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

---

Query: EC:3.1.4.37 (CNPase)
539 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An improved method for the assay of cyclic nucleotide phosphodiesterases (CNPases) is described in which residual 3H-cAMP or 3H-cGMP is separated from products by chromatography on thin layers of PEI-cellulose. Comparison of CNPase activity in crude or purified kidney enzyme assayed by the PEI-cellulose method with a batch anion-exchange resin method showed serious underestimation of activity by the latter method. The batch method underestimated CNPase activity by 34-82%. The error was due to substantial binding of nucleosides (adenosine and guanosine) to the resin, which is assumed not to occur by those using this method.
...
PMID:Comparison of batch and chromatographic assays of cyclic nucleiotide phosphodiesterases. 18 7

Bovine cerebrum, including the corpus callosum, and a human oligodendroglioma were investigated by an immunohistochemical technique to determine the distribution of 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNP). Also, three human oligodendrogliomas (ODG) were characterized by an immunoblot procedure to identify a protein(s) with cross-reacting determinants to CNP and assayed for CNP activity. CNP was localized to oligodendrocytes in the corpus callosum and subcortical white matter and gray matter. Also, nerve fibers appeared to be stained. Further, cells of the human oligodendroglioma were immunostained which were similar in morphology to those cells stained in the bovine cerebrum; however, fewer than 5% of the oligodendroglioma cells were immunostained. Immunoblotting revealed two separate and distinct bands for the three oligodendrogliomas, showing cross-reactivity to bovine CNP antisera at about 53,000 and 46,000 daltons. Specific CNP activity of the three human oligodendrogliomas ranged from 0.4 to 1.6 mumole of 2':3'-cAMP hydrolyzed/min/mg protein.
...
PMID:An immunochemical investigation of 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNP) in bovine cerebrum and human oligodendroglioma. 258 Sep 90

The adrenal medulla contains an enzyme which catalyzes the hydrolysis of 2',3'-cAMP to 2'-AMP. For the parameters which have been examined, the adrenal medulla 2',3'-cAMP phosphodiesterase appears to be similar to brain 2',3'-cyclic nucleotide 3'-phosphodiesterase (also commonly referred to as CNPase). The apparent Km of the adrenal medulla CNPase for 2',3'-cAMP is 0.88 mM. The enzyme activity is unaltered by either EDTA, MgCl2 or CaCl2 in the presence or absence of calmodulin. The apparent molecular weight is 102,500 daltons. The function of the enzyme in either the brain or the adrenal medulla is, at the present time, unknown.
...
PMID:Identification of 2',3'-cyclic nucleotide 3'-phosphodiesterase in bovine adrenal medulla. 370 18

We aimed to study the level of CNPase activity in the cerebrospinal fluid of patients with demyelinating diseases and other neurological diseases, particularly multiple sclerosis, with reference to CSF myelin basic protein content. CNPase activity was measured paper chromatographically using radioactive 2',3'-cAMP as a substrate. Myelin basic protein content was measured with a radioimmunoassay. The mean level of CNPase activity was significantly higher for multiple sclerosis than for nonneurological controls. Dividing the disease phases of multiple sclerosis into the three periods, the CNPase activity was found to be significantly elevated in the worsening period and reduced in the improving period and the inactive period. The level of CNPase activity in the cerebrospinal fluid of multiple sclerosis coincided with the clinical activity of the disease. The level of CNPase activity correlated well (r = 0.84) with the level of myelin basic protein content in cerebrospinal fluid. The ratio for CNPase activity and myelin basic protein content in cerebrospinal fluid was almost the same as that in human central nerve myelin. We concluded that CNPase activity in the cerebrospinal fluid from neurological patients is an indicator of destruction of myelin in the central nervous system, and the measurement of CNPase activity in the cerebrospinal fluid of multiple sclerosis could be useful in the clinical management.
...
PMID:2',3'-Cyclic nucleotide 3'-phosphodiesterase activity in the cerebrospinal fluid of patients with demyelinating diseases. 608 71

The enzyme, 2':3'-cyclic nucleotide 3'-phosphodiesterase (2':3'-cNMP-3'-ase) has been used as a marker in the nervous system for the presence of myelin membrane or myelin-producing glial cells. In this study, goldfish and bovine neural retinas are found to have high levels of such a diesterase activity. Analysis of retinal tissue incubated with 2':3'-cAMP shows only 2'-AMP as the reaction product, indicating the selective hydrolysis of the cyclic nucleotide. Microdissection of the goldfish retina demonstrates the highest 2':3'-cNMP-3'-ase activity in the region of the photoreceptors. A fraction enriched in bovine rod outer segments has about a 5-fold increase in specific enzyme activity when compared to whole retina preparations. These data suggest that 2':3'-cNMP-3'-ase is either closely associated with or is an intrinsic feature of vertebrate photoreceptor elements. The retina, which contains this enzyme, may serve as a model to investigate the influence of 2':3'-cyclic nucleotides on a function of the nervous system.
...
PMID:Identification of 2':3'-cyclic nucleotide 3'-phosphodiesterase in the vertebrate retina. 624 10

A novel method has been developed for the preparation of nearly pure separate cultures of astrocytes and oligodendrocytes. The method is based on (a) the absence of viable neurons in cultures prepared from postnatal rat cerebra, (b) the stratification of astrocytes and oligodendrocytes in culture, and (c) the selective detachment of the overlying oligodendrocytes when exposed to sheer forces generated by shaking the cultures on an orbital shaker for 15--18 h at 37 degrees C. Preparations appear greater than 98% pure and contain approximately 1-2 x 10(7) viable cells (20--40 mg of cell protein). Three methods were used to characterize these two culture t ypes. First, electron microscopic examination was used to identify the cells in each preparation (mixed and separated cultures of astrocytes and oligodendrocytes) and to assess the purity of each preparation. Second, two oligodendroglial cell markers, 2',3'-cyclic nucleotide 3'-phosphohydrolase (EC 3.1.4.37) and glycerol phosphate dehydrogenase (EC 1.1.1.8) were monitored. Third, the regulation of cyclic AMP accumulation in each culture type was examined. In addition to these studies, we examined the influence of brain extract and dibutyryl cAMP on the gross morphology and ultrastructure of each preparation. These agents induced astroglial process formation without any apparent morphological effect on oligodendrocytes. Collectively, the results indicate that essentially pure cultures of astrocytes and of oligodendrocytes can be prepared and maintained. These preparations should significantly aid in efforts to examine the biochemistry, physiology, and pharmacology of these two major classes of central nervous system cells.
...
PMID:Preparation of separate astroglial and oligodendroglial cell cultures from rat cerebral tissue. 624 68

2',3'-Cyclic nucleotide 3'-phosphodiesterase (CNP, EC 3.1.4.37) has been isolated from rat brain myelin by chromatography on successive columns of phenyl-Sepharose CL-4B, CM-Sepharose CL-6B, and 8-(6-aminohexyl) amino-2'AMP-Sepharose 4B. From 15 g of rat brain, approximately 400 micrograms of pure CNP was obtained, with a specific activity of 1,200 (2',3'-cyclic AMP) units/mg protein. The Km of the rat enzyme was 3.7 mM, using 2',3'-cAMP as the substrate. Isoelectric focusing of the enzyme indicated a broad isoelectric range of 8.5-9.0. On SDS polyacrylamide gels, rat CNP appears as two protein bands of approximately 48,000 and 50,000 M.W., with an upper band intensity of about 1/10 that of the lower band. The relative intensities of the bands for CNP and the molecular weights correspond to the Wolfgram proteins W1 and W2 described by other investigators. The amino acid analysis of the purified rat enzyme compared favorably with reported determinations for the bovine enzyme and also with reported values for the rat Wolfgram proteins W1 and W2.
...
PMID:Purification of rat 2',3'-cyclic nucleotide 3'-phosphodiesterase. 625 58

Cyclic AMP (cAMP) is known to induce the activity of the myelin enzyme 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP; EC 3.1.4.37) in C6 rat glioma cells. This report shows that CNP is also inducible in oligodendrocytes explanted from 1-day-old rat cerebrum and grown in tissue culture. Induction was observed after a 1-day treatment with 1 mM N6, O2-dibutyryl cyclic AMP (dbcAMP) and was maximal after 5 days, reaching 200-240% of control. Induction was observed both in mixed cerebral cell cultures containing oligodendrocytes and astrocytes, and in purified cultures of oligodendrocytes prepared by a differential shakeoff procedure. Addition of dbcAMP to the cultures 3-9 days after the cells were explanted from rat brain induced CNP activity, but no induction was observed when dbcAMP treatment was begun 13 or more days after explanation. These results demonstrate that one component of myelin, CNP, is inducible in oligodendrocytes by a cAMP-mediated mechanism, and suggest a role for cAMP in the regulation of the myelin-associated functions of oligodendrocytes.
...
PMID:Cyclic AMP induction of the myelin enzyme 2',3'-cyclic nucleotide 3'-phosphohydrolase in rat oligodendrocytes. 630 62

Activity of 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNP) of human erythrocyte membranes was determined in the presence of various brain CNP inhibitory compounds. Also, the hydrolysis of 2':3'-cAMP and 2':3'-cCMP by CNP of human platelets and lymphocytes was confirmed by thin layer chromatography and CNP activity was measured in lymphocytes, platelets, erythrocytes and CNS myelin. Human erythrocyte CNP activity was reduced 75 percent by the organomercurial p-chloromercuriphenyl sulfonate (1 X 10(-4) M), 46 percent by thimerosal (1 X 10(-4) M) and 35 percent by cupric chloride (1 X 10(-3) M). The 2'-AMP or 2'-CMP isomer was produced, exclusively, by the hydrolysis of 2':3'-cAMP or 2':3'-cCMP, respectively, by CNP of human lymphocytes and platelets and indicates a CNP-like activity is not only present in erythrocytes and the central and peripheral nervous systems, but also platelets and lymphocytes. CNP activities of human erythrocytes, human human and rat lymphocytes and human platelets were less than 4 percent of the activity of human and bovine CNS myelin.
...
PMID:An investigation of 2':3'-cyclic nucleotide 3'-phosphodiesterase (EC 3.1.4.37, CNP) in peripheral blood elements and CNS myelin. 632 43

2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) was phosphorylated in vivo, in brain slices and in a cell free system. Phosphoamino acid analysis of immunoprecipitated CNP labeled in vivo and in brain slices revealed phosphorylation of phosphoserine (94%) and phosphothreonine (5%) residues. Phosphorylation of CNP increased by 3-fold after brain slices were incubated with forskolin. Similarly, incubation of isolated myelin with [gamma-32]ATP with cAMP (5 microM) and cAMP (5 microM)+catalytic unit of cAMP dependent protein kinase dramatically increased CNP2 phosphorylation by 4- and 6-fold, respectively. It is feasible that CNP2 was predominantly phosphorylated on serine and/or threonine residues of the amino terminal peptide of CNP2, and this phosphorylation was catalyzed by protein kinase A. Phosphorylation of CNP1 and CNP2 increased 2-fold by incubating brain slices with phorbol ester. Forskolin and phorbol ester increased the phosphorylation of single, but distinct, CNP peptides. We present the first biochemical evidence that CNP2, on a protein mass basis, is far more heavily phosphorylated than CNP1, suggesting there are more phosphorylation sites on CNP2 than CNP1 and that at least one site is located on the 20-amino acid terminus of CNP2 and that it is likely a PKA site.
...
PMID:In vivo phosphorylation of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP): CNP in brain myelin is phosphorylated by forskolin- and phorbol ester-sensitive protein kinases. 806 30


1 2 Next >>

---