共查询到20条相似文献,搜索用时 31 毫秒
1.
J. S. Law S. A. McBride S. Graham N. R. Nelson B. M. Slotnick R. I. Henkin 《Biological trace element research》1988,16(3):221-226
The effect of zinc deficiency on calmodulin function was investigated by assessing the in vivo activity of two calmodulin
regulated enzymes, adenosine 3′,5′-monophosphate (c-AMP) and guanosine 3′,5′-monophosphate (c-GMP) phosphodiesterase (PDE)
in several rat tissues. Enzymatic activities in brain, heart, and testis of rats fed a zinc deficient diet were compared with
activities in these tissues from pair fed, zinc supplemented rats. In testis, a tissue in which zinc concentration decreased
with zinc deficient diet, enzyme activities were significantly decreased over those in rats who were pair fed zinc supplemented
diets. In brain and heart, tissues in which zinc concentrations did not change with either diet, enzymatic activities between
the groups were not different. These results indicate that zinc deficiency influences the activity of calmodulin-regulated
phosphodiesterases in vivo supporting the hypothesis that zinc plays a role in calmodulin function in vivo in zinc sensitive
tissues. 相似文献
2.
HPLC separation of ionic samples tends to be more complicated and difficult to understand than that of non-ionic compounds.
On the other hand, band spacing is much more easily manipulated for ionic than for neutral samples. Ion-suppressing RP-HPLC
method was used with organic modifier and aqueous buffer solution. In this work, five mononucleotides of cytidine-5-monophosphate
(5′-CMP) disodium salt, uridine-5-monophosphate disodium salt (5′-UMP), guanosine-5-monophosphate disodium salt (5′-GMP),
inosine-5-monophosphate disodium salt (5′-IMP), and adenosine-5-monophosphate disodium salt (5′-AMP) were examined. Acetic
acid and sodium phosphate were used as buffers, and methanol as an organic modifier. A new relationship between the retention
factor and the buffer concentration at a fixed modifier content (5% of methanol) could be expressed by fol|lowing:k=(k
−1+k
0 (K
B/K
S)C
B
a)/(1+(K
B/K
S)C
B
a), whereC
B was the concentration of buffer. Using this relationship, the calculated values closely matched the experimental data. The
derived relationship showed that as the buffer concentration increased, the retention factor approached a certain value, and
this was buffer dependent. 相似文献
3.
Horinouchi N Ogawa J Kawano T Sakai T Saito K Matsumoto S Sasaki M Mikami Y Shimizu S 《Applied microbiology and biotechnology》2006,71(5):615-621
2′-Deoxyribonucleosides are important as building blocks for the synthesis of antisense drugs, antiviral nucleosides, and 2′-deoxyribonucleotides for polymerase chain reaction. The microbial production of 2′-deoxyribonucleosides from simple materials, glucose, acetaldehyde, and a nucleobase, through the reverse reactions of 2′-deoxyribonucleoside degradation and the glycolytic pathway, was investigated. The glycolytic pathway of baker’s yeast yielded fructose 1,6-diphosphate from glucose using the energy of adenosine 5′-triphosphate generated from adenosine 5′-monophosphate through alcoholic fermentation with the yeast. Fructose 1,6-diphosphate was further transformed to 2-deoxyribose 5-phosphate in the presence of acetaldehyde by deoxyriboaldolase-expressing Escherichia coli cells via d-glyceraldehyde 3-phosphate. E. coli transformants expressing phosphopentomutase and nucleoside phosphorylase produced 2′-deoxyribonucleosides from 2-deoxyribose 5-phosphate and a nucleobase via 2-deoxyribose 1-phosphate through the reverse reactions of 2′-deoxyribonucleoside degradation. Coupling of the glycolytic pathway and deoxyriboaldolase-catalyzing reaction efficiently supplied 2-deoxyribose 5-phosphate, which is a key intermediate for 2′-deoxyribonucleoside synthesis. 2′-Deoxyinosine (9.9 mM) was produced from glucose, acetaldehyde, and adenine through three-step reactions via fructose 1,6-diphosphate and then 2-deoxyribose 5-phosphate, the molar yield as to glucose being 17.8%. 相似文献
4.
Kohji Hasunuma 《Journal of plant research》1985,98(3):203-217
A wild type strain ofNeurospora crassa produced aerial hyphae and luxuriant conidia in standing culture in low phosphate liquid media.nuc-1 andnuc-2, which have no ability to derepress repressible cyclic phosphodiesterase (cPDase) (3′; 5′-cyclic AMP 5′-nucleotidohydrolase,
EC 3.1.4.17) and several other repressible enzymes, did not form them. Heterocaryon between them restored the abilities not
only to produce aerial hyphae and conidia but also to produce cPDase. Revertants fromnuc-1 and a mutant in alkaline phosphatase,pho-2, produced aerial hyphae and conidia in low phosphate condition, whereas a mutant in cPDase,pho-3, produced only a limited amount of them.
In media containing low levels of 2′, 3′-cAMP, the wild type, the revertants fromnuc-1, pho-2 andpho-3 produced aerial hyphae and conidia in abundance, whereas in media containing 3′, 5′-cAMP these strains produced no or only
limited amounts of them. In low phosphate medianuc-1, nuc-2 andpho-3 showed higher levels of 3′, 5′-cAMP as compared with those strains which have the ability to derepress cPDase. The cPDase
activities in crude mycelial extracts fromnuc-1 andpho-3 grown in low phosphate media were 5.6 and 17.5% of that ofpho-2 when assayed for 3′,5′-cAMP at an intracellular level of 2 μM. 相似文献
5.
Broken cells ofEscherichia coli contain an enzyme system breaking down cyclic 3′,5′-adenosine monophosphate (Ado-3′,5′-P). The enzyme splitting this nucleotide
is located in the supernatant fraction at 20,000 ×g. Some characteristics of the enzyme were studied. In contrast with the animal enzyme theEscherichia coli enzyme is not inhibited by caffeine. 相似文献
6.
LV Skosareva NA Lebedeva NI Rechkunova EA Maltseva PE Pestryakov OI Lavrik 《Biochemistry. Biokhimii?a》2012,77(5):524-531
The interaction of nucleotide excision repair (NER) proteins (XPC-HR23b, RPA, and XPA) with 48-mer DNA duplexes containing the bulky lesion-mimicking fluorescein-substituted derivative of dUMP (5-{3-[6-(carboxyamidofluo-resceinyl)amidocapromoyl]allyl}-2′-deoxyuridine-5′-monophosphate) in a cluster with a lesion of another type (apurinic/apyrimidinic (AP) site) has been studied. It is shown that XPC-HR23b is modified to a greater extent by the DNA duplex containing an AP site opposite nucleotide adjacent to the fluorescein residue than by DNA containing an AP site shifted to the 3′-or 5′-end of the DNA strand. The efficiency of XPA modification by DNA duplexes containing both AP site and fluorescein residue is higher than that by DNA lacking the bulky lesion; the modification pattern in this case depends on the AP site position. In accordance with its major function, RPA interacts more efficiently with single-stranded DNA than with DNA duplexes, including those bearing bulky lesions. The observed interaction between the proteins involved in nucleotide excision repair and DNA structures containing a bulky lesion processed by NER and the AP site repaired via base excision repair may be significant for both these repair pathways in cells and requires the specific sequence of repair of clustered DNA lesions. 相似文献
7.
Summary Isolated amphibian (Triturus alpestris) gastrula ectoderm was treated with cyclic nucleotides for 24 h and cultured up to 12 days. Explants treated with$cyclic N6-Monobutyryl-adenosine-35-monophosphate, cyclic Dibutyryladenosine-35-monophosphate and cyclic Dibutyrylguanosine-35-monophosphate in a concentration of 10–3 and 10–5 M did not differentiate into mesoderm- or endoderm-derived tissues. The number of explants with small neural and neuroid structures did not exceed the percentage found in the control series. Inductions could also not be obtained when ectoderm was dissociated prior to the treatment with cyclic nucleotides, or when theophylline (which inhibits phosphodiesterase) was added to the culture medium. The results are discussed with regard to the possible mode of action of the vegetalizing factor. 相似文献
8.
Guanosine 5′-triphosphate (GTP) is the key substrate for biosynthesis of guanosine 5′-diphosphate (GDP)-l-fucose. In this study, improvement of GDP-l-fucose production was attempted by manipulating the biosynthetic pathway for guanosine nucleotides in recombinant Escherichia coli-producing GDP-l-fucose. The effects of overexpression of inosine 5′-monophosphate (IMP) dehydrogenase, guanosine 5′-monophosphate (GMP) synthetase
(GuaB and GuaA), GMP reductase (GuaC) and guanosine–inosine kinase (Gsk) on GDP-l-fucose production were investigated in a series of fed-batch fermentations. Among the enzymes tested, overexpression of Gsk
led to a significant improvement of GDP-l-fucose production. Maximum GDP-l-fucose concentration of 305.5 ± 5.3 mg l−1 was obtained in the pH-stat fed-batch fermentation of recombinant E. coli-overexpressing Gsk, which corresponds to a 58% enhancement in the GDP-l-fucose production compared with the control strain overexpressing GDP-l-fucose biosynthetic enzymes. Such an enhancement of GDP-l-fucose production could be due to the increase in the intracellular level of GMP. 相似文献
9.
Pascal Steullet C. D. Derby 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(2):123-135
The aim of this study was to investigate quality coding of blend ratios of binary mixtures by olfactory receptor cells in
the spiny lobster. Three odorants (adenosine-5′-monophosphate, l-glutamate, and taurine) at 0.1–100 μmol · l−1 and seven blend ratios of each of their binary mixtures at a total concentration of 100 μmol · l−1 were used. The olfactory cells recorded (n = 48) evoked across-neuron patterns for single odorants that were well separated from each other. Across-neuron patterns
varied with stimulus concentration but less than with stimulus type. Blend ratios of the three mixtures evoked across-neuron
patterns that were orderly placed within a continuum between those elicited by the components. Mixture interactions, defined
as a lack of independent effects by a mixture's components, occurred in 25, 24 and 37% of responses to blend ratios of glutamate/taurine,
adenosine-5′-monophosphate/taurine, and glutamate/adenosine-5′-monophosphate, respectively. These mixture interactions did
not have a large enough effect on the across-neuron patterns for the mixtures such they would be novel relative to those of
the single components. These results suggest that despite mixture interactions the quality of individual compounds is not
lost when mixed. This corroborates behavioral studies showing that spiny lobsters have the ability to elementally process
odor mixtures.
Accepted: 23 August 1996 相似文献
10.
Summary Cyclic nucleotide phosphodiesterase in the basal-lateral segment of plasma membranes from proximal tubule cells of the rabbit renal cortex was studied and compared to that in the brush border segment of the plasma membrane. Both adenosine 3,5-monophosphate and guanosine 3,5-monophosphate were hydrolyzed by the basal-lateral membrane, but activity varied differently with the two substrates in a complex concentration-dependent manner. Activity with adenosine 3,5-monophosphate was greater than, equal to, or less than with guanosine 3,5-monophosphate, at concentrations of 1000, 100, and 10 to 1 m, respectively. Basal-lateral membrane phosphodiesterase activities at 1 and 500 m substrate exhibited differential responses to pH, metals, heat, and a heat stable inhibitor. Stimulation by guanosine 3,5-monophosphate and inosine 3,5-monophosphate of adenosine 3,5-monophosphate hydrolysis was found in basal-lateral but not in brush border membranes. This stimulation was potentiated by ethyleneglycol-bis(-aminoethyl ether)N,N-tetraacetic acid and ethylenediaminetetraacetate, inhibited by Triton X-100, and totally blocked by Zn2+. The findings indicate that multiple forms of phosphodiesterase are present in the basal-lateral segment and these differ from the activities in the brush border region of the plasma membrane. The characteristics of (i) allosteric, guanosine 3,5-monophosphate-sensitivity of adensoine 3,5-monophosphate phosphodiesterase, and (ii) relatively high guanosine 3,5-monophosphate phosphodiesterase activity, in basal-lateral membranes, which are also enriched in adenylate and guanylate cyclase, suggest an important physiological role for these phosphodiesterases in the regulation of net production of cyclic nucleotides in the renal cortex. 相似文献
11.
Maria Grazia Santangelo Alfredo Medina-Molner Arthur Schweiger George Mitrikas Bernhard Spingler 《Journal of biological inorganic chemistry》2007,12(6):767-775
Simple copper salts are known to denature poly d(GC). On the other hand, copper complexes of substituted 1,4,7,10,13-pentaazacyclohexadecane-14,16-dione
are able to convert the right-handed B form of the same DNA sequence to the corresponding left-handed Z form. A research program
was started in order to understand why Cu(II) as an aquated ion melts DNA and induces the conformational change to Z-DNA in
the form of an azamacrocyclic complex. In this paper, we present a continuous wave and pulse electron paramagnetic resonance
study of the mononucleotide model system Cu(II)–guanosine 5′-monophosphate . Pulse EPR methods like electron–nuclear double
resonance and hyperfine sublevel correlation spectroscopy provide unique information about the electronic and geometric structure
of this model system through an elaborate mapping of the hyperfine and nuclear quadrupole interactions between the unpaired
electron of the Cu(II) ion and the magnetic nuclei of the nucleotide ligand. It was found that the Cu(II) ion is directly
bound to N7 of guanosine 5′-monophosphate and indirectly bound via a water of hydration to a phosphate group. This set of
experiments opens the way to more detailed structural characterization of specifically bound metal ions in a variety of nucleic
acids of biological interest, in particular to understand the role of the metal–(poly)nucleotide interaction.
Arthur Schweiger died on 4 January 2006. 相似文献
12.
The enzyme adenosine 5′-monophosphate deaminase (AMPD, EC 3.5.4.6) catalyzes the conversion of adenosine 5′-monophosphate
to inosine 5′-mononucleotide (IMP). IMP is generally known as the compound responsible for the umami taste of the edible red alga Porphyra yezoensis Ueda that is known in Japan as nori. Therefore, we suspect that AMPD plays a key role in providing a favorable nori taste. In this study, we undertake the molecular
characterization of nori-derived AMPD. The nori AMPD protein has a molecular mass of 55 kDa as estimated from both gel filtration
and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The calculated molecular mass from the amino acid sequence
deduced from cDNA is 57.1 kDa. The isoelectric point is 5.71. The coding region of AMPD consists of 1,566 bp encoding 522 amino acids and possesses a transmembrane domain and two N-glycosylation sites. The sequence identity of nori AMPD in human and yeast AMPDs was found to be less than 50% and 20% in
DNA and amino acid sequences, respectively. Proline in the conserved motif of [SA]-[LIVM]-[NGS]-[STA]-D-D-P was found to be
converted to glutamate. These results indicate that nori AMPD is a novel type of AMPD. 相似文献
13.
Here, the extracellular interconversion of nucleotides and nucleosides was investigated in rat hippocampal slices and synaptosomes
by an HPLC-UV technique. Adenosine 5′-triphosphate (ATP) was converted to adenosine 5′-diphosphate (ADP), adenosine 5′-monophosphate
(AMP), adenosine, inosine, and hypoxanthine in the slices, whereas ADP elicited parallel and concentration-dependent formation
of ATP and AMP. The specific adenylate kinase inhibitor diadenosine pentaphosphate decreased the rate of decomposition of
ADP and inhibited the formation of ATP. No substantial changes in the interconversion of ADP to ATP and AMP were found in
the presence of dipyridamole, flufenamic acid, the P2 receptor antagonist pyridoxal-5-phosphate-6-azophenyl-2′,4′-disulphonic
acid tetrasodium (PPADS), and the alkaline phosphatase substrate para-nitrophenylphosphate. Negligible levels of nucleotides were generated when uridine 5′-diphosphate (UDP), AMP or adenosine
were used as substrates. Ecto-adenylate kinase activity was also observed in purified synaptosomes. In summary, we demonstrate
the presence of an ecto-adenylate kinase activity in the hippocampus, which is a previously unrecognized pathway that influences
the availability of purines in the central nervous system. 相似文献
14.
Pramod K. Sinha Kedar N. Prasad 《In vitro cellular & developmental biology. Plant》1977,13(8):497-501
Summary Adenosine 3′,5′-cyclic monophosphate (cyclic AMP) phosphodiesterase activity in mouse neuroblastoma cells in culture markedly
increased during exponential growth and reached a maximal level at confluency; whereas guanosine 3′, 5′-cyclic monophosphate
(cyclic GMP) phosphodiesterase activity only slightly but significantly increased under a similar experimental condition.
The increase in cyclic AMP phosphodiesterase activity was blocked by both cycloheximide and dactinomycin, whereas the increase
in cyclic GMP phosphodiesterase was blocked by only cycloheximide. When the confluent cells were replated at low density,
the cyclic nucleotide phosphodiesterase activity decreased; however, when they were plated at high cell density which equaled
confluency, the enzyme activity did not decrease. Unlike cyclic AMP phosphodiesterase activity, cyclic GMP phosphodiesterase
activity did not change significantly in prostaglandin E1-treated cells, but decreased in cells treated with the inhibitor of phosphodiesterase. Like cyclic AMP phosphodiesterase
activity, cyclic GMP phosphodiesterase activity also did not change in cells treated with serum-free medium, X-irradiation,
sodium butyrate and 6-thioguanine.
This work was supported by USPHS NS-09230, and DRG-1273 from Damon Runyon-Walter Winchell Cancer Fund. 相似文献
15.
Thomas P. West 《Antonie van Leeuwenhoek》2010,97(3):307-311
Control of pyrimidine formation was examined in Pseudomonas fulva ATCC 31418. Pyrimidine supplementation lowered pyrimidine biosynthetic pathway enzyme activities in cells grown on glucose
or succinate as a carbon source indicating possible repression of enzyme synthesis. Pyrimidine limitation experiments were
conducted using an orotidine 5′-monophosphate decarboxylase mutant strain isolated in this study. Compared to uracil-supplemented,
glucose-grown mutant cells, pyrimidine limitation of this strain caused aspartate transcarbamoylase, dihydroorotase, dihydroorotate
dehydrogenase and orotate phosphoribosyltransferase activities to increase about 6-, 13-, 3-, 15-fold, respectively, which
confirmed regulation of enzyme synthesis by pyrimidines. At the level of enzyme activity, transcarbamoylase activity in Ps. fulva was strongly inhibited by pyrophosphate, CTP, GTP and GDP under saturating substrate concentrations. 相似文献
16.
Usuda Yoshihiro Shimaoka Megumi Kawasaki Hisashi Utagawa Takashi 《World journal of microbiology & biotechnology》2011,27(3):709-712
The guanosine-inosine kinase gene (gsk) isolated from Exiguobacterium acetylicum was expressed in an ATP-regenerating strain, Corynebacterium ammoniagenes. In order to induce its expression, three promoters (those for the Escherichia coli tac, Escherichia coli trp, and Corynebacterium glutamicum odhA gene) with the corresponding ribosome-binding sequences were examined. The E. coli trp promoter was most efficient with regard to inducing the expression of gsk in C. ammoniagenes. Further, the resulting strain, which has both inosine kinase activity and ATP-regenerating activity, was used to induce
the phosphorylation of inosine to produce inosine 5′-monophosphate (5′-IMP), which is widely used as a flavor enhancer; approximately
80 g of 5′-IMP/l was produced with a molar conversion ratio of 80%. 相似文献
17.
18.
The enzymes flavonoid 3′-hydroxylase (F3′H) and flavonoid 3′,5′-hydroxylase (F3′5′H) play an important role in flower color
by determining the B-ring hydroxylation pattern of anthocyanins, the major floral pigments. F3′5′H is necessary for biosynthesis
of the delphinidin-based anthocyanins that confer a violet or blue color to most plants. Antirrhinum majus does not produce delphinidin and lacks violet flower colour while A. kelloggii produces violet flowers containing delphinidin. To understand the cause of this inter-specific difference in the Antirrhinum genus, we isolated one F3′H and two F3′5′H homologues from the A. kelloggii petal cDNA library. Their amino acid sequences showed high identities to F3′Hs and F3′5′Hs of closely related species. Transgenic
petunia expressing these genes had elevated amounts of cyanidin and delphinidin respectively, and flower color changes in
the transgenics reflected the type of accumulated anthocyanidins. The results indicate that the homologs encode F3′H and F3′5′H,
respectively, and that the ancestor of A. majus lost F3′5′H activity after its speciation from the ancestor of A. kelloggii. 相似文献
19.
Concentrations of cAMP (cyclic adenosine 3′,5′-monophosphate) and cGMP (cyclic guanosine 3′,5′-monophosphate), in ganglia from the garden snail Helix pomatia, vary considerably over the course of the day. There is a maximum in the concentration of both cyclic nucleotides between 08:00 and 12:00 (lights on 06:00 to 18:00), with the cAMP maximum occurring slightly later than that in cGMP. In addition there can be several smaller maxima in cAMP and cGMP levels; the timing of these can be markedly different from experiment to experiment, with cAMP and cGMP sometimes in and sometimes out of phase with each other. This pattern is observed in Helix which had been activated from the dormant state 4–6 days earlier, but is not present in dormant or in long-active animals. The cyclic nucleotide rhythm can be seen in ganglia maintained in organ culture, and persists for at least 24 hours after removal of the tissue from the animal. There appears to be little change in the level of basal or Na Fstimulated adenylate cyclase activity in Helix ganglia over the course of the day. On the other hand, both cAMP and cGMP phosphodiesterase activities exhibit rhythms which are consistent with the rhythms in cAMP and cGMP concentrations. 相似文献
20.
M. A. Ivanov G. S. Ludva A. V. Mukovnya S. N. Kochetkov V. L. Tunitskaya L. A. Alexandrova 《Russian Journal of Bioorganic Chemistry》2010,36(4):488-496
4′-Fluoro-2′,3′-O-isopropylidenecytidine was synthesized by the treatment of 5′-O-acetyl-4′-fluoro-2′,3′-O-isopropylideneuridine with triazole and 4-chlorophenyl dichlorophosphate followed by ammonolysis. The interaction of 4′-fluoro-2′,3′-O-isopropylidenecytidine with hydroxylamine resulted in 4′-fluoro-2′,3′-O-isopropylidene-5′-O-acetyl-N
4-hydroxycytidine. The removal of the 2′,3′-O-isopropylidene groups led to acetyl derivatives of 4′-fluorouridine, 4′-fluorocytidine, and 4′-fluoro-N
4-hydroxycytidine. 4′-Fluorouridine 5′-O-triphosphate was obtained in three steps starting from 4′-fluoro-2′,3′-O-isopropylideneuridine. 4′-Fluorouridine 5′-O-triphosphate was shown to be an effective inhibitor of HCV RNA-dependent RNA polymerase and a substrate for the NTPase reaction
catalyzed by the HCV NS3 protein, the hydrolysis rate being similar to that of ATP. It could also activate a helicase reaction
with an efficacy of only threefold lower than that for ATP. 相似文献