共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary 3(2)-O-glycyl-adenosine-5-monophosphate is an intermediate in the conversion of N-[imidazolyl-(1)-carbonyl]-glycine to diketopiperazine in the presence of adenosine-5-monophosphate. The significance of these observations to prebiotic chemistry is discussed.Abbreviations AMP
adenosine-5-monophosphate
- A
adenosine 相似文献
2.
Purified myelin from fresh calf brain white matter was subfractionated in a discontinuous sucrose gradient; significant recovery of protein and 2,3-cyclic nucleotide 3-phosphohydrolase (CNP) and 5-nucleotidase (5N) activities occurred in all three obtained subfractions, the highest recovery being in the light subfraction; highest 5N and CNP specific activities were in medium myelin. Purified myelin was also subfractionated in a continuous sucrose gradient, with a similar localization of protein; CNP activity and 5N activity maxima suggest that myelin may be a predominant locus of 5N in bovine brain white matter. Freezing of brain white matter caused an increase in protein and in CNP and 5N total activity recoveries in denser myelin subfractions. Cytochemistry showed the reaction product of 5N in the whole myelin fraction to be associated with the innermost, outermost and medial compact myelin layers. Effects of non-ionic detergent (Lubrol WX) on 5N activity were studied, and the results also suggest the intrinsic nature of 5N as an ectoenzyme in myelin membranes. Lubrol WX was viewed as an advisable detergent for the stimulation of myelin 5N activity, but not for the solubilization of this enzyme. 相似文献
3.
Ya-Ping Tsao Lian-Yong Wang Shang-Te Hsu Moti L. Jain Shan-Ho Chou Wen-Chang Huang Jya-Wei Cheng 《Journal of biomolecular NMR》2001,21(3):209-220
The solution structure and hydration of a DNARNA hybrid chimeric duplex [d(CGC)r(amamam)d(TTTGCG)]2 in which the RNA adenines were substituted by 2-O-methylated riboadenines was determined using two-dimensional NMR, simulated annealing, and restrained molecular dynamics. Only DNA residue 7T in the 2-OMe-RNA DNA junction adopted an O4-endo sugar conformation, while the other DNA residues including 3C in the DNA 2-OMe-RNA junction, adopted C1-exo or C2-endo conformations. The observed NOE intensity of 2-O-methyl group to H1 proton of 4am at the DNA 2-OMe-RNA junction is much weaker than those of 5am and 6am. The 2-O-methyl group of 4am was found to orient towards the minor groove in the trans domain while the 2-O- methyl groups of 5am and 6am were found to be in the gauche (+) domain. In contrast to the long-lived water molecules found close to the RNA adenine H2 and H1 protons and the methyl group of 7T in the RNA-DNA junction of [d(CGC)r(aaa)d(TTTGCG)]2, there were no long-lived water molecules found in [d(CGC)r(amamam)d(TTTGCG)]2. This is probably due to the hydrophobic enviroment created by the 2-O-methylated riboadenines in the minor groove or due to the wider minor groove width in the middle of the structure. In addition, the 2-O-methylation of riboadenines in pure chimeric duplex increses its melting temperature from 48.5°C to 51.9°C. The characteristic structural features and hydration patterns of this chimeric duplex provide a molecular basis for further therapeutic applications of DNARNA hybrid and chimeric duplexes with 2-modified RNA residues. 相似文献
4.
Isopropylidenation of lactose with 2,2-dimethoxypropane in the presence ofp-toluenesulfonic acid gave two products, which were identified by1H- and13C-NMR as 2,35,63,4-tri-O-isopropylidenelactose dimethyl acetal (1) and its 6-O-(2-methoxy)-isopropyl derivative (2). These products were used for the synthesis of 2-O-methyllactose (7), 2,6-di-O-methyllactose (9) and 2-O-benzyllactose (13). 相似文献
5.
Lai-Xi Wang Nadejda V. Pavlova Su-Chen Li Yu-Teh Li Yuan C. Lee 《Glycoconjugate journal》1996,13(3):359-365
4-Methylumbelliferyl 6-O-benzyl--d-lactoside (6Bn-MU-Lac) and some related compounds were synthesizedvia different selective reactions including phase-transfer glycosylation. Their suitability as substrates for a fluorometric assay of ceramide glycanase (CGase) was evaluated. Among others, the 6Bn-MU-Lac, which is resistant to exogalactosidase, was found to be a suitable substrate for routine assay of the CGase activity. For American leech CGase, theK
m value is 0.232 mM at pH 5.
Abbreviations: CGase, ceramide glycanase; Gal, galactose; Glc, Glucose; Lac, lactose; MU, 4-methylumbelliferone; MU-Lac, 4-methylumbelliferyl -d-lactoside; bBn-Lac, 6-O-benzyl-lactose; 6Bn-MU-Lac, 4-methylumbelliferyl 6-Obenzyl--d-lactoside; 46Bd-MU-Lac, 4-methylumbelliferyl 4,6-O-benzylidene--d-lactoside; MU-Cel, 4-methylumbellifery -d-cellobioside; 46Bd-MU-Cel, 4-methylumbelliferyl 4,6-O-benzylidene--d-cellobioside; TLC, thin layer chromatography;1H-NMR, proton nuclear magnetic resonance; GSL, glycosphingolipids; CSA, 10-camphorsulfonic acid. See Scheme 1 for chemical structures. 相似文献
6.
Summary 2-Amino-2-deoxyuridine reacts efficiently with nucleoside 5-phosphorimidazolides in aqueous solution. The dinucleoside monophosphate analogues were obtained in yields exceeding 80% under conditions in which little reaction occurs with the natural nucleosides.In a similar way, the 5-phosphorimidazolide of 2-amino-2-deoxyuridine undergoes self-condensation in aqueous solution to give a complex mixture of oligomers.The phosphoramidate bond in the dinucleoside monophosphate analogues is stable for several days at room temperature and pH 7. The mechanisms of their hydrolysis under acidic and alkaline conditions are described.Abbreviations A
adenosine
- C
cytidine
- G
guanosine
- U
uridine
- T
thymidine
- UN
3
2-azido-2-deoxyuridine
- UNH
2
2-amino-2-deoxyuridine
- ImpA
adenosine 5-phosphorimidazolide
- ImpU
uridine 5-phosphorimidazolide
- ImpUN
3
2-azido-2-deoxyuridine 5-phosphorimidazolide
- ImpUNH
2
2-amino-2-deoxyuridine 5-phosphorimidazolide
- pA
adenosine 5-phosphate
- pU
uridine 5-phosphate
- pUN
3
2-azido-2-deoxyuridine 5-phosphate
- pUNH
2
2-amino-2-deoxyuridine 5-phosphate
- UpA
uridylyl-[35]-adenosine
- UpU
uridylyl-[35]-uridine
- UNpA
adenylyl-[52]-2-amino-2-deoxy-uridine
- UNpU
uridylyl-[52]-2-amino-2-deoxyuridine (pUN)n n=2,3,4 [25]-linked oligomers of pUNH
2 poly(A) polyadenylic acid
- Im
imidazole
- MeIm
l-methylimidazole 相似文献
7.
Kucher V. V. Rozhmanova O. M. Pogorelaya N. Kh. Dolgaya E. V. Magura I. S. 《Neurophysiology》2001,33(3):148-152
We studied modulating influences of a core oligoadenylate, 2,5-ApApA, on the voltage-operated potassium channels; the agent was injected into cloned cells of the rat pheochromocytoma PC-12. Diffusion of 2,5-ApApA from a micropipette into the cell evoked clear changes in the current-voltage relationships of the integral potassium current; when positive shifts of the membrane potential reached about +20 mV, a saturation phenomenon was observed. The dependence of the probability for open state of the voltage-operated potassium channels on the membrane potential was calculated using normalization of the potassium conductance graphs; it satisfactorily fit Boltzmann's equation. Under the influence of 2,5-ApApA, activation of the potassium channels became more strongly dependent on the voltage. Within the first minutes of the action of core oligoadenylate, the potassium conductance changed by e times at a shift of the membrane potential by 12 mV, while after a stationary level of the 2,5-ApApA effect had been attained (approximately from the 25th min), the same change in the potassium conductance needed only an 8-mV shift. We conclude that 2,5-ApApA-evoked conformation modifications in the structure of the potassium channels in the cells of rat PC-12 pheochromocytoma can result from an increase in the sensitivity of voltage sensors in the above-mentioned channels to changes in the membrane potential. 相似文献
8.
Ahlert Schmidt 《Archives of microbiology》1977,112(3):263-270
Crude extracts of Rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (35S) sulfate, (35S) adenosine-5-phosphosulfate, and (35S) 3-phosphoadenosine-5-phosphosulfate. An enzyme fraction similar to APS-sulfotransferases from plant sources was purified 228-fold from Rhodospirillum rubrum. It is suggested here that this enzyme is specific for adenosine-5-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5-phosphosulfate, however, only at a rate of 1/10 of that with adenosine-5-phosphosulfate. Further, the reaction with 3-phosphoadenosine-5-phosphosulfate was inhibited with 3-phosphoadenosine-5-phosphate whereas this nucleotide had no effect on the reaction with adenosine-5-phosphosulfate. For this activity with adenosine-5-phosphosulfate the name APS-sulfotransferase is suggested. This APS-sulfotransferase needs thiols for activity; good rates were obtained with either dithioerythritol or reduced glutathione; other thiols like cysteine, 2-3-dimercaptopropanol or mercaptoethanol are less effective. The electron donor methylviologen did not catalyze this reaction. The pH-optimum was about 9.0; the apparent K
m for adenosine-5-phosphosulfate was determined to be 0.05 mM with this so far purified enzyme fraction. Enzyme activity was increased with K2SO4 and Na2SO4 and was inhibited by 5-AMP. These properties are similar to assimilatory APS-sulfotransferases from spinach and Chlorella.Abbreviations APS
adenosine-5-phosphosulfate
- PAPS
3-phosphoadenosine-5-phosphosulfate
- 5-AMP
adenosine-5-monophosphate
- 3-AMP
adenosine-3-monophosphate
- 3-5-ADP
3-phosphoadenosine-5-phosphate (PAP)
- DTE
dithiorythritol
- GSH
reduced glutathione
- BAL
2-3-dimercaptopropanol 相似文献
9.
Yuxi Pang Lei Zeng Alexander V. Kurochkin Erik R.P. Zuiderweg 《Journal of biomolecular NMR》1998,11(2):185-190
A new triple-resonance pulse sequence, 3D HNHCACO, is introduced and discussed, which identifies sequential correlations of the backbone nuclei (H(i-1), C(i-1), C(i-1), NH(i)) of doubly labeled proteins in H2O. The three-dimensional (3D) method utilizes a recording of 15N and 13C resonances in a single indirect time domain, the 13C resonance in another indirect time domain, and detects both NH and H protons. A bidirectional coherence transfer (NH(i) N(i) C(i-1) C(i-1) H(i-1)) is effectuated, resulting in a single high-resolution 3D spectrum that contains the frequencies of all five backbone nuclei. The experiment was applied to the 12.3 kDa ribonuclease from Bacillus intermedius (Binase). 相似文献
10.
Rafael Alvarez-Gonzalez 《Molecular and cellular biochemistry》1994,138(1-2):213-219
Recently, two deoxyribose analogs of NAD+ (2-deoxy and 3-deoxyNAD+) have been synthesized and purified in this laboratory. Whereas 2-deoxyNAD+ was an efficient substrate for arg-specific mon(ADP-ribosyl) transferases, it was not a substrate for poly(ADP-ribose) polymerase (PARP). Instead, it was a non-competitive inhibitor of NAD+ in the ADP-ribose polymerization reaction catalyzed by PARP. Thus, 2-deoxyNAD+ has been utilized to distinguish between mono(ADP-ribose) and poly(ADP-ribose) acceptor proteins. 2-deoxyNAD+ has also been used to characterize the arg-specific mono(2-deoxyADP-ribosyl)ation reaction of PARP with cholera toxin or avian mono(ADP-ribosyl)transferase. By contrast, 3-deoxyNAD+ can effectively be utilized as a substrate by PARP. However, while the estimated Km and Kcat of polymerization with 3-deoxyNAD+ can were 20 M and 0.11 moles/sec, the Km and Kcat with NAD+ as a substrate were 59 M and 1.29 moles/sec, respectively. Determination of the average size of 3-deoxyADP-ribose polymers indicated that chains no larger than four residues are synthesized with this substrate. Thus, the utilization of 3-deoxyNAD+ has facilitated the electrophoretic identification of poly(ADP-ribose) acceptor proteins in mammalian chromatin. 相似文献
11.
DNA polymerases II () and III() are the only nuclear DNA polymerases known to possess an intrinsic 3 5 exonuclease in Saccharomyces cerevisiae. We have investigated the spontaneous mutator phenotypes of DNA polymerase and 3 5 exonuclease-deficient mutants, pol3-01 and pol2-4, respectively. pol3-01 and pol2-4 increased spontaneous mutation rates by factors of the order of 102 and 101, respectively, measured as URA3 forward mutation and his7-2 reversion. Surprisingly, a double mutant pol2-4 pol3-01 haploid was inviable. This was probably due to accumulation of unedited errors, since a pol2-4/pol2-4 pol3-01/pol3-01 diploid was viable, with the spontaneous his7-2 reversion rate increased by about 2 × 103-fold. Analysis of mutation rates of double mutants indicated that the 3 5 exonucleases of DNA polymerases and can act competitively and that, like the 3 5 exonuclease of DNA polymerase the 3 5 exonuclease of DNA polymerase acts in series with the PMS1 mismatch correction system. Mutational spectra at a URA3 gene placed in both orientations near to a defined replication origin provided evidence that the 3 5 exonucleases of DNA polymerases and act on opposite DNA strands, but were in sufficient to distinguish conclusively between different models of DNA replication. 相似文献
12.
S. V. Vasil'eva T. V. Abramova T. M. Ivanova G. V. Shishkin V. N. Sil'nikov 《Russian Journal of Bioorganic Chemistry》2004,30(3):234-242
A convenient preparative synthesis of 2-amino-2-deoxyuridine was developed. Starting from 2-amino-2-deoxyuridine and 2-amino-2-deoxycytidine, monomers for the phosphoamidite oligonucleotide synthesis were obtained that carry a linker with methoxyoxalamide groups in position 2. 相似文献
13.
Summary We have studied the reactions between adenosine 5-phosphorimidazolide and 9-(2-amino-2-deoxyxylofuranosyl) adenine (I) or 3-methylamino-3-deoxyadenosine (II), both with and without a poly (U) template. We find that both amino compounds react much more rapidly than does adenosine, in the absence of a template. The rate of reaction is greatly enhanced by a poly (U) template in the case of I, but the enhancement is slight in the case of II.Abbreviations A
adenosine
- xylo ANH2
9-(2-amino-2-deoxy--D-xylofuranosyl) adenine
- ANHMe
3-methylamino-3-deoxyadenosine
- ImpA
adenosine 5-phosphorimidazolide
- A3 pA
adenylyl-[35]-adenosine
- A2 pA
adenylyl-[25]-adenosine
- UNPA
adenylyl-[52]-2-amino-2-deoxyuridine
- xylo ANPA
9-[adenylyl-(52)-2-amino-2-deoxy--D-xylofuranosyl]adenine
- A(NMe)pA
adenylyl-[53]-3-methylamino-3-deoxyadenosine
- pA
adenosine 5phosphate
- AppA
P1, P2-diadenosine 5pyrophosphate
- (pA)n
n = 2, 3 [2-5]-linked oligomers of pA
- A2 pA2 pA
[2-5]-linked trinucleoside diphosphate of A
- poly (U)
polyuridylic acid 相似文献
14.
A model is proposed for the effect of gramicidin A on the order and structure of phospholipid dispersions. According to this model, the addition of gramicidin A influences the surrounding lipids via two independent mechanisms. The first arises from a drop in surface pressure for those lipids substantially bounded by gramicidin A. The second mechanism arises from the increase in the phospholipid headgroup spacing due to the small polar region of the polypeptide. The model provides an explanation for the currently available NMR, X-ray diffraction and Langmuir monolayer results. The model also suggests mechanisms for the ability of gramicidin A to trigger a transition of the lipid from the lamellar to hexagonal II phase, the dependence of this transition on the lipid chain length and the formation of a lamellar phase with lysophosphatidylcholine.Abbreviations NMR
nuclear magnetic resonance
- DMPC
dimyristoylphosphatidylcholine
- S
molecular order parameter
- CSA
chemical shift anisotropy
- DPPC
dipalmitoylphosphati-dylcholine
- LPC
lysophosphatidylcholine 相似文献
15.
Summary Organic pyrophosphates such as UppA and NAD are formed when a solution containing a nucleotide, a nucleoside 5-polyphosphate, Mg2+ and imidazole are allowed to dry out. We suggest that this synthesis may have occured concurrently with oligonucleotide formation.Abbreviations Im
Imidazole
- CDI
1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride
- EDTA
ethylenediaminetetraacetic acid
- A
adenosine
- U
uridine
- pnA
adenosine 5-poly-phosphate containing n phosphate residues
- pU
uridine 5-phosphate
- AppA
P1,P2-diadenosine 5-pyrophosphate
- UppA
P1-(uridine 5)-P2-(adenosine 5)-pyrophosphate
- ImpA
adenosine 5-phosphorimidazolide
- NMN
nicotinamide mononucleotide
- NAD
nicotinamide-adenine dinucleotide 相似文献
16.
Bacteria, yeasts, and molds which grew in a medium containing a synthetic lignin — a dehydrogenation polymer (DHP) of coniferyl alcohol — as a sole carbon source, were isolated from soil. One fungus, Fusarium solani M-13-1, was found to degrade the DHP most vigorously among the isolated organisms. It was shake-cultured in a medium containing dehydrodiconiferyl alcohol (DHCA) (I), an important lignin model compound, and the following six metabolic products were isolated and identified: 1) Phenylcoumaran--aldehydic (II) and -carboxylic compounds, 2) phenylcoumaran--aldehydic compound (IV), formed by release of a 2-carbon fragment from the phenylcoumaran--carboxylic compound, 3) 5-acetylvanillyl alcohol (V), formed by cleavage of the coumaran ring and reduction of the -aldehyde group, 4) 5-carboxyvanillyl alcohol (VI), formed by subsequent oxidation of the acetyl group, and 5) the -ether of DHCA (VII), considered to be a by-product. A degradation pathway for DHCA was proposed on the basis of these metabolic products.Non-Standard Abbreviations DHP
dehydrogenation polymer
- DHCA
dehydrodiconiferyl alcohol
- DDQ
dichlorodicyano-p-benzoquinone
- DDHQ
dichlorodicyano-p-hydroquinone
- Ar
aromatic
- TLC
thin layer chromatography
- GC-MS
gas chromatography-mass spectrometry 相似文献
17.
Sombutyanuchit P. Suphantharika M. Verduyn C. 《World journal of microbiology & biotechnology》2001,17(2):163-168
Spent brewer's yeast was autolysed and used as a raw material for the preparation of 5-GMP-rich yeast extracts. Malt rootlets were used as a source of 5-phosphodiesterase. The crude enzyme was extracted from malt rootlets and pretreated to inactivate 5-nucleotidase. The optimum pretreatment conditions were heating at 65 °C for 30 min or 70 °C for 7 min. The effects of autolysis time, phosphodiesterase concentration and incubation period on 5-GMP content were examined. The suitable autolysis time was 8 h. The preferable enzyme treatment period was in the range of 8–14 h. Longer autolysis and enzyme incubation periods caused a decrease in the 5-GMP content from 0.7–0.9% (w/w) to 0.2–0.4% (w/w). The 5-GMP content in extracts from debittered and non-debittered yeast was similar. The highest 5-GMP content in yeast extract was 0.93% (w/w), obtained with a phosphodiesterase concentration of 1.6unit/ml of yeast extract (5% solids content). 相似文献
18.
Akio Katayama Haruko Ogawa Kenji Kadomatsu Nobuyuki Kurosawa Takaaki Kobayashi Norio Kaneda Kenji Uchimura Itsuo Yokoyama Takashi Muramatsu Hiroshi Takagi 《Glycoconjugate journal》1998,15(6):583-589
Full length cDNA and genomic DNA of porcine -1,3-galactosyltransferase were isolated, and their structures were analysed. The coding region was encoded by six exons as in the mouse, and the length of each exon was conserved between the two species. The porcine exons were designated Exon 4–9, since in the mouse coding exons started from Exon 4. Introns tended to be longer in the porcine gene; the distance from Exon 4 to the 3-end of Exon 9 was 24 kb, while this region was 18 kb in the mouse gene. The cDNA structure was extended from the previous data to the 3-end and to the 5 side of the cDNA. In addition to a cDNA clone with all coding exons, clones lacking parts of these exons were isolated and their structures were determined. One variant lacked Exon 5; the second, Exons 5 and 6; and the third, Exons 5, 6 and 7. The last variant was not found in the mouse, and cDNA transfection of this variant yielded scarcely any enzymatic activity using asialo 1-acid glycoprotein as a substrate, and decreased activity using N-acetyllactosamine as a substrate. 相似文献
19.
R. Lohrmann 《Journal of molecular evolution》1977,10(2):137-154
Summary Adenosine 5-phosphoramidates form when solutions containing adenosine 5-polyphosphates pnA (n 3) or P1, P2-diadenosine 5-diphosphate and amines are allowed to dry out. Mg ions catalyze these reactions. We have studied systems containing ammonia, imidazole, glycine, ethylenediamine and histamine. The yields of adenosine 5-phosphoramidates range from 10–50 % based on the nucleotide. The prebiotic significance of the reactions is discussed.Abbreviations Im
imidazole
- hist
histamine
- gly
glycine
- en
ethylenediamine
- CDI
1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride
- EDTA
ethylenediaminetetraacetic acid
- A
adenosine
- Pn (n = 1, 2 )
linear polyphosphate containing n phosphate residues
- pnA
adenosine 5-polyphosphate containing n phosphate residues
- ADP
adenosine 5-diphosphate
- ATP
adenosine 5-triphosphate
- AppA
P1, P2-diadenosine 5-diphosphate
- gly-pA
adenylyl-(5N)-glycine
- ImpA
adenosine 5-phosphorimidazolide
- NH2-pA
adenosine 5-phosphoramidate
- en-pA
adenylyl-(5N)-ethylenediamine
- hist (NH) - pA
adenosine 5-phospho-[2-(4-imidazolyl)-ethylamide]
- hist(Im)-pA
adenosine 5-phospho-[4-(2-aminoethyl)-imidazolide]
- enP1,2
phosphoramidates of ethylenediamine derived from H3PO4 and H4P2O7 相似文献
20.
Chong D.K.X. Roberts W. Arakawa T. Illes K. Bagi G. Slattery C.W. Langridge W.H.R. 《Transgenic research》1997,6(4):289-296
A 1177 bp cDNA fragment encoding the human milk protein -casein was introduced into Solanum tuberosum cells under control of the auxin-inducible, bidirectional mannopine synthase mas12) promoters using Agrobacterium tumefaciens-mediated leaf disc transformation methods. Antibiotic-resistant plants were regenerated and transformants selected based on luciferase activity carried by the expression vector containing the human -casein cDNA. The presence of human -casein cDNA in the plant genome was detected by PCR and DNA hybridization experiments. Human -casein mRNA was identified in leaf tissues of transgenic plants by RT-PCR analysis. Human - casein was identified in auxin-induced leaf and tuber tissues of transformed potato plants by immunoprecipitation and immunoblot analysis. Human -casein produced in transgenic plants migrated in polyacrylamide gels as a single band with an approximate molecular mass of 30 kDa. Immunoblot experiments identified approximately 0.01% of the total soluble protein of transgenic potato leaf tissue as -casein. The above experiments demonstrate the expression of human milk - casein as part of an edible food plant. These findings open the way for reconstitution of human milk inedible plants for replacement of bovine milk in baby foods for general improvement of infant nutrition, and for prevention of gastric and intestinal diseases in children 相似文献