Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A triglyceride lipase was extracted from defatted pig adipose tissue powder with dilute ammonia and purified about 230-fold by a combination of ammonium sulfate fractionation, heparin-Sepharose 4B, DEAE-cellulose, and Sephadex G-150 column chromatographies and isoelectrofocusing electrophoresis. The enzyme was distinguishable in physical and kinetic properties from the two previously defined lipases in adipose tissue, lipoprotein lipase, and hormone-sensitive lipase. The purified enzyme was fully active in the absence of serum lipoprotein and was not stimulated by adenosine 3':5'-monophosphate-dependent protein kinase. In marked contrast to the already defined lipases, the enzyme was strongly inhibited by serum albumin. The enzyme had a molecular weigt of about 43,000, a pI of 5.2, and pH optimum of 7.0. The enzyme hydrolyzed triolein to oleic acid and glycerol, and did not exhibit esterase activity. The apparent Km for triolein was 0.05 mM. Physiological roles of this new species of lipase remained to be explored.
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PMID:Partial purification and characterization of a triglyceride lipase from pig adipose tissue. 1 Feb 95

Cadmium, in addition to producing a variety of toxic manifestations, is known to accumulate in certain "target" organs which include liver and kidney where histological and functional damage becomes apparent. The daily intraperitoneal injection of cadmium chloride for 21 or 45 days stimulated the activities of hepatic pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1, 6-diphosphatase and glucose-6-phosphatase elevated blood glucose and urea, and lowered hepatic glycogen in rats. Whereas chronic Cd treatment failed to alter adenosine-3', 5'-monophosphate phosphodiesterase (PDE) activity, cyclic AMP (cAMY and the activity of basal and fluoride-stimulated forms of hepatic adenylate cyclase (AC) were markedly increased. However, the cAMP binding to hepatic protein kinase was decreased as was the kinase activity ration. An acute dose of Cd decreased hepatic glycogen content and increased blood glucose, serum urea, and hepatic cAMP. Chronic exposure to Cd induced adrenal hypertrophy and augmented adrenal norepinephrine and epinephrine as well as the activity of adrenal tyrosine hydroxylase. This treatment decreased prostatic and testicular weights of mature rats. Although cAMP as well as AC activity of the prostate gland were reduced, cAMP binding to the prostatic protein kinase was increased as was the activity of the cAMP-dependent form of the enzyme. Testicular AC and PDE activities, however, were stimulated, although cAMP remained unaffected. Whereas the activities of the cAMP-dependent and the independent forms of testicular protein kinase were significantly depressed, the binding of cAMP to protein kinase from testes of Cd-treated rats was not affected. In most cases, the observed metabolic alterations persisted up to 28 days on cessation of Cd administration. Subacute Cd treatment suppressed pancreatic function as evidenced by lowered serum immunoreactive insulin (IRI) in presence of hyperglycemia, as well as by partial inhibition of phentolamine-stimulated increases in serum IRI. Although chronic Cd treatment failed to alter the concentration of brain stem norepinephrine and cerebrocortical acetylcholine esterase activity, serotonin levels of brain stem were depressed and the concentration of striatal dopamine and cerebrocortical acetylcholine were significantly elevated when compared with the values seen in control nonexposed animals.
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PMID:Aspects of the biochemical toxicology of cadmium. 17 84

Adipose tissue contains a high level of neutral esterase active against emulsions of cholesteryl oleate. The present studies show that this enzyme can also effectively hydrolyze the cholesterol esters in native rat plasma high density lipoproteins (HDL) and low density lipoproteins (LDL). The hydrolysis of lipoprotein cholesterol esters by a pH 5.2 isoelectric precipitate fraction from the freshly prepared 100,000 X g supernatant of chicken adipose tissue was low, but increased more than 50-fold on activation with cyclic AMP-dependent protein kinase. Rat adipose tissue homogenates were also very active against lipoprotein cholesterol esters, hydrolyzing as much as 60% of the total labeled cholesterol ester in HDL or LDL in 1 h. Activity was optimal at pH 7 and very low at pH 4. No protease activity was detected at pH 7 and, since assays were done in 2 mM EDTA, phospholipase A activity was presumably negligible. The results show that hormone-sensitive cholesterol esterase of adipose tissue has ready access to the neutral lipid core of plasma lipoproteins, either because the enzyme penetrates the polar shell or because the cholesterol ester in the core is exposed, at least intermittently, to allow enzyme-substrate complex formation. Whether or not this enzyme activity plays a role in lipoprotein degradation by adipose tissue remains to be determined.
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PMID:The hydrolysis of cholesterol esters in plasma lipoproteins by hormone-sensitive cholesterol esterase from adipose tissue. 21 71

Pretreatment of rats with tranexamic acid inhibited the rapid lowering of the plasma levels of acetone/kaolin-activated prekallikrein proactivator and prekallikrein caused by intravenous injection of dextran, but did not inhibit the reduction in the level of plasminogen, and potentiated the lowering of high molecular weight kininogen. By acetone/kaolin activation of normal rat plasma a mixture of surface-bound factor XIIa and unbound XIIf was obtained, and a BAEe-esterase (MW about 47,000) possessing weak kininogenase activity was present in addition to kallikrein. In activated plasma from dextran-treated rats the cleavage of XIIa was strongly reduced, and the second esterase was almost absent. It is suggested that dextran induces the loss of a plasma factor which is important for the cleavage of factor XIIa in the adopted procedure. This factor was not high molecular weight kininogen, and the lowering of plasminogen was too small to account for the reduction in PKA-activity.
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PMID:Dextran-induced lowering of parameters of the kallikrein-kinin system in rat plasma. 51 28

The effects of combinations of interferons (IFNs) and cAMP-inducing agents on the induction of differentiation of human monocytic leukemia U-937 cells were examined. IFN-gamma induced nitro blue tetrazolium (NBT) reducing activity of U-937 cells in a dose-dependent manner, while cAMP-inducing agents such as cholera toxin, prostaglandin E1, forskolin, and isoproterenol only marginally induced NBT reducing activity. However, they all synergistically increased IFN-gamma induction of NBT reducing activity. Cholera toxin was the most potent of the cAMP-inducing agents. Combination effects of IFN-gamma and cholera toxin on other differentiation-associated markers of alpha-naphthyl acetate esterase activity, morphological maturation, Fc receptors, and surface phenotype were also observed. IFN-alpha and -beta, either alone or in combination with cAMP-inducing agents, did not induce NBT reducing activity. IFN-gamma and cholera toxin also synergistically induced differentiation-associated markers in another human monocytic leukemia cell line, THP-1, and a human myeloblastic leukemia cell line, ML-1. These results suggest that cAMP/A-kinase may be an important but insufficient signal for the maturation process of myelogenous leukemia cells.
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PMID:Enhancement of interferon-gamma-induced differentiation of human monoblastic leukemia U-937 cells by cAMP-inducing agents. 170 96

Phorbol esters induce the human HL-60 promyelocytic cell line to differentiate along a monocytic pathway. This induction of differentiation may involve phorbol ester-induced activation of the phospholipid- and calcium-dependent protein kinase C. Bryostatin 1, a macrocyclic lactone, has been shown to compete with phorbol esters for binding to protein kinase C. We have confirmed that bryostatin 1 translocates activity of protein kinase C from the cytosolic to membrane fractions of HL-60 cells. The present results also demonstrate that bryostatin 1 (10 nmol/L) induces monocytic differentiation of HL-60 cells as determined by adherence, growth inhibition, appearance of monocyte cell surface antigens, and alpha-naphthyl acetate esterase staining. Furthermore, bryostatin 1 (10 nmol/L) downregulated c-myc expression and induced c-fos, c-fms, and tumor necrosis factor transcripts. These changes in gene expression induced by bryostatin 1 are similar to those associated with phorbol ester-induced monocytic differentiation of HL-60 cells. In contrast, exposure to a higher concentration of bryostatin 1 (100 nmol/L) had less of an effect on growth inhibition of HL-60 cells and changes in gene expression. Moreover, 100 nmol/L bryostatin 1 antagonized the cytostatic effects and adherence induced by phorbol esters. Our results thus suggest that bryostatin 1 activates HL-60 cell protein kinase C and that this effect is associated with induction of monocytic differentiation.
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PMID:Bryostatin 1 activates protein kinase C and induces monocytic differentiation of HL-60 cells. 245 68

The effect of staurosporine, a novel calcium/phospholipid-dependent protein kinase (protein kinase C) inhibitor, on differentiation of human promyelocytic leukemic HL-60 cells, was investigated. Staurosporine inhibited HL-60-cell proliferation in a concentration-dependent manner, but did not induce HL-60-cell differentiation by itself. When staurosporine was added to HL-60 cells treated with a suboptimal concentration (1 nM) of 1 alpha,25 dihydroxyvitamin D3 (1,25(OH)2D3), cell differentiation was enhanced in a concentration-dependent manner and the percentages of nitro blue tetrazolium reducing ability and nonspecific esterase activity-positive cells increased from 6% to 51% and from 8% to 54%, respectively, on day 4 at a concentration of 5 nM. Staurosporine (5 nM) achieved almost the same enhancement effect in cultures treated with suboptimal concentrations of 1 nM all-trans-beta-retinoic acid (RA), 3 ng/ml actinomycin D (Act D), 100 microM dibutyryl cyclic adenosine 3':5'-monophosphate (dbc AMP), and 50 microM prostaglandin E1 (PG E1). These results suggest that the inhibition of protein kinase C activity by staurosporine exerts an important role in HL-60-cell differentiation induced by various compounds. Moreover, staurosporine (5 nM) completely inhibited optimal concentrations (50 nM) of [12-o-tetradecanoyl phorbol-13-acetate (TPA)]-induced cell differentiation, but enhanced optimal concentrations of dbc AMP (1 mM)-induced cell differentiation. On the other hand, 1-(5-isoquinolinyl-sulfonyl)-2-methylpiperazine, which has been reported to inhibit cyclic adenosine 3':5'-monophosphate-dependent protein kinase (protein kinase A) as much as protein kinase C, completely inhibited both cell differentiations induced by optimal concentrations of TPA (50 nM) and induced by optimal concentrations of dbc AMP (1 mM), and did not significantly enhance HL-60-cell differentiation induced by suboptimal concentrations of 1,25(OH)2D3, RA, and dbc AMP. Therefore, these results suggest that the inhibition of protein kinase C, which is not accompanied by that of protein kinase A, is concerned with the induction of HL-60-cell differentiation.
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PMID:Staurosporine, a novel protein kinase inhibitor, enhances HL-60-cell differentiation induced by various compounds. 282

Long-chain fatty acid esters of 17 beta-estradiol and other steroid hormones, which are formed in hormone-sensitive tissues, can be regenerated to the free hormone by the action of an esterase present in the cytosol. This esterase has now been examined in bovine placenta cotyledons. Activity towards steroid fatty acid esters was accompanied by activity towards a diacylglycerol analogue and cholesteryl oleate. During purification procedures, the ratio of activities towards the diacylglycerol analogue and estradiol 17 beta-oleate remained approximately constant. Activity towards these two substrates was inhibited by increasing concentrations of HgCl2 and phenylmethanesulfonyl fluoride in a parallel manner. Upon treatment with [3H]diisopropyl fluorophosphate, a major labelled species of Mr approx. 84,000 was formed. Activation by ATP and the catalytic subunit of cAMP-dependent protein kinase occurred. These properties were very similar to those of the hormone-sensitive lipase of bovine adipose tissue previously reported and run in parallel in this study. A highly purified preparation of this latter enzyme was found to hydrolyse steroid fatty acid esters and relative activities towards such substrates, diacylglycerol analogue and cholesteryl oleate, were similar to the placenta esterase. When the two esterases were phosphorylated with [gamma-32P]ATP, a labelled species of Mr 84,000 was isolated in both cases by use of an antibody raised against purified hormone-sensitive lipase of bovine adipose tissue. It is concluded that hormone-sensitive lipase is very likely the enzyme responsible for hydrolysis of steroid fatty acid esters in bovine placenta and possibly steroid hormone target tissues in general.
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PMID:Hormone-sensitive lipase is involved in the hydrolysis of lipoidal derivatives of estrogens and other steroid hormones. 319 30

HL-60 promyelocytic leukemia cells were induced to differentiate by 1,25-dihydroxyvitamin D3 (calcitriol) into mature monocytes. Differentiation was assessed by nitro blue tetrazolium dye reduction, nonspecific esterase activity, and DNA synthesis. Terminal differentiation of cultures induced by calcitriol (10 nM) was inhibited by 80% when cells were treated simultaneously with protein kinase inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7) (32 microM) and N-[2-guanidinoethyl]-5-isoquinolinesulfonamide hydrochloride (HA1004) (320 microM). The IC50 for inhibition of calcitriol-induced differentiation was approximately 15 microM for H-7 and 170 microM for HA1004. The IC50 values for H-7 and HA1004 antagonism of calcitriol-induced differentiation are quantitatively and relatively correlated to their known action to inhibit protein kinase C activity. Treatment of cells with concentrations of 0-32 microM H-7 or 0-320 microM HA1004 alone did not affect cell growth, differentiation, or trypan blue exclusion. However, higher concentrations of H7 (greater than 32 microM) and HA1004 (greater than 320 microM) were found to be cytotoxic. The data presented suggest that calcitriol-induced differentiation is antagonized by inhibitors of protein kinase and are consistent with the hypothesis that kinase C activity is required for HL-60 cell differentiation.
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PMID:Effects of protein kinase inhibitors 1(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7) and N-[2-guanidinoethyl]-5-isoquinolinesulfonamide hydrochloride (HA1004) on calcitriol-induced differentiation of HL-60 cells. 342 61

A transplantable macrophage-like cell line has been obtained and established in W rats. This cell line is in its 85th passage and is perhaps the only established macrophage-like cell line that grows rapidly intraperitoneally in rats. The cells possess some of the typical characteristics of macrophages, such as adherence to glass, phagocytosis, presence of Fc receptors and C3d receptors, la determinants, leukocyte common antigen, lysozyme, non-specific esterase, and glycogen. The tumor also grows as solid when injected sc, intradermally, or intramuscularly. The cells have collagenase, tyrosine-specific protein kinase, and several other hydrolases. Histopathologic and ultrastructural observations suggest it to be a histiocytic tumor. The availability of a macrophage cell line of rat origin provides a useful experimental model to study different macrophage functions at the cellular and molecular level.
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PMID:Development and characterization of a rat histiocyte-macrophage tumor line. 345 75


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