Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Enzymes which traditionally have played no role in cell-directed cytotoxicity are finding their way into schemes for prodrug activation and immunotoxins owing to such useful enzymatic activity. Alkaline phosphatase, carboxypeptidases, beta-glucosidases and beta-lactamases among many others are being utilised to regenerate potent anti-cancer drugs or toxic small molecules from precursors in a bid to enhance their activity in tumours. These prodrug activation systems require the pretargeting of the enzyme to the surface of a tumour cell, usually by an antibody or its immunoreactive fragment. A recent novel approach proposes the intracellular delivery of appropriate enzymes, such as phosphodiesterases, to particular cellular compartments. There, enzyme activity can cause substantive damage resulting in cell death. Cell targeting of mammalian phosphodiesterase promises to improve upon conventional immunotoxins because of their increased cytotoxicity when targeted to the appropriate compartment and their expected lack of, or lower, immunogenicity in clinical use.
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PMID:Targeting enzymes for cancer therapy: old enzymes in new roles. 794 82

Alkaline phosphatase (APase) was isolated from the culture liquid of the streptomycin-resistant strain of Bacillus intermedius S3-19 and purified as a homogeneous preparation by ion-exchange chromatography and FPLC. Electrophoresis and gel-filtration revealed that the active enzyme is a monomer with molecular weight of 46-47 kD. The enzyme possessed phosphomonoesterase and phosphodiesterase activities with maximal levels at pH 9.5 and 55 degreesC and was stable until 60 degreesC at pH 8.0-10.0. The isolated APase exhibits a broad specificity towards a wide variety of substrates. The effect of divalent metal ions and other reagents on its catalytic activities was studied. It was concluded that alkaline phosphatase of B. intermedius is similar to the secreted alkaline phosphatases from other Bacillus species in its physicochemical and catalytic properties.
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PMID:Isolation and properties of extracellular alkaline phosphatase from Bacillus intermedius. 986 52

> Abstract The aim of this microcosm study was to determine influence of the antibiotic 2,4-diacetylphloroglucinol (DAPG) on the effect of wild-type and functionally modified Pseudomonas fluorescens F113 strains in a sandy loam soil of pH 5.4 planted with pea (Pisum sativum var Montana). The functional modification of strain F113 was a repressed production of DAPG, useful in plant disease control, creating the DAPG negative strain F113 G22; both were marked with a lacZY gene cassette. Lowering the soil pH to 4.4 significantly reduced the plant shoot and root weights and the root length, whereas the bacterial inocula had no significant effect. Both inocula significantly reduced the shoot/root ratio at pH 5.4, but this effect was not evident at the lowered or elevated (6.4) pH levels. The decrease in pH significantly increased the fungal and yeast colony-forming units from the rhizosphere (root extract), but did not affect the total bacterial c.f.u.'s. Inoculatioin with strain F113 in the pH 4.4 soil resulted in a significantly greater total bacterial population. The fungal and yeast c.f.u.'s were not significantly affected by the inocula at any pH studied. Increasing the pH significantly increased the indigenous Pseudomonas population in comparison to the reduced pH treatment and significantly increased both the introduced and total Pseudomonas populations. The antibiotic producing strain significantly reduced the total bacterial population and the NAGase activity (related to fungal activity) at pH 6.4 where the inocula population was the greatest. Alkaline phosphatase, phosphodiesterase, aryl sulfatase, beta-glucosidase, alkaline beta-galactosidase, and NAGase activities significantly increased with increasing in pH. The F113 inocula reduced the acid phosphatase activity at pH 5.4 and increased the acid beta-galactosidase activity over all the pH treatments. The results presented illustrate the variation in impact with soil pH, with implications for variability in efficacy of Pseudomonas fluorescens biocontrol agents with soil pH.http://link.springer-ny.com/link/service/journals/00248/bibs/37n4p248.html
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PMID:Effects of Pseudomonas fluorescens F113 on Ecological Functions in the Pea Rhizosphere Are Dependent on pH. 1034 Oct 54

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor (TGF)-beta superfamily, and some display potent osteogenic activity both in vivo and in vitro. The BMP signaling cascade involving BMP receptors at the cell membrane and intracellular messengers (Smads) has been elucidated, but the regulatory mechanisms of BMP signaling have not been clarified. We previously found that pentoxifyline (PeTx), a nonspecific inhibitor of phosphodiesterase (PDE), and rolipram, a PDE-4-specific inhibitor, enhance BMP-4-induced osteogenic differentiation of mesenchymal cells, probably through the elevation of intracellular cyclic adenosine monophosphate (cAMP) accumulation and modulation of BMP signaling pathways as enhanced BMP-4 action was reproduced by addition of dibutylyl-cAMP (dbcAMP). However, the precise mechanisms underlying the enhancing effects of those agents on BMP signaling were not completely revealed. As already reported, BMPs utilize a specific intracellular signaling cascade to target genes via R-Smads (Smad1,5,8), Co-Smad (Smad4) and I-Smads (Smad6,7). One possibility for cAMP-mediated effects on BMP signaling might be suppression of I-Smads expression since these proteins form a negative feedback loop in BMP signaling. To examine this possibility, changes in I-Smad (Smad6) expression on addition of dbcAMP or PeTx were examined in a bone-marrow-derived osteogenic cell line (ST2). Alkaline phosphatase activity in ST2 cells was consistently induced by BMP-4 treatment (300 ng/ml), and Smad6 mRNA expression was also induced by BMP-4 treatment. Although concurrent treatment of ST2 cells with BMP-4 and dbcAMP elicited further activation of alkaline phosphatase, addition of dbcAMP reduced BMP-4-induced Smad6 expression in a dose-dependent manner. Furthermore, detection of phosphorylated Smad1/5/8 on Western blotting analysis was prolonged, suggesting prolonged kinase activity of BMP receptors through suppressed expression of Smad6. Elevated intracellular cAMP might thus enhance BMP signaling by suppressing Smad6 induction and prolonging intracellular BMP signaling.
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PMID:Bone morphogenetic protein activities are enhanced by 3',5'-cyclic adenosine monophosphate through suppression of Smad6 expression in osteoprogenitor cells. 1620 97

PTH is a potent bone anabolic agent in vivo but anabolic effects on osteoblast differentiation in vitro are difficult to demonstrate. This study examined the role of cyclooxygenase (COX)-2 and prostaglandin (PG) production in the effects of PTH on osteoblast differentiation in vitro using marrow stromal cell (MSC) and calvarial osteoblast (COB) cultures from COX-2 knockout (KO) and wild type (WT) mice. Cells were treated with PTH (10 nM) or vehicle throughout culture. Alkaline phosphatase (ALP) and osteocalcin (OCN) mRNA levels were measured at days 14 and 21, respectively, and mineralization at day 21. cAMP concentrations were measured in the presence of a phosphodiesterase inhibitor. PTH did not stimulate differentiation in cultures from WT mice but significantly increased ALP and OCN mRNA expression 6- to 7-fold in KO MSC cultures and 2- to 4-fold in KO COB cultures. PTH also increased mineralization in both KO MSC and COB cultures. Effects in KO cells were mimicked in WT MSC cultures treated with NS-398, an inhibitor of COX-2 activity. PTH increased cAMP concentrations similarly in WT and KO COBs. Differential gene responses to PTH in COX-2 KO COBs relative to WT COBs included greater fold-increases in the cAMP-mediated early response genes, c-fos and Nr4a2; increased IGF-1 mRNA expression; and decreased mRNA expression of MAP kinase phosphatase-1. PTH inhibited SOST mRNA expression 91% in COX-2 KO MSC cultures compared to 67% in WT cultures. We conclude that endogenous PGs inhibit the anabolic responses to PTH in vitro, possibly by desensitizing cAMP pathways.
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PMID:Anabolic effects of PTH in cyclooxygenase-2 knockout osteoblasts in vitro. 1850 Nov 88

Chronic cholestasis and cholangitis may lead to the last phase known as biliary cirrhosis, characterized by cellular necrosis, apoptosis, tissue damage, local regeneration, inflammation and fibrosis. Such events are mediated by cytokines. Thalidomide and its analogs have shown to be effective immunomodulatory and hepatoprotective agents. The aim of this work was to evaluate the hepatoprotective properties of a thalidomide analog, the 3-phthalimido-3-(3,4-dimethoxyphenyl)-propanoic acid (PDA), on bile duct obstruction-induced cirrhosis. Vehicle or PDA (67 mg/kg) was orally administered twice a day to sham (Sham) or bile duct-ligated (BDL) male Wistar rats. The animals were sacrificed 28 days after treatments. Alkaline phosphatase (AP), gamma-glutamyl transpeptidase (GGTP) and alanine aminotransferase (ALT) enzyme activities as well as direct and total bilirubins concentration were determined in plasma. Lipid peroxidation (LP), glycogen and collagen were quantified in liver; in addition, histopathology was performed. PDA improved cholestasis, necrosis and fibrosis by significantly diminishing most of liver injury markers (P<0.05). Histopathology also showed remarkable liver damage amelioration. PDA effectiveness may be due to its water-solubility, stability, phosphodiesterase-4 inhibitory and immunomodulatory actions. Thalidomide and its analogs seem to be promising drugs for further treatment of biliary cirrhosis.
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PMID:The thalidomide analog 3-phthalimido-3-(3,4-dimethoxyphenyl)-propanoic acid improves the biliary cirrhosis in the rat. 1909 29

Endochondral ossification is a carefully orchestrated process mediated by promoters and inhibitors of mineralization. Phosphatases are implicated, but their identities and functions remain unclear. Alkaline phosphatase (TNAP) plays a crucial role promoting mineralization of the extracellular matrix by restricting the concentration of the calcification inhibitor inorganic pyrophosphate (PP(i)). Mutations in the TNAP gene cause hypophosphatasia, a heritable form of rickets and osteomalacia. Here we show that PHOSPHO1, a phosphatase with specificity for phosphoethanolamine and phosphocholine, plays a functional role in the initiation of calcification and that ablation of PHOSPHO1 and TNAP function prevents skeletal mineralization. Phospho1(-/-) mice display growth plate abnormalities, spontaneous fractures, bowed long bones, osteomalacia, and scoliosis in early life. Primary cultures of Phospho1(-/-) tibial growth plate chondrocytes and chondrocyte-derived matrix vesicles (MVs) show reduced mineralizing ability, and plasma samples from Phospho1(-/-) mice show reduced levels of TNAP and elevated plasma PP(i) concentrations. However, transgenic overexpression of TNAP does not correct the bone phenotype in Phospho1(-/-) mice despite normalization of their plasma PP(i) levels. In contrast, double ablation of PHOSPHO1 and TNAP function leads to the complete absence of skeletal mineralization and perinatal lethality. We conclude that PHOSPHO1 has a nonredundant functional role during endochondral ossification, and based on these data and a review of the current literature, we propose an inclusive model of skeletal calcification that involves intravesicular PHOSPHO1 function and P(i) influx into MVs in the initiation of mineralization and the functions of TNAP, nucleotide pyrophosphatase phosphodiesterase-1, and collagen in the extravesicular progression of mineralization.
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PMID:Loss of skeletal mineralization by the simultaneous ablation of PHOSPHO1 and alkaline phosphatase function: a unified model of the mechanisms of initiation of skeletal calcification. 2068 22


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