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1.
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
2.
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
3.
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
4.
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
5.
The properties and the regulation of adenosine 5-phosphosulfate sulfotransferase extracted from cell suspension cultures ofNicotiana sylvestris was investigated. Optimal adenosine 5-phosphosulfate sulfotransferase activity was obtained from the cells by extraction with 0.1 M tris-HCl, pH8.0, containing 2 M MgSO4 and 10 mM dithioerythritol. The K
m
for adenosine 5-phosphosulfate in the sulfotransferase reaction was about 11 M. Adenosine 5-phosphosulfate in concentrations above 50 M were inhibitory. The extratable adenosine 5-phosphosulfate sulfotransferase activity decreased during cultivation with sulfate as the sole sulfur source, but after about 3 days it reached a constant level (50 to 100 nmol activated sulfate transferred h-1 mg-1 protein) which was maintained for at least 24 h. Addition of 0.5 mM cysteine to the culture medium decreased the extractable adenosine 5-phosphosulfate sulfotransferase activity and blocked growth completely. With 0.1 mM cysteine an enzyme level of about 10% of the initial value was reached within 6 to 12 h without significant inhibition of growth. The added cysteine was absorbed rapidly and after 24 h cysteine could no longer be detected in the medium. Before the cysteine was completely depleted, the activity of adenosine 5-phosphosulfate sulfotransferase started to increase, reaching ultimately a level which was comparable to the initial value.Abbreviations APS
Adenosine 5-phosphosulfate
- APSSTase
adenosine 5-phosphosulfate sulfotransferase
- DTE
dithioerythritol
- PAPS
adenosine 3-phosphate 5-phosphosulfate
- 2,4-D
2,4-di-chlorophenoxyacetic acid
- BAP
benzyladenine
This paper is no. 10 in the series Regulation of Sulfate Assimilation in Plants. 相似文献
6.
The gene encoding 5 3 exonuclease domain-deleted Tfi DNA polymerase, named 5 3 Exo–
Tfi fragment, from Thermus filiformis was expressed in Escherichia coli under the control of the tac promoter on a high-copy plasmid, pJR. The expressed enzyme was purified 27-fold with a 19% yield and a specific activity of 2621 U mg–1 protein. The 5 3 exonuclease domain of Tfi DNA polymerase was removed without significant effect on enzyme activity and stability. PCR conditions for the 5 3 Exo–
Tfi fragment were more tolerant to the buffer composition as compared to the full-length enzyme. 相似文献
7.
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
8.
Summary Soluble lead salts and a number of lead-containing minerals catalyze the formation of oligonucleotides from nucleoside 5-phosphorimidazolides. The effectiveness of lead compounds correlates strongly with their solubility. Under optimal conditions we were able to obtain 18% of pentamer and higher oligomers from ImpA. Reactions involving ImpU gave smaller yields.Abbreviations A
adenosine
-
U
uridine
-
Im
imidazole
-
MeIm
1-methyl-imidazole
-
EDTA
ethylenediaminetetraacetic acid
-
pA
adenosine 5-phosphate
-
pU
uridine 5-phosphate
-
Ap
adenosine cyclic 2:3-phosphate
-
ATP
adenosine 5-triphosphate
-
AppA
P1,P2-diadenosine 5-diphosphate
-
pNp (N = A,U)
nucleotide 2(3), 5-diphosphate
-
ImpA
adenosine 5-phosphoreimidazolide
-
ImpU
uridine 5-phosphorimidazolide
-
A
2pA
adenylyl-[25]-adenosine
-
A
3pA
adenylyl-[35]-adenosine
-
pA
2pA
5-phospho-adenylyl-[25]-adenosine
-
pA
3pA
5-phospho-adenylyl-[35]-adenosine
-
pUpU
5-phospho-uridylyl-uridine
-
pApU
5-phospho-adenylyl-uridine
-
pUpA
5-phospho-uridylyladenine
-
(pA)n (n, 2,3,4,)
oligoadenylates with 5 terminal phosphate
-
ImpApA
5-phosphorimidazolide of adenylyl adenosine
-
(pA)
5+
pentamer and higher oligoadenylates with 5 terminal phosphate
-
(Ap)nA (n = 2,3,4)
oligoadenylates without terminal phosphates
In the following we do not specify the nature of the internucleotide linkageIn the following we do not specify the nature of the internucleotide linkage 相似文献
9.
R. Lohrmann 《Journal of molecular evolution》1975,6(4):237-252
Summary When solutions of nucleoside 5-phosphates and trimetaphosphate are dried out at room temperature, nucleoside 5-polyphosphates are formed. The Mg++ ion shows a superior catalytic function in this reaction when compared with other divalent metal ions. Starting with nucleoside 5-phosphates, Mg++ and trimetaphosphate, the predominant products in the nucleoside 5-polyphosphate series pnN are p4N, p7N and P10N. Nucleoside 5-diphosphates yield p5N and p8N, nucleoside 5-triphosphates give p6N and p9N. The prebiological relevance of these reactions is discussed.Abbreviations Pn (n = 1,2,3,)
linear polyphosphate containing n phosphate residues
- P3!
trimetaphosphate
- A
adenosine
- U
uridine
- dA
2-dexyadenosine
- T
thymidine
- PnN
nucleoside 5-polyphosphate containing n phosphate residues, e.g. with N = A and n = 4
- p4A
adenosine 5-tetraphosphate 相似文献
10.
Roots of spinach (Spinacia oleracea L.) seedlings contained only a very low activity of adenosine 5-phosphosulfate sulfotransferase compared to the cotyledons. Adenosine 5-phosphosulfate sulfotransferase activity increased about tenfold in cotyledons during greening. Preparation of organelle fractions from spinach leaves by a combination of differential and isopycnic density gradient centrifugation showed that adenosine 5-phosphosulfate sulfotransferase banded with NADP-glyceraldehyde-3-phosphate dehydrogenase, a marker enzyme for intact chloroplasts. In the fractions of peroxisomes, mitochondria and broken chloroplasts virtually no adenosine 5-phosphosulfate sulfotransferase activity was measured. Comparison with the chloroplast enzyme NADP-glyceraldehyde-3-phosphate dehydrogenase indicates that in spinach, adenosine 5-phosphosulfate sulfotransferase is localized almost exclusively in the chloroplasts.Abbreviations APS
Adenosine 5-phosphosulfate
- APSSTase
Adenosine 5-phosphosulfate sulfotransferase
- BSA
Bovine serum albumin
- BRIJ58
Polyethylene glycolmonostearylether
- DTE
Dithioerythritol
- DTT
Dithiothreitol
- EDTA
Ethylenediaminetetraacetic acid
- ME
2-Mercaptoethanol
- NADP-GPD
NADP-linked glyceraldehyde-3-phosphate dehydrogenase
- PAPS
Adenosine 3-phosphate 5-phosphate 5-phosphosulfate
- POPOP
1,4 Di [2-(5-phenyloxazolyl)]-benzene
- PPO
2,5-Diphenyloxazol
The results presented in this paper are taken from the Ph. D. thesis of H.F. 相似文献
11.
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
12.
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
13.
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
14.
When Lemna minor L. is transferred to an atmosphere with H2S, there is a rapid loss of extractable adenosine-5-phosphosulfate sulfotransferase activity. The activity is restored within 24 h in an atmosphere without H2S. This restoration of activity is completely inhibited by cycloheximid but not by chloramphenicol. In vitro, S2- up to 5 mM and cysteine, methionine, and glutathione up to 50 mM do not inhibit the enzyme. The activities of ATP sulfurylase and O-acetyl-L-serine sulfhydrylase are not affected significantly by H2S. The physiological significance of the regulation of adenosine-5-phosphosulfate sulfotransferase is discussed.Abbreviations APS
adenosine-5-phosphosulfate
- PAPS
adenosine-3-phosphate-5-phosphosulfate
- BSA
bovine serum albumin
- DTT
dithiothreitol
- POPOP
1,4-di [2-(5-phenyloxazolyl)]-benzene
- PPO
2,5-diphenyloxazol
This is no. 6 in the series Regulation of Sulfate Assmilation in Plants 相似文献
15.
The white rot basidiomycete Phanerochaete chrysosporium metabolized 1-(3,4-diethoxyphenyl)-1,3(dihydroxy)-2-(4'-methoxyphenyl)-propane (XII) in low nitrogen stationary cultures, conditions under which the ligninolytic enzyme system is expressed. 3,4-Diethoxybenzyl alcohol (IV), 1,2(dihydroxy)-1-(4-methoxyphenyl)ethane (XX) and anisyl alcohol were isolated as metabolic products indicating an initial , bond cleavage of this dimer. Exogenously added XX was rapidly converted to anisyl alcohol, indicating that XX is an intermediate in the metabolism of XII. Fungal cleavage of the , bond of 1-(3-4-diethoxyphenyl)-1-(hydroxy)-2-(4'-methoxyphenyl)ethane (XI) also occurred, indicating that a hydroxymethyl group is not a prerequisite for this reaction. P. chrysosporium also metabolized 1-(4-ethoxy-3-methoxyphenyl)-2,2(dihydroxy)-2-(4'-methoxyphenyl)propane-1-ol (XIII). The major products of the degradation of this triol included 4-ethoxy-3-methoxybenzyl alcohol (III) and 2-hydroxy-1-(4-methoxyphenyl)-1-oxoethane (XXI). The nature of the products formed indicates that this triol is also cleaved directly at the , bond. The significant difference in the nature of the products formed from the diaryl propane (XII) and the triol (XIII), however, suggests that XIII is not an intermediate in the major pathway for the degradation of XII. Metabolites were identified after comparison with chemically synthesized standards by GLC-mass spectrometry.Abbreviations GLC
Gas liquid chromatography
- TMSi
trimethylsilyl
- TLC
thin layer chromatography
- MS
mass spectrometry 相似文献
16.
Summary Imidazolides of dinucleotides such as ImpApA can be formed from the corresponding dinucleotides in a two-stage process, which gives up to 15% yields under potentially prebiotic conditions. First a solution of the dinucleotide and sodium trimetaphosphate is dried out at constant temperature and humidity. This produces polyphosphates such as pnApA in excellent yield (80%). The products are dissolved in water, imidazole is added, and the solution is dried out again. This yields the 5-phosphorimidazolides.Abbreviations P3!
trimetaphosphate
- A
adenosine
- U
uridine
- EDTA
ethylenediaminetetraacetic acid
- Ap
adenosine 2(3)-phosphate
- Ap!
adenosine cyclic 2:3-phosphate
- pA
adenosine 5-phosphate
- pA2p
adenosine 2, 5-diphosphate
- pA3p
adenosine 3, 5-diphosphate
- pAp!
5-phospho-adenosine cyclic 2:3-phosphate
- ATP
adenosine 5-triphosphate
- ImpA
adenosine 5-phosphorimidazolide
- A2pA
adenylyl-[25]-adenosine
- A3pA
adenylyl-[35]-adenosine
- A2pU
adenylyl-[25]-uridine
- A3pU
adenylyl-[35]-uridine
- pA2pA
5-phosphoadenylyl-[25]-adenosine
- pA3pA
5-phospho-adenylyl-[35]-adenosine
- pA2pU
5-phospho-adenylyl-[25]-uridine
- pA3pU
5-phospho-adenylyl-[35]-uridine
- pApN (N= A, U)
5-phosphate of a dinucleoside phosphate
- pnApN (N = A, U; n = 2, 3, 4.)
5-polyphosphate of a dinucleoside phosphate
- ImpA2pA
imidazolide of pA2pA
- ImpA3pA
imidazolide of pA3pA
- ImpA2pU
imidazolide of pA2pU
- ImpA3pU
imidazolide of pA3pU
- ImpApN
imidazolide of pApN 相似文献
17.
As a precursor for the chemical synthesis of sialylated oligosaccharides, the trisaccharide glycoside Neu5Ac (2-8)Gal(1-4)GlcNAc(1-O)-pent-4-ene was synthesized starting from GlcNAc(1-O)-pent-4-ene, UDP-glucose andN-acetylneuraminic acid in a one pot reaction employing galactosyltransferase and (2-6)sialyl-transferase in a complete cofactor regeneration system.Abbreviations Neu5Ac
N-acetylneuraminic acid
- CMP-Neu5Ac
cytidine 5-monophosphosialate
- CMP
cytidine 5-monophosphate
- CDP
cytidine 5-diphosphate
- CTP
cytidine 5-triphosphate
- Gal
galactose
- GlcNAc
N-acetylglucosamine
- UDP
uridine 5-diphosphate
- UDP-Glc
uridine-5-diphosphoglucose
- UDP-Gal
uridine-5-diphosphogalactose
- PEP
phosphoenolpyruvate 相似文献
18.
Candida antarctica B lipase-catalysed alcoholysis of 2, 3, 5-tri-O-hexanoyluridine (1a), 2, 3, 5-tri-O-dodecanoyluridine (1b), 2, 3, 5-tri-O-hexanoylinosine (1c) and 2, 3, 5-tri-O-dodecanoylinosine (1d) proceeded regioselectively to produce the corresponding 2, 3-di-O-acylribonucleosides 2a–d, providing a simple and efficient access to these new lipophilic compounds. Contrasting to the alcoholysis, enzymatic hydrolysis of 1a–d using different enzymes and experimental conditions did not proceed regioselectively. 相似文献
19.
Purification and properties of the ATP: adenylylsulphate 3′-phosphotransferase from Chlamydomonas reinhardii 总被引:3,自引:0,他引:3
APS-kinase (ATP: adenylylsulphate 3-phosphotransferase, EC 2.7.1.25) has been purified from the alga Chlamydomonas reinhardii, strain CW 15 by means of chromatofocussing and affinity chromatography. The isolated protein showed an apparent molecular mass of 44,000 upon sodium dodecylsulphate polyacrylamide gel electrophoresis. The transfer of phosphate groups from ATP onto APS required a pH of 6.8, the presence of Mg2+ ions and a reducing thiol. Its catalytical activity was destroyed by sulphhydryl group inhibitors (phenyl-mercuri compounds, dithiopyridine) and alkylating reagents.The purified enzyme attained a V
max of 360 pkat under optimal reaction conditions declining to v
limit of 260 pkat in the presence of excess substrate APS. This sensitivity towards changes in substrate concentrations was parallelled by a high affinity and specificity: apparent K
m APS: 2 · 10-6 mol · l-1, and K
m ATP: 7 · 10-6 mol · l-1. The enzyme was found specific for ATP, d-ATP and CTP, while UTP, ITP and GTP showed marginal activity. The Hill coefficients suggested 4 binding sites for APS and 1 for ATP. Excessive APS resulted in a negative slope indicating 3 inhibiting sites of the substrate.Abbreviations APS
Adenosine 5-phosphosulphate
- dATP
2-deoxyadenosine 5-triphosphate
- p-CMB
p-chloromercuribenzoate
- DTE
dithioerythritol
- DTT
dithiothreitol
- -MSH
-mercaptoethanol
- PAPS
3-phosphoadenosine 5-phosphosulphate
- PAP
3-phosphoadenosine 5-phosphate
- SDS
sodium dodecyl sulphate
This work is part of a dissertation submitted by H. G. J., Bochum 1982 相似文献
20.
During chloroplast development in the primary leaves of Phaseolus vulgaris, the extractable activity of adenosine 5-phosphosulfate sulfotransferase increased ten-fold. When chloroplast development took place in air enriched with 3.5 l H2S·l-1 there was a decrease in adenosine 5-phosphosulfate sulfotransferase activity. Cyst(e)ine in concentrations up to 1 mM (in the external medium) did not affect the increase in adenosine 5-phosphosulfate sulfotransferase activity in intact plants. In plants with excised roots, 0.75 mM cyst(e)ine inhibited this increase. In green primary leaves, H2S or cyst(e)ine treatment resulted in a decrease of extractable adenosine 5-phosphosulfate sulfotransferase activity. In intact plants, this effect of cyst(e)ine was observed at a concentration of 1 mM, and in plants with excised roots, 0.25 mM had a comparable effect.In developing plants, the extractable activities of O-acetyl-L-serine sulfhydrylase (EC 4.2.99.9) and ribulosebisphosphate carboxylase (EC 4.1.1.39.) were not affected by H2S or cyst(e)ine.Abbreviations APS
adenosine 5-phosphosulfate
- APSSTase
adenosine 5phosphosulfate sulfotransferase
- BSA
bovine serum albumin
- DTE
dithioerythritol
- EDTA
ethylenediaminetetra-acetic acid
- OASSase
O-acetyl-L-serine sulfhydrylase
- PAPS
adenosine 3-phosphate 5-phosphosulfate
- POPOP
1,4 Di 2-(5-phenyloxazolyl)-benzene
- PPO
2,5-diphenyloxazol
- RubP
ribulose-bisphosphate
- RubPCase
ribulosebiphosphate carboxylase
This is no. 8 in the series Regulation of Sulfate Assimilation in Plants. The term cysteine is used when it is clear that cystine is not involved; cyst(e)ine is used for an undefined mixture of cysteine and cystine. The concentrations are expressed in all cases relative to cysteine 相似文献