Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When keratome-sliced pig epidermis was floated on Hank's balanced salt solution, we observed a rapid decrease in the intracellular level of cyclic GMP. A portion of the lost cyclic GMP was detected in the incubation medium. When the epidermis was kept in air at room temperature, the cyclic GMP level also decreased rapidly but to a lesser degree. Incubating the epidermal slice at 37 degrees C in Hank's balanced salt solution with the addition of 3-isobutyl-1-methyl xanthine (IBMX) prevented the decrease. Also, after the cyclic GMP level had fallen, it could be raised to be the in vitro level by the addition of IBMX. Increased amounts of cyclic GMP were detectable in the medium in this case. These data indicate that the decrease in cyclic GMP in ischemic epidermis is due to sudden activation of epidermal cyclic GMP-phosphodiesterase and also in part due to leakage of cyclic GMP extracellularly. In contrast to the rapid decline in the cyclic GMP level, ischemia caused a rapid and transient increase in epidermal cyclic AMP. This confirms previous data by ourselves and by others (Br J Dermatol 92: 249-254, 1975; J Invest Dermatol 68:125-127, 1977). These "ischemic effects" must be avoided in order to measure the "in vivo level" of cyclic nucleotides in epidermis.
J Invest Dermatol 1979 Sep
PMID:Cyclic GMP System in epidermis: I. Effect of ischemia. 8 73

It has been demonstrated previously that nontransformed C3H/10T1/2CL8 mouse embryo fibroblasts (10T1/2) can induce a state of reversible growth inhibition in cocultured malignantly transformed mouse fibroblasts and that this inhibition is modulated by serum concentration. The present study suggests that cyclic nucleotides may be implicated in this intercellular communication. The phosphodiesterase inhibitors theophylline, caffeine, and 3-isobutyl-1-methylxanthine (IBX) at concentrations of 10(-3) M, maintained continuously, were all found to inhibit the expression of 3-methylcholanthrene-induced malignant transformation when added 7 days after removal of carcinogen. IBX was the most potent, causing 100% inhibition at 10(-4) M and 70% inhibition at 10(-5) M. This inhibition was partially reversible in the former case and completely reversible in the latter case by removal of drug. Complete inhibition by 10(-4) M IBX was still observed when treatment was delayed 21 days postcarcinogen. In reconstruction experiments, utilizing confluent monolayers of 10T1/2 cells overlaid with transformed cells, IBX caused a dose-dependent inhibition of colony size of the transformed cells. Adenosine cyclic 2':3'-monophosphoric acid (cAMP) and N6,O2'-dibutyryladenosine cyclic 3':5'-monophophoric acid potentiated this response. The presence of non-transformed 10T1/2 cells was required for this effect, since a concentration of IBX (10(-4) M) inhibitory for the growth of transformed cells in mixed cultures was without effect on the growth rate, plating efficiency, or saturation density of pure cultures of 10T1/2 cells or of their transformed counterparts. Conditioned medium removed from IBX-treated 10T1/2 cells was not growth inhibitory for transformed cells, indicating a requirement for cell-cell contact. IBX caused a dose-dependent increase in intracellular cAMP in confluent 10T1/2 cells and a more pronounced increase in cAMP concentration in the culture medium of these cells. The dose-response effects of IBX on growth inhibition of malignant cells in mixed cultures appear to correlate well with its ability to elevate cAMP levels. Thus, IBX increased the capacity of 10T1/2 cells to cause reversible growth arrest of transformed cells and appears to act in a manner analogous to the previously reported effects of serum.
Cancer Res 1979 Sep
PMID:Modulation of cellular interactions between C3H/10T1/2 cells and their transformed counterparts by phosphodiesterase inhibitors. 8 99

The hypothesis that hepatitis B infection is etiologically related to hepatoma has been investigated by studying the interrelationships between hepatitis B surface antigen (HBsAg, Australia antigen) and the fast-moving 5'-nucleotide phosphodiesterase Band V isoenzyme (5'-NPDase-V). Sera from 58 patients with viral hepatitis were tested for 5'-NPDase-V and HBsAg. The isoenzyme was found in 34 of 37 patients who were also positive for HBsAg but in only 4 of 21 hepatitis patients who were HBsAg negative. Five patients convalescing from hepatitis were negative for both HBsAg and the isoenzyme. Preparative gel electrophoresis showed that these 2 markers were different proteins. Of 34 hepatoma patients, 29 were positive for 5'-NPDase-V. Only 1 isoenzyme-positive patient was positive for HBsAg by counterimmunoelectrophoresis. However, of 16 isoenzyme-positive hepatoma patients available for radioimmunoassay, 8 were NBsAg positive (50%). None of 21 hepatoma samples tested for antibody to NBsAg was positive. Of 21 "normal" carriers of HBsAg and 10 carriers with Down's syndrome, 4 persons were detected with the isoenzyme. The results suggest that HBsAg and 5'-NPDase-V in the presence of liver damage are associated and thus provide a new marker enzyme between hepatitis B infection and hepatoma.
Cancer Res 1975 Sep
PMID:5'-nucleotide phosphodiesterase isoenzyme in patients with hepatitis B infection. 16 56

The role of cyclic adenosine 3':5'-monophosphate (cyclic 3':5'-AMP) in the regulation of cell division in lymphocytes obtained from healthy donors and from patients with chronic lymphocytic leukemia (CLL) was investigated by determining the levels of cyclic 3':5'-AMP and glycogen and also the activities of several enzymes that are closely associated with the metabolism of these cellular components. Intracellular levels of cyclic 3':5'-AMP were measured in normal and CLL lymphocytes in nondividing, dividing, and quiescent [after phytohemagglutinin (PHA) addition]states. In normal lymphocytes the levels of cyclic 3':5'-AMP fluctuated throughout the cell cycle after PHA addition, whereas in CLL lymphocytes the levels were approximately 3-fold lower than in normal cells and remained relatively constant before, during, and after mitogenic stimulation. Normal cells contained approximately 3-fold lower levels of glycogen than CLL cells, whereas glycogen phosphorylase activities were increased 2- to 4-fold above those in nondividing cells in normal but not in CLL lymphocytes after stimulation with PHA. Furthermore, cyclic 3':5'-AMP phosphodiesterase activities were higher in CLL lymphocytes than in normal ones. Collectively, these studies demonstrated that (a) the intracellular levels of cyclic 3':5'-AMP differ in these two cell types; (b) the levels of cyclic 3':5'-AMP and glycogen qualitatively correlate with the activities of the enzymes that are related to these components; and (c) an inverse relationship between the levels of cyclic 3':5'-AMP and cell growth exists in mitogen-stimulated lymphocytes from healthy donors but not from patients with CLL. These biochemical differences are presumed to exist between normal and "leukemic" lymphocytes, but alternatively they may reflect normal populations of immunologically distinct lymphocytes.
Cancer Res 1975 Sep
PMID:Cyclic adenosine 3':5'-monophosphate levels and activities of related enzymes in normal and leukemic lymphocytes. 16 62

For establishment of a reproducible model of human neuroblastoma, 2 to 5 million of established neuroblastoma cell lines (SK-N-SH, SK-N-MC) were injected s.c. or i.p. into 20 nu/nu mice of a predominantly Swiss back-ground. Following latency periods of 8 to 21 days, tumors developed at the injection site and grew to 4-ml volumes within 3 weeks. Histologically, the tumors resembled the original metastases from which the tumors were derived; however, the SK-N-SH appeared to have evidence of morphological differentiation. When compared to monolayer culture, the heterotransplanted SK-N-SH tumor had decreased dopamine-beta-hydroxylase activity and elevated cyclic adenosine 3':5'-monophosphate phosphodiesterase activity. Activity of cyclic adenosine 3':5'-monophosphate phosphodiesterase in the transplanted SK-N-MC tumor was not appreciably different from the activity in the cultured cells. Serum dopamine-beta-hydroxylase levels in the mice bearing SK-N-SH tumor increased threefold. The SK-N-MC cultured cells lacked dopamine-beta-hydroxylase and did not alter existing serum levels in the SK-N-MC tumor-bearing mice. 67Ga injected i.v. was found to localize in the tumor after 24 hr. Human neuroblastoma in the nude mouse can be a reproducible and informative model for tumor pharmacology, screening, radionuclides, tumor localization and imaging, and investigating morphological differentiation.
Cancer Res 1975 Sep
PMID:Human neuroblastoma in nude mice. 16 65

Phosphodiesterase I (EC 3.1.4.1) activity was detected in normal human blood serum. The enzyme is stable at laboratory temperature for three days, but is inactivated at pH less than 7. The pH for optimum activity increases with the substrate concentration (under the conditions used, from pH 9.0 to 10.2) and, conversely, the Km increases with pH and buffer concentration. The enzyme is inhibited by ethylenediaminetetraacetate but not by phosphate (0.1 mol/liter). We developed a simple quantitative method for its determination, based on hydrolysis of the p-nitrophenyl ester of thymidine 5'-monophosphate and subsequent measurement of the liberated p-nitrophenol at 400 nm in NaOH (0.1 mol/liter). Normal values (mean +/- 2 SD) were determined to be 33 +/- 6.4 U/liter. Preliminary studies indicate that phosphodiesterase I activity is greater than normal in serum of patients with necrotic changes in the liver or kidney or in cases of breast cancer, but not in that of patients with myocardial infarction, bone cancer, lung cancer, or chronic liver cirrhosis.
Clin Chem 1975 Sep
PMID:Determination of phosphodiesterase I activity in human blood serum. 16 91

The denatured alpha1(I) chain and the cyanogen bromide peptide, alpha1(I)-CB5, of chick skin collagen cause the release of serotonin and leakage of lactic dehydrogenase from human platelets in a manner similar to the release reaction mediated by adenosine diphosphate and native collagen. These peptides also cause a decrease in the level of adenosine 3':5'-monophosphate (cAMP) in platelets. Adenylate cyclase activity of platelets is partially inhibited by these peptides as well as by native collagen, ADP, and epinephrine, but cAMP phosphodiesterase activity is unaltered by these substances. In contrast, the level of platelet guanosine 3':5'-monophosphate (cGMP) is increased by the collagen peptides as well as the other aggregating agents. The increase is associated with increased guanylate cyclase, but normal cGMP phosphodiesterase activities of platelets. Optical rotatory and viscometric measurements of the alpha1 chains and alpha1-CB5 of chick skin in 0.01 M phosphate/0.15 M sodium chloride, pH 7.4, at various temperatures as a function of time indicate that no detectable renaturation occurs at 37 degrees for at least 30 min of observation. Molecular sieve chromatography of alpha1-CB5 in the phosphate buffer at 37 degrees shows that its elution position is identical to that performed under denaturing conditions (at 45 degrees) with no evidence of higher molecular weight aggregates, and the alpha1-CB5 glycopeptide fraction eluting from the column at the position of its monomer retains the platelet aggregating activity. Additionally, electron microscopic examination of the platelet-rich plasma that had been reacted with these peptides fail to show any ordered collagen structures. These data indicate that the denatured alpha1 chain and alpha1-CB5 glycopeptide of chick skin collagen mediate platelet aggregation through the "physiologic" release reaction in a manner similar to that induced by other aggregating agents such as ADP, epinephrine, or native collagen, and support the conclusion that the aggregating activity of the alpha1 chain and alpha1-CB5 is not likely to be due to the formation of polymerized products.
J Biol Chem 1975 Sep 10
PMID:Interaction of a chick skin collagen fragment (alpha1-CB5) with human platelets. Biochemical studies during the aggregation and release reaction. 16 61

Inhibition of the electrically induced contractions of the guinea-pig ileum has been shown to be a reliable index to the relative potency of various narcotic analgesics. This property suggests that this preparation might be used as a model in attempts to elucidate the mechanism(s) by which morphine induces analgesia in the central nervous system. Since it has been demonstrated that some adenosine derivative may function as an endogenous inhibitory transmitter in the gut, the effects of adenosine, adenosine triphosphate (ATP) and morphine on the ileum were further characterized and compared. Morphine, adenosine and ATP produce a substantial inhibition of the isometric contractions induced by transmural field stimulation. The inhibition produced by each is antagonized by 2.5 times 10(-7) M tolazoline whereas that produced by ATP is potentiated by 4 times 10(-7) M 5-hydroxytryptamine. The inhibitory effects of morphine and ATP can also be markedly potentiated by two of the several phosphodiesterase inhibitors tested, Ro 20-1724 and dipyridamole. In addition, pretreatment of the ileum with either adenosine, ATP or morphine can produce a significant potentiation of the inhibitory effects of norepinephrine. The above suggests that cyclic adenosine 3',5'-monophosphate may play a role in mediating some of the inhibitory effects produced by exogenous adenosine, ATP and morphine. In addition, the similarities between the effects produced by these substances indicates that the biochemical pathways responsible for mediating the effects of each may share some common elements.
J Pharmacol Exp Ther 1975 Sep
PMID:Interactions of morphine, adenosine, adenosine triphosphate and phosphodiesterase inhibitors on the field-stimulated guinea-pig ileum. 16 45

Cyclic adenosine 3':5'-monophosphate added to the starvation media of Dictyostelium discoideum amoebae induces both intracellular and extracellular phosphodiesterase activities of these cells. The induced enzyme activity appears several hours earlier than that in starved cells which have not been induced with cyclic nucleotide. In both cases, the appearance of enzyme is inhibited by cycloheximide, and actinomycin D, and daunomycin. The KmS for the extracellular enzyme(s) of nucleotide-induced and uninduced control cells are identical. The induction of enzyme activity seems specific for cyclic adenosine 3':5'-monophosphate since cyclic guanosine 3':5'-monophosphate, as well as other nucleotides, have no effect. No differences in the activity or excretion of either N-acetylglucosaminidase or the inhibitory of the extracellular phosphodiesterase are observed between cyclic adenosine 3':5'-monophosphate-induced and control cells. A direct activation of phosphodiesterase by cyclic adenosine 3':5'-monophosphate can be excluded, since the addition of this nucleotide to cell lysates has no effect on the enzyme activity.
J Biol Chem 1975 Sep 25
PMID:Induction of phosphodiesterase by cyclic adenosine 3':5'-monophosphate in differentiating Dictyostelium discoideum amoebae. 17 Feb 56

Derivatives of adenosine 3',5'-cyclic phosphate (cAMP) with modifications in both the 2' and the 8 positions were synthesized and their enzymic activities as activators of cAMP-dependent protein kinase and as substrates for and inhibitors of cAMP phosphodiesterases were determined. Three types of derivatives were investigated: 8-substituted derivatives of O2'-Bt-cAMP, 8-substituted derivatives of 9-beta-D-arabinofuranosyladenine 3',5'-cyclic phosphate (ara-cAMP), and 8-substituted derivatives of 8,2'-anhydro-9-beta-D-arabinofuranosyladenine 3,'5'-cyclic phosphate (8,2'-anhydro-cAMP). The 8-substituted O2'-Bt-cAMP derivatives were synthesized by acylation of the preformed 8-substituted cAMP (8-HS-cAMP, 8-MeS-cAMP, and 8-PhCH2S-cAMP). 8-Br-O2'-tosyl-cAMP was sued as an intermediate for the preparation of 8,2'-anhydro-cAMP derivatives (8-HO-, 8-SH-, 8-H2N-, and 8-H3 CHN derivatives of 8,2'-anhydro-cAMP). 8-Substituted ara-cAMP derivatives were obtained by ring opening of 8-HO-8,2'-anhydro-cAMP with H+/H2O, NH3/MeOH, or MeONa/MeOH (to yield the 8-HO-, 8-H2N-, and 8-MeO-ara-cAMP derivatives). All of these doubly modified derivatives of cAMP are less than one-hundredth as active as cAMP at activating protein kinase and did not serve as substrates for the phosphodiesterase. These data show that the general inactivity of 2' derivatives of cAMP with kinase was not overcome by addition of an 8-substituent, even though many 8-substituted derivatives of cAMP activate the kinase more efficiently than does cAMP itself. In addition they show that while 2'-modification were tolerated by the phosphodiesterase, addition of an 8-substituent countermanded the allowable 2'-modification. The 8-substituted derivates of 02'-Bt-cAMP were found in general to be slightly better inhibitors of phosphodiesterase than the parent compounds containing no o2'-Bt substitution. As a group, the 8-substituted ara-cAMP derivatives were poorer inhibitors of phosphodiesterase than 8-substituted cAMP derivatives while the 8,2'-anhydro-cAMP derivatives were much poorer inhibitors than the 8-substituted ara-cAMP derivatives.
Biochemistry 1975 Sep 23
PMID:8-Substituted derivatives of adenosine 3',5'-cyclic phosphate require an unsubstituted 2'-hydroxyl group in the ribo configuration for biological activity. 17 Sep 58


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