共查询到20条相似文献,搜索用时 31 毫秒
1.
Takenori Miyamoto Diego Restrepo Edward J. Cragoe Jr. John H. Teeter 《The Journal of membrane biology》1992,127(3):173-183
Summary Olfactory receptor neurons enzymatically dissociated from channel catfish olfactory epithelium were depolarized transiently following dialysis of IP3 or cAMP (added to the patch pipette) into the cytoplasm. Voltage and current responses to IP3 were blocked by ruthenium red, a blocker of an IP3-gated Ca2+-release channel in sarcoplasmic reticulum. In contrast, the responses to cAMP were not blocked by extracellularly applied ruthenium red, nor by l-cis-diltiazem or amiloride and two of its derivatives. The current elicited by cytoplasmic IP3 in neurons under voltage clamp displayed a voltage dependence different from that of the cAMP response which showed marked outward rectification. A sustained depolarization was caused by increased cytoplasmic IP3 or cAMP when the buffering capacity for Ca2+ of the pipette solution was increased, when extracellular Ca2+ was removed or after addition of 20–200 nm charibdotoxin to the bathing solution, indicating that the repolarization was caused by an increase in [Ca
i
] that opened Ca2+-activated K+ channels. The results suggest that different conductances modulated by either IP3 or cAMP are involved in mediating olfactory transduction in catfish olfactory receptor neurons and that Ca2+-activated K+ channels contribute to the termination of the IP3 and cAMP responses.Abbreviations ATP
adenosine 5-triphosphate
- BAPTA
(bis-(o-aminophenoxy)-ethane-N-N-N-N)-tetraacetic acid
- cAMP
adenosine cyclic 3,5-monophosphate
- cGMP
guanosine cyclic 3,5-monophosphate
- CTX
charybdotoxin
- DCB
3,4-dichlorobenzamil
- EDTA
ethylenediaminetetraacetic acid
- EGTA
ethylenglycol-bis-(b-aminoethyl)-N-N-N-N-tetraacetic acid
- HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- IP3
inositol-1,4,5-triphosphate
- NMDG
N-methyl-d-glucamine
We would like to thank the Tanabe Seiyaku Co., Ltd., for their gift of l-cis-diltiazem. This work was supported by National Institutes of Health grants DC00566 and BRSG S07RR05825. 相似文献
2.
Addition of ammonium to N2 fixing cultures of Azotobacter vinelandii, Klebsiella pneumoniae and Clostridium pasteurianum rapidly reduced the intracellular levels of guanosine 5-diphosphate 3-diphosphate (ppGpp) by 70–90%. This change might reflect a regulatory role of ppGpp in nitrogen metabolism.Abbreviations ppGpp
guanosine 5-diphosphate 3-diphosphate 相似文献
3.
A 40 S multienzyme complex containing mtDNA polymerase was isolated from mitochondria ofS. cerevisiae by density gradient centrifugation and by gel filtration chromatography. Besides DNA polymerase, RNA polymerase, primase, 35 exonuclease and an ATPase activities were found to be associated with it. The presence of some of these enzymes were confirmed by Western blot. This high molecular weight multienzyme complex containing DNA has most of the attributes of a putative replisome.Abbreviations BCIP
5 bromo 4 chloro 3 indolyl phosphate
- mtDNA
mitochondrial DNA
- NBT
Nitroblue tetrazolium
- PBS
phosphate buffered saline 相似文献
4.
G. Mattson E. Conklin S. Desai G. Nielander M. D. Savage S. Morgensen 《Molecular biology reports》1993,17(3):167-183
The various aspects of chemical crosslinking are addressed. Crosslinker reactivity, specificity, spacer arm length and solubility characteristics are detailed. Considerations for choosing one of these crosslinkers for a particular application are given as well as reaction conditions and practical tips for use of each category of crosslinkers.Abbreviations ABH
azidobenzoyl hydrazide
- ANB- NOS
N-5-azido-2-nitrobenzoyloxysuccinimide
- ASIB
1-(p-azidosalicylamido)-4-(iodoacetamido)butane
- ASBA
4-(p-azidosalicylamido)butylamine
- APDP
N-[4-(p-azidosalicylamido) butyl]-3(2-pyridyldithio)propionamide
- APG
p-azidophenyl glyoxal monohydrate
- BASED
bis-[-(4-azidosalicylamido)ethyl] disulfide
- BMH
bismaleimidohexane
- BS3
bis(sulfosuccinimidyl) suberate
- BSOCOES
bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone
- DCC
N,N-dicyclohexylcarbodiimide
- DFDNB
1,5-difluoro-2,4-dinitrobenzene
- DMA
dimethyl adipimidate·2HCl
- DMP
dimethyl pimelimidate·2HCl
- DMS
dimethyl suberimidate·2HCl
- DPDPB
1,4-di-(3,2-pyridyldithio)propionamido butane
- DMF
dimethylformamide
- DMSO
dimethylsulfoxide
- DSG
disuccinimidyl glutarate
- DSP
dithiobis(succinimidylpropionate)
- DSS
disuccinimidyl suberate
- DST
disuccinimidyl tartarate
- DTSSP
3,3-dithiobis (sulfosuccinimidylpropionate)
- DTBP
dimethyl 3,3-dithiobispropionimidate·2HCl
- EDC or EDAC
1-ethyl-3-(3-dimethylaminopropyl)carbodimide hydrochloride
- EDTA
ethylenediaminetetraacetic acid disodium salt, dihydrate
- EGS
ethylene glycolbis(succinimidylsuccinate)
- GMBS
N--maleimidobutyryloxysuccinimide ester
- HSAB
N-hydroxysuccinimidyl-4-azidobenzoate
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- MBS
m-maleimidobenzoyl-N-hydroxysuccinimide ester
- MES
4-morpholineethanesulfonic acid
- NHS
N-hydroxysuccinimide
- NHS-ASA
N-hydroxysuccinimidyl-4-azidosalicylic acid
- PMFS
phenylmethylsulfonyl fluoride
- PNP-DTP
p-nitrophenyl-2-diazo-3,3,3-trifluoropropionate
- SAED
sulfosuccinimidyl 2-(7-azido-4-methylcoumarin-3-acetamide) ethyl-1,3-dithiopropionate
- SADP
N-succinimdyl (4-azidophenyl)1,3-dithiopropionate
- SAND
sulfosuccinimidyl 2-(m-azido-o-nitrobenzamido)-ethyl-1,3-dithiopropionate
- SANPAH
N-succinimidyl-6(4-azido-2-nitrophenyl-amino)hexanoate
- SASD
sulfosuccinimidyl 2-(p-azidosalicylamido)ethyl-1,3-dithiopropionate
- SATA
N-succinimidyl-S-acetylthioacetate
- SDBP
N-hydroxysuccinimidyl-2,3-dibromopropionate
- SIAB
N-succinimidyl(4-iodoacetyl)aminobenzoate
- SMCC
succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate
- SMPB
succinimidyl 4-(p-maleimidophenyl) butyrate
- SMPT
4-succinimidyloxycarbonyl--methyl--(2-pyridyldithio)-toluene
- sulfo-BSOCOES
bis[2-sulfosuccinimidooxycarbonyloxy) ethyl]sulfone
- sulfo-DST
disulfosuccinimidyl tartarate
- sulfo-EGS
ethylene glycolbis(sulfosuccinimidylsuccinate)
- sulfo-GMBS
N--maleimidobutyryloxysulfosuccinimide ester
- sulfo-MBS
m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester
- sulfo-SADP
sulfosuccinimidyl(4-azidophenyldithio)propionate
- sulfo-SAMCA
sulfosuccinimidyl 7-azido-4-methylcoumarin-3-acetate
- sulfo-SANPAH
sulfosuccinimidyl 6-(4-azido-2-nitrophenylamino)hexanoate
- sulfo-SIAB
sulfosuccinimidyl(4-iodoacetyl)aminobenzoate
- sulfo-SMPB
sulfo-succinimidyl 4-(p-maleimidophenyl)butyrate
- sulfo-SMCC
sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate
- SPDP
N-succinimidyl 3-(2-pyridyldithio)propionate 相似文献
5.
T. Bagarinao R. D. Vetter 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(5):519-527
Summary Earlier whole-animal experiments have shown that the California killifish (Fundulus parvipinnis) from tidal marshes is highly tolerant to sulfide while the speckled sanddab (Citharichtys stigmaeus) from the open coast is intolerant to sulfide. In the present paper, we demonstrate that the liver mitochondria of the California killifish detoxify sulfide by oxidizing it to thiosulfate and produce ATP in the process. Sulfide oxidation is obligately and stoichiometrically linked to mitochondrial electron transport to oxygen. Concentrations up to 20 M sulfide stimulate mitochondrial respiration while 50 M sulfide causes half-inhibition. Sulfide oxidation by mitochondria is adversely affected at pH<7.4. ATP production is maximal at 10 M sulfide. The finding of sulfide oxidation coupled to ATP production by killifish mitochondria is unprecedented among vertebrates. In comparison, mitochondria of the specked sanddab oxidize sulfide at a much lower rate. This is the first demonstration of biochemical adaptation to sulfide among coastal marine fishes.Abbreviations
ADP
adenosine diphosphate
-
APHA
American Public Health Association
-
ATP
adenosine triphosphate
-
BSA
bovine serum albumin
-
EGTA
ethyleneglycol-bis-(-aminoethyl-ether) N,N,N,N-tetraacetic acid
-
G-6-PDH
glucose-6-phosphate dehydrogenase
-
HEPES
N-2-hydroxyethylpiperazine-N-2-ethane-sulfonic acid
-
HPLC
high-performance liquid chromatography; mBBr monobromobimane
-
NADP
nicotinamide adenine dinucleotide phosphate, oxidized form
- NADPH
reduced form
-
RCR
respiratory control ratio 相似文献
6.
Summary We have studied a number of condensation reactions involving ImpU, ImpT, ImpC, ImpA, ImpG, ImpUpG and ImpCpA as activated nucleotide donors and a variety of homo- and hetero-polynucleotides as templates. We did not obtain any evidence of a template effect with ImpU and ImpT, but observed some condensation of ImpC with GpG on appropriate templates. ImpA and ImpG take part in a number of more or less efficient template-directed reactions, as do ImpUpG and ImpCpA.Our results suggest that, on the primitive Earth, pyrimidine nucleotides could most easily have been incorporated into polymers as constituents of short oligomers, which contained one or more purine nucleotide. The linkage of the product depends strongly on the nature of the substrates; the percentage of the natural 3-5-linkage was, in some cases, less than 10% and, in others, as high as 70%. Wobble-pairing was often very effective in promoting condensations, suggesting that transition mutations would have been very frequent in prebiotic polynucleotide replication.Abbreviations and Conventions U
uridine
- T
thymidine
- C
cytidine
- A
adenosine
- G
guanosine
- pN
nucleoside-5-phosphate
- Np
a mixture of 2- and 3-phosphates of a nucleoside
- pNp
a mixture of the 2-5-diphosphate and 3-5-diphosphate of a nucleoside
- N1
2 pN2
a 2-5-linked dinucleoside monophosphate
- N1
3 pN2
a 3-5-linked dinucleoside monophosphate
- N5 ppN
a pyrophosphate derived from a nucleoside-5-phosphate. ImpN and ImpN1pN2 are 5-phosphorimidazolides of nucleosides and 3-5-linked dinucleoside monophosphates, respectively
- poly(N)
a homopolynucleotide
- poly (U1 C2 A4 G3)
a random copolymer derived from a substrate mixture containing U, C, A, G in ratio 1:2:4:3
- ODU
optical density units measured at 260 nm 相似文献
7.
Atsushi Hoshino Yoshishige Inagaki Shigeru Iida 《Molecular & general genetics : MGG》1995,247(1):114-117
The 6.4 kb transposable element Tpn1 belonging to the En/Spm family was found within one of the DFR (dihydroflavonol-4-reductase) genes for anthocyanin biosynthesis in a line of Japanese morning glory (Pharbitis nil) bearing variegated flowers. Sequencing of the Tpn1 element revealed that it is 6412 by long and carries 28-bp perfect terminal inverted repeats. Its subterminal repetitive regions, believed to be the cis-acting sequences for transposition, show striking structural features. Twenty-two copies of the 10-bp sequence motif GACAACGGTT can be found as direct or inverted repeats within 650 by of the 5 end of the element, and 33 copies of the sequence motif lie within 800 by of the 3 terminus. All these 22 copies of the sequence motif near the 5 terminus and 30 copies in the 3 terminal region are arranged as inverted repeats and 3–8 by AT-rich sequences are detected between these inverted repeats. In addition, four copies of 122-bp tandem repeats and six copies of 104-bp tandem repeats are present in the 5 and 3 subterminal repetitive regions, respectively. No large open reading frame characteristic of autonomous elements of the En/Spm family can be detected within the element. The results are discussed with respect to heritable changes in flower variegation in this line of Japanese morning glory. 相似文献
8.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
9.
We describe here the nucleotide sequence of an anther-specific gene (sf18) from sunflower, encoding a proline- and glycine-rich polypeptide with a hydrophobic amino-terminus (signal peptide). The gene is split by a 211 by intron and is partially related to another anther-specific gene (sf2) from sunflower with which it shares important sequence stretches in the 5 coding and upstream regions. We propose that the two genes have originated via exon shuffling, during which a copy of a DNA segment including the promoter region as well as a signal peptide coding sequence has been transferred into the upstream region of two different potential coding sequences, generating two novel genes which display the same specificity of expression and which both encode an extracellular protein. While the 5 region of the intron is highly conserved as part of the transferred region and may play a role in the selection of the 5 splice site, a common octanucleotide at the 3 end of the intron of the two genes might be involved in 3 splice site selection. 相似文献
10.
Partial purification of myosin from lily pollen tubes by monitoring with in vitro motility assay 总被引:1,自引:0,他引:1
Summary Myosin in pollen tubes ofLilium longiflorum was partially purified, using an in vitro motility assay as a monitor. The main components in the partially purified preparation had molecular masses of 110, 120, and 140 kDa in SDS-PAGE. They became bound to actin filaments in an ATP-dependent manner. Among the components, only that of 120 kDa became bound to ATP and was concluded to be the heavy chain of pollen tube myosin.Abbreviations ATP
adenosine-5-triphosphate
- DTT
dithiothreitol
- EB
extraction buffer
- EGTA
ethyleneglycol-bis-(-aminoethylether) N, N, N, N-tetraacetic acid
- PAGE
polyacrylamide gel electrophoresis
- PIPES
piperazine-N,N-bis-(2-ethanesulfonic acid)
- PMSF
phenylmethylsulfonyl fluoride
- SDS
sodium dodecylsulfate
- TBS
Tris buffered saline
- TEB
Tris-EGTA buffer 相似文献
11.
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
12.
S. H. Ogo C. F. Bernardes M. L. Glass M. A. Torsoni A. E. Vercesi 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(7):614-619
Digitonin was applied to permeabilize the plasma membrane of Bothrops alternatus erythrocytes to study respiration, oxidative phosphorylation and Ca2+ transport by mitochondria in situ. These mitochondria oxidized added NAD-linked substrates, succinate and N,N,N, N-tetramethyl-p-phenylenediamine. Respiration was sensitive to rotenone and cyanide but not to antimycin A. This indicates that Bothrops mitochondria possess the respiratory complexes NADH-ubiquinone, succinate-ubiquinone, and ferrocytochrome c-oxygen oxidoreductases, although the lack of sensitivity to antimycin A raises doubt about the composition of the ubiquinol cytochrome c-reductase complex. An ability to build up and sustain a membrane potential was documented by their capacity to accumulate tetraphenylphosphonium and Ca2+ through an uncoupler-sensitive mechanism. Addition of ADP caused a transient decrease in the membrane potential, indicating that this is the predominant driving force for ATP synthesis as in most types of mitochondria. Uncoupling of phosphorylation from the oxidative process increased hemoglobin O2 affinity, which suggests that ATP production by mitochondria may participate in modulation of O2 transport by hemoglobin.Abbreviations
membrane potential
- BAE
Bothrops alternatus erythrocytes
- DNP
2,4-dinitrophenol
- DPG
2,3-diphosphoglycerate
- EGTA
ethyleneglycol tetra-acetic acid
- FCCP
carbonylcyanide p-trifloromethoxyphenylhydrazone
- TMPD
N,N,N,N-tetramethyl-p-phenylenediamine
- TPP+
tetraphenylphosphonium
- TRIS
tris-(hydroxymethyl)aminomethane 相似文献
13.
The rate of CO2- and p-benzoquione-dependent photosynthetic O2 evolution by Anabaena variabilis cells remained unaltered and the rate of O2 uptake observed after switching off the light (endogenous respiration) was enhanced by a factor of 6–8 when the O2 concentration was increased from 200 to 400 M. Photosystem-I-linked O2 uptake and respiration of the cells incubated with ascorbate and N,N,NN-tetramethyl-p-phenylenediamine was not appreciable influenced by the O2 concentration. 2-Iodo-6-isopropyl-3-methyl-2,4,4-trinitrodiphenyl ether, blocking electron transfer at the plastoquinone level, suppressed O2 evolution and had no influence on endogenous respiration. 2-n-Heptyl-4-hydroxyquinoline-N-oxide, an inhibitor of electron transfer between photosystems II and I, as well as the cytochrome-oxidase inhibitors N
3
-
, CN- and NH2OH, caused a 35–50% retardation of endogenous respiration and blocked photosynthetic O2 evolution. The molar ratio of cytochromes b6, f, c-553, aa3 and photosystem-I reaction centers in the isolated membranes equalled approx. 2:1:2:0.7:2. It is inferred that endogenous respiration of A. variabilis cells is inhibited by the light-induced electron flow through both photosystems at the level of the plastoquinone-plastocyanin-oxidoreductase complex.Abbreviations DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- DNP-INT
2-iodo-6-isopropyl-3-methyl-2,4,4-trinitrodiphenyl ether
- Hepes
4-(2-hydroxyethyl)-1-piperazine ethansulfonic acid
- TMPD
N,N,NN-tetramethyl-p-phenylenediamine 相似文献
14.
Hans Kleinig Hans Reichenbach Hans Achenbach Jochen Stadler 《Archives of microbiology》1971,78(3):224-233
Summary The carotenoid pigments of the myxobacterium Sorangium compositum were analyzed by chromatographical and chemical techniques and by visible, infra red, and mass spectroscopy. Besides -carotene, neurosporene, torulene, lycopene, and 1,2-dihydro-1-hydroxy--carotene, four new carotenoid glycosides were found. These pigments were identified as 1,2-dihydro-1-hydroxy-torulene glucoside ester (I), 1,2-dihydro-3,1-dihydroxy-torulene glucoside ester (III), 1,2-dihydro-1-hydroxy-torulene rhamnoside (II), and 1,2-dihydro-3,1-dihydroxytorulene rhamnoside (IV).Fifth communication on the carotenoids of myxobacteria. Fourth communication see Arch. Mikrobiol. 76, 364–380 (1971). 相似文献
15.
Summary. Epifluorescence microscopy of mature pollen grains of Turnera ulmifolia and Zantedeschia aethiopica stained with 4,6-diamidino-2-phenylindole demonstrated the presence of fluorescent cytoplasmic DNA aggregates in the male reproductive cells of both species. Double staining of the cells with 4,6-diamidino-2-phenylindole and 3,3-dihexyloxacarbocyanine iodide in Technovit resin sections showed that the mitochondria of these cells did not correspond to the fluorescent cytoplasmic DNA aggregates. Electron microscopy studies revealed both plastids and mitochondria in the cells of these species. In addition, immunoelectron microscopy using an anti-DNA monoclonal antibody showed clear labeling of plastids but not mitochondria. These data provide cytological evidence for biparental plastid inheritance and maternal mitochondrial inheritance in these species.Correspondence and reprints: College of Life Sciences, Peking University, Beijing 100871, Peoples Republic of China. 相似文献
16.
Summary The active sites of actin of oneCharaceae species were found to interact with the endoplasmic factor from a different species. Protoplasm was suqueezed out of cells ofChara australis with vacuoles that had been perfused beforehand with a medium containing EGTA and Mg · ATP. Centrifugation of this protoplasmic mixture divided it into the supernatant composed of endoplasmic granules and the precipitate composed of chloroplasts and nuclei. When the endoplasmic granular aggregates were introduced into a tonoplast-freeNitella axilliformis cell treated with NEM to inactivate the endoplasmic factor, they became attached to theNitella gel and streamed longitudinally with the polarity. Treatment of the endoplasmic granules with the strong Mg2+chelator CyDTA (1,2-cyclohexane diamineN, N-tetraacetic acid) irreversibly inhibited reconstitution of the cytoplasmic streaming.Abbreviations APW
artificial pond water
- ATP
adenosine-5-triphosphoric acid
- CyDTA
cyclohexanediamine-N,N-tetraacetic acid
- DTT
dithiothreitol
- EGTA
ethyleneglycol-bis-(-aminoethylether)-N,N-tetraacetic acid
- HMM
heavy meromyosin
- NEM
N-ethylmaleimide
- PEP
phosphoenolypyruvate
- PIPES
piperazine-N,N-bis-(2-ethane-sulfonic acid)
- PK
pyruvate kinase
- PMSF
phenylmethylsulfonylfluoride 相似文献
17.
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
18.
Membrane preparations, capable of high rates of respiration-linked ATP synthesis, have been obtained from a gram-positive methylotrophic bacterium Bacillus sp. MGA3. NADH, succinate, reduced TMPD and methanol were shown to be suitable substrates for the oxidative phosphorylation. Esterification of orthophosphate was dependent on electron transfer, as evidenced by the requirement for both substrate and oxygen. Phosphorylation was also dependent on ADP and was destroyed by boiling the membrane preparation. The phosphorylation was markedly uncoupled by carbonyl cyanide p-(trichloromethoxy)-phenylhydrazone (CCCP) and was inhibited by N,N-dicyclohexylcarbodiimide (DCCD). KCN caused strong inhibition of substrate oxidation as well as phosphorylation for all substrates tested. Rotenone, amytal and antimycin A caused inhibition when NADH or methanol were used as substrates. Antimycin A inhibited respiration and ATP synthesis with succinate as substrate and had no effect on ascorbate —N,N,N,N-tetramethyl-p-phenylenediimide (TMPD) oxidation by membrane preparations of Bacillus sp. MGA3. P/O ratios determined were 2.4 with NADH, 1.7 with succinate and 0.8 with reduced TMPD. The measured P/O ratio with methanol-oxidizing system was similar to that with NADH (about 2.4).Abbreviations CCCP
Carbonyl cyanide p-(trichloromethoxy)-phenylhydrazone
- DCCD
N,N-dicyclohexylcarbodiimide
- TMPD
N,N,N,N-tetramethyl-p-phenylenediimide
- Q
ubiquinone Q 相似文献
19.
W. O. Abel W. Knebel H. -U. Koop J. R. Marienfeld H. Quader R. Reski E. Schnepf B. Spörlein 《Protoplasma》1989,152(1):1-13
Summary An X-ray induced mutant (PC22) of the moss,Physcomitrella patens was analysed with respect to its morphology, physiology and suitability for microculture techniques. The mutant protonemata are defective in bud formation and in chloroplast division. As a consequence of the latter, giant chloroplasts are formed which disturb the development of the phragmoplast, the formation of regular cross walls, and cell division. Abnormal cross walls are rich in callose. The actin cytoskeleton was found to be less regularly developed in the mutant than in the wild type. Three-dimensional analysis of the microtubular arrangement with confocal laser scan microscopy demonstrates a close association between spindle- or phragmoplast- and interphase-microtubules. The deficiencies in chloroplast division and in bud formation can partly be compensated for by exogeneously applied cytokinin. The suitability of this particular developmental mutant for further studies was shown by regeneration of protoplasts in microculture and microinjection of the fluorochrome Lucifer yellow into the chloroplast.Abbreviations CLSM
confocal laser scan microscope
- DAPI
diamidinophenyl indole
- DiOC
3,3-dihexyloxacarbocyanine iodide
- EGTA
ethylene glycol-bis-(-amino-ethylether-N,N,N,N-tetraacetic acid
- i6Ade
N6-(2-isopentenyladenine)
- PIPES
piperazine-N, N-bis-2-ethanesulfonic acid
- ptDNA
chloroplast DNA
Devoted to the memory of Prof. Dr. O. Kiermayer, our colleague and friend. 相似文献
20.
Servé W. M. Kengen Judith J. Mosterd Rob L. H. Nelissen Jan T. Keltjens Chris van der Drift Godfried D. Vogels 《Archives of microbiology》1988,150(4):405-412
The enzymatic conversion of formaldehyde to CH3S-CoM in crude extracts of Methanobacterium thermoautotrophicum was used as a means to investigate the methyl-tetrahydromethanopterin: HS-CoM methyltransferase reaction. All components necessary for formaldehyde conversion were shown to be present in a soluble protein fraction. This soluble cell fraction still contained a major amount of corrinoids. Apart from tetrahydromethanopterin no other soluble cofactors were required for formaldehyde conversion. The dependence of the system on catalytic amounts of ATP was shown to be specific. Several nucleoside triphosphates or ADP were unable to substitute for ATP. Remarkably, various strong reducing systems, especially titanium(III)citrate could replace ATP to a large extent. The ATP-dependent formaldehyde conversion to CH3S-CoM was inhibited in the presence of nitrous oxide, detergents or 2,3-dialdehyde-ATP. The results support a role for a corrinoid protein in the methyl-tetrahydromethanopterin: HS-CoM methyltransferase reaction at which ATP is involved in the activation of this protein, probably in the conversion of inactive B12a or B12r to active B12s.Abbreviations HS-CoM
Coenzyme M, 2-mercaptoethanesulfonate
- CH3S-CoM
methylcoenzyme M, 2-(methylthio)ethanesulfonate
- H4MPT
5,6,7,8-tetrahydromethanopterin
- BES
2-bromoethanesulfonate
- BCE
boiled cell-free extract
- DTT
dithiothreitol
- TCS
3,3,4,5-tetrachlorosalicylanilide
- DNTB
2,2-dinitro-5,5-dithiobenzoic acid
- TES
N-tris(hydroxymethyl)methyl-2-aminoethanesulfonate
- HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- PIPES
piperazine-N,N-bis[2-ethanesulfonic acid]
- AMP-PNP
5-adenylyl imidophosphate 相似文献