmic PK encoded by the viral US3 gene. A major substrate of the enzyme in vitro is a virus-induced protein with an Mr of 57000 (Vmw57). The gene encoding Vmw57 was mapped using recombinants between HSV-1 and HSV-2 to a region of the virus genome containing genes UL9 to UL15. Use of a monospecific rabbit antiserum showed that Vmw57 is a virion structural protein encoded by gene UL13. These results, in conjunction with previous reports that the UL13 protein contains PK sequence motifs, support the notions that the nuclear PK and Vmw57 are identical, and that the observed reactivity is due to autophosphorylation.

Animals↗
PubMed1983

Extraction of two different protein kinase activities from bovine rod outer segments.

An optimization of the rod outer segment (ROS) preparation technique is described. The protein responsible for ATP-gamma 32P binding to bovine ROS was separated from the protein active with protamine on a DEAE Sephadex column. Molecular weight evaluation on a G 100 Sephadex column gave a value of 75,000 for the protein active with ROS, and 42,000 for that active with protamine. 1.25 mM c-AMP or c-GMP reduced the activity to 0.7 or 0.8 of the control respectively. 10 mM c-GMP doubled the yield of the active protein extracted from ROS.

Adenosine Triphosphate↗
PubMed1982

Nuclear sap protein kinases from calf thymus. Substrate inhibition with histones.

1. Protamines were preferentially phosphorylated by the six protein kinase fractions isolated from calf thymus nuclear sap, but histones with the exception of H4 also proved to be acceptable substrates. 2. BSA was not a substrate for the first five kinase fractions, but was the best substrate for the seventh fraction, which also exhibited considerable activity with H4 as substrate. 3. An analysis of in vitro phosphorylation experiments with nuclear sap protein kinases reveals a decreased H2b phosphorylation in H1-depleted chromatin relative to "native" chromatin. 4. With fraction V the initial velocity patterns at fixed ATP levels and varying concentrations of histones exhibit cooperativity at lower concentrations and inhibition at higher concentrations, indicating that nuclear sap kinases might play important roles in sensitive regulatory mechanisms of histone phosphorylation in vivo.

Animals↗