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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.
Morishita F Shimada A Fujimoto M Katayama H Yamada K 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(7):533-540
The signal-transduction system that mediates the melanosome-aggregating response in melanophores of the black-moor goldfish, Carassius auratus, was investigated by examining the inhibition of adenylate cyclase activity mediated by -adrenoceptors in cultured cells. When the melanophores were incubated with 1 mmol·l-1 3-isobutyl-1-methylxanthine for 5 min, the intracellular level of cyclic adenosine-3,5-monophosphate increased two- to three-fold. Norepinephrine at 100 nmol·l-1 and naphazoline at 1 mol·l-1 inhibited the 3-isobutyl-1-methylxanthine-induced accumulation of cyclic adenosine-3,5-monophosphate in the cells in both the presence and the absence of isoproterenol, a -adrenergic agonist. Methoxamine and phenylephrine also reduced the extent of accumulation of cyclic adenosine-3,5-monophosphate, but only when they were present at relatively high concentrations (above 100 mol·l-1). The range of concentrations at which norepinephrine inhibited the accumulation of cyclic adenosine-3,5-monophosphate was consistent with the range at which it induced the aggregation of melanosomes. Pretreatment of the cells with pertussis toxin (1 g·ml-1) for 15 h or treatment with 100 nmol·l-1 yohimbine (an 2-adrenergic antagonist) inhibited the effects of the -adrenergic agonists on both the aggregation of melanosomes and the 3-isobutyl-1-methylxanthine-induced accumulation of cyclic adenosine-3,5-monophosphate, but prazosin (an 1adrenergic antagonist) at 100 nmol·l-1 was not inhibitory. These results indicate that the melanosome-aggregating response of the goldfish melanophore is induced mainly via inhibition of the activity of adenylate cyclase, which occurs as result of stimulation of a pathway that involves 1adrenergic and a inhibitory GTP-binding protein.Abbreviations A-kinase
cAMP-dependent protein kinase
- BSS
balanced salts solution
- CaM
calmodulin
- cAMP
cyclic adenosine-3,5-monophosphate
- Clo
clonidine
- EDTA
ethylenediaminetetra-acetic acid
- G-protein
GTP-binding protein
- HEPES
N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid
- IBMX
3-isobutyl-1-methylxanthine
- IP3
inositol 1,4,5-trisphosphate Mex, methoxamine
- MSH
melanocyte-stimulating hormone
- Nap
naphazoline
- NE
norepinephrine
- Oxy
oxymetazoline
- Phe
phenylephrine
- PTX
pertussis toxin 相似文献
3.
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
4.
The filamentous cyanophyteNostoc muscorum A grew aseriately in light in a mineral salts (sugar-free) culture medium supplemented with adenosine 3:5-cyclic-monophosphate or N6, O2-dibutyryl adenosine 3:5-cyclic-monophosphate (1 mM). The aseriate morphology thus formed in the light on the 10th day following inoculation was similar to that formed in the dark after 20–30 days growth in cAMP-free medium containing glucose or sucrose. Inoculum previously grown in sucrose- or glucose-containing medium displayed aseriate morphology with lesser proliferation of coccoid cells as compared to inoculum grown in the absence of glucose or sucrose. cGMP, ADP, AMP and inhibitors of phosphodiesterase (theophylline and caffeine) did not have any effect on the persistence of aseriate morphology. However they stimulated cell division at the aseriate stage and delayed the release of hormogonia.Abbreviations cAMP
adenosine 3:5-cyclic-monophosphate
- db cAMP
N6, O2-dibutyryl adenosine 3:5-cyclic-monophosphate
- cGMP
guanosine 3:5-cyclic-monophosphate
- ATP
adenosine 5-triphosphate
- ADP
adenosine5-diphosphate
- AMP
adenosine 5-monophosphate 相似文献
5.
Direct evidence has been obtained for the presence of adenosine-3:5-cyclic monophosphate (cAMP) in tobacco (Nicotiana tabacum L.) callus tissue cultures, bean (Phaseolus vulgaris L.) seedlings and immature kernels of sweet corn (Zea mays L.) through the use of a highly specific and sensitive gas chromatography-mass spectrometric assay. Levels of endogenous cAMP ranged from 70 to 126 pmol/g fresh weight. Corresponding levels of cAMP determined for the same samples using radioimmunoassay were consistently three to four times higher. Contrary to previous reports for citrus plants, measurable levels of cAMP could not be detected in young lemon leaves within the limits of detection of the mass-spectrometric assay method. In the case of tobacco callus tissue, the coumarin glucoside, scopolin, which was present in large amounts and showed similar chromatographic behaviour to cAMP, interferred strongly with the mass-spectrometric measurements of cAMP in inadequately purified extracts. The use of high-performance liquid chromatography, in addition to standard chromatographic purification methods, produced highly purified plant extracts for quantitation of cAMP and also provided a method for the separation of cAMP from its 2:3-isomer.Abbreviations cAMP
adenosine-3:5-cyclic monophosphate
- 2:3-cAMP
adenosine-2:3-cyclic monophosphate
- GC-MS-MID
combined gas chromatography-mass spectrometry with selected multiple-ion-detection
- HPLC
high-performance liquid chromatography
- RIA
radioimmunoassay
- TLC
thin-layer chromatography 相似文献
6.
S. Sakuanrungsirikul C. H. Hocart J. D. I. Harper C. W. Parker P. C. L. John 《Protoplasma》1996,192(3-4):159-167
Summary Three independent isolates ofChlamydomonas, selected for caffeine resistance, were found to arrest in G1 phase, as determined by quantitative fluorescence measurements of DNA, when grown at a non-permissive temperature. This cell cycle arrest correlated with lowered levels of cAMP and of adenylate cyclase activity. The arrested cells could be rescued by added cAMP but not AMP, hence the defect was not one of general purine metabolism. Back-crosses to wild type revealed that the phenotypes observed result from a combination of three separable mutations. It is clear that the mutations define functions that are more stringently required for cell division than for growth since the mutant strains are able to grow up to fifteen times normal size while blocked at the non-permissive temperature. The possible interaction of cAMP dependent events with division is discussed.Abbreviations AMP
adenosine 5-monophosphate
- ATP
adenosine 5-triphosphate
- BSA
bovine serum albumin
- cAMP
adenosine 3,5-cyclicmonophosphate
- db-cAMP
dibutyryl-cAMP
- DNA
deoxyribonucleic acid
- DTT
dithiothreitol
- -cAMP
1,N6-etheno-cAMP
- EDTA
ethylenediaminetetraacetic acid
- EGTA
ethylene glycol-bis(-aminoethylether)-N,N,N,N-tetraacetic acid
- HPLC
high performance liquid chromatography
- LSA
low sulphur-high salt-acetate medium
- LYP LSA
media containing yeast extract and proteose peptone
- M1, 2, 3
mutants 1, 2, 3
- PDE
phosphodiesterase
- TAP
trisacetate-phosphate medium
- TLC
thin layer chromatography
- TYP TAP
medium containing yeast extract and proteose peptone 相似文献
7.
Four radiolabled congeners of biphenyls with increasing chlorine content (biphenyl; 1-monochlorobiphenyl; 2,2,4,4-tetrachlorobiphenyl; and 2,2,4,4,5,5-hexachlorobiphenyl) were provided to suspension cultures of rose (Rosa sp. cv. Paul's Scarlet) for 4 days. Both the kinetics of 14C exchange between the cells and medium, and the metabolism of the parent compounds depended on the chlorine content of the congeners. Analysis of both the cells and their medium showed that of the recovered radioactivity 88%, 86%, and 3% of the biphenyl, 1-PCB, and 2,2,4,4-PCB were metabolized respectively to polar and insoluble residue products. The 2,2,4,4,5,5-PCB did not appear to be metabolized. 相似文献
8.
Irene M.A. Nooren Ke-Yu Wang Philip N. Borer István Pelczer 《Journal of biomolecular NMR》1998,11(3):319-328
The subject RNA models the binding site for the coat protein of the R17 virus, as well as the ribosome recognition sequence for the R17 replicase gene. With an RNA of this size, overlaps among the sugar protons complicate assignments of the 1H NMR spectrum. The cross peaks that overlap significantly in 2D-NOE spectra can frequently be resolved by introducing a third, in our approach the double-quantum, frequency axis. In particular the planes in a 3D-NOE/2QC spectrum perpendicular to the 2Q axis are extremely useful, showing a highly informative repeating NOE-2Q pattern. In this experiment substantial J-coupling confers special advantages. This always occurs for geminal pairs (H5/H5 for RNA plus H2/H2 for DNA), as well as for H5/H6, for H3/H4 in sugars with substantial populations of the N-pucker, for H1/H2 for S-puckered sugars, and usually for H2/H3. For the 24-mer RNA hairpin the additional information from the 3D-NOE/2QC spectrum allowed assignment of all of the non-exchangeable protons, eliminating the need for stable-isotope labeling. 相似文献
9.
W. Giard P. Favrel E. Boucaud-Camou 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,164(7):518-523
The (neuro)endocrine control of enzyme release from invertebrate digestive cells remains poorly understood. A tissue dissociation procedure was developed to investigate the regulatory mechanisms of -amylase discharge from the cells of the stomach-digestive gland complex of the scallop Pecten maximus. The validity of the experimental system was tested by increasing the intracellular concentration of second messenger analogues (N
6,2-o-dibutyryl-adenosine-3,5 cyclic monophosphate and the ionophore A23187) known to mimic the activity of naturally occurring secretagogues in vertebrates: N
6,2-o-dibutyryl-adenosine-3,5 cyclic monophosphate increased the time and dose-dependent release of -amylase in a similar way as in vertebrates. A23187 was also very effective in inducing enzyme discharge. Since the in vitro bioassay was shown to be functional and because axon terminals were previously seen in close contact to -amylase secreting cells, the effect of some classic neurotransmitters was explored. Only the cholinergic agonist carbachol and dopamine evoked a secretory response. Maximal stimulation of -amylase release was reached at 10-5 mol·l-1 carbachol; at the same concentration dopamine was less effective than carbachol. By contrast, serotonin was totally inactive. The in vitro bioassay should prove useful for the identification of regulatory molecules involved in the control of enzyme discharge and to study stimulus secretion coupling mechanisms in scallop digestive cells.Abbreviations DBcAMP
N
6, 2-O-dibutyryl-adenosine-3,5 cyclic monophosphate
- cAMP
adenosine-3,5 cyclic monophosphate 相似文献
10.
Physiological conditions necessary for the formation of plastocyanin and the concurrent cessation of cytochrome c-553 formation were studied in cells of copper-deficient Scenedesmus acutus after the addition of copper. Plastocyanin is formed after a lag-phase, leaving constant the content of plastidic cytochrome c-553. Therefore, the concentration of plastocyanin per cell increases and the concentration of cytochrome c-553 decreases during growth. Formation of plastocyanin during the induction period studied is dependent on light intensity. In the dark, there is a 90% inhibition, whereas under light intensities above 50 Wm-2, a ratio of 1.3 molecules plastocyanin per 1,000 molecules chlorophyll is attained.Plastocyanin formations is inhibited by the uncoupler carbonylcyanide-p-trifluoromethoxy phenylhydrazone (FCCP), but not by moderate concentrations of 3-[3,4-dichlorophenyl]-1,1-dimethylurea (DCMU), and by keeping the algae under a nitrogen atmosphere without CO2. Concurrently, the cultures treated with FCCP show a decreased endogenous ATP level. The ATP is necessary for plastocyanin formation.Abbreviations FCCP
carbonylcyanide-p-trifluoromethoxyphenylhydrazone
- DCMU
3-[3,4-dichlorophenyl]-1,1-dimethylurea
- pcv
packed cell volume 相似文献
11.
The role of purine and pyrimidine ribosides, nucleotides and substituted xanthines in the differentiation of chloronema filaments in suspension cultures of protonema of the moss Funaria hygrometrica Hedw. has been examined. Cyclic adenosine-3,5-monophosphate (cAMP) and mono-and dibutyryl cAMP evoked the maximum response in wild-type protonema. ADP and ATP also enhanced chloronema differentiation but were less active than cAMP; pyrimidine derivatives were completely inactive. Inhibitors of cyclic-nucleotide phosphodiesterase aminophylline, theophylline and ICI 58, 301 (3-acetamido-6-methyl-8-n-propyl-s-triazolo-(4,3a)-pyrazine)-mimicked the effect of cAMP. A leaky, chloronema-repressed mutant was isolated and in this mutant cAMP was much more active than cyclic guanosine monophosphate and ADP in enhancing chloronema differentiation. These results strongly indicate that cAMP is involved in chloronema differentiation in Funaria, and a hypothesis on growth regulation in protonema cell cultures is proposed.Abbreviations cAMP, cyclic AMP
cyclic adenosine-3, 5-monophosphate
- cCMP, cGMP, cIMP
cyclic cytosine-, guanosine-and inosine-3, 5-monophosphates, respectively
- IAA
indole-3-acetic acid
- ICI 58,301
3-acetamido-6-methyl-8-n-propyl-s-triazolo-(4,3a)-pyrazine 相似文献
12.
Hisanori Suzuki Yasuharu Tanaka Daniela Tornese Buonamassa Benedetta Farina Enzo Leone 《Molecular and cellular biochemistry》1987,74(1):17-20
The effects of analogs of diadenosine 5,5-p1,p4-tetraphosphate (Ap4A) were examined on the ADP-ribosylation reaction of histone Hl catalysed by purified bovine thymus poly(ADP-ribose)transferase. Among the compounds tested, Ap4A and ApCH2PPPA were shown to be the most efficient inhibitors of the enzyme. From kinetic studies of their action, it appears that Ap4A and ApCH2pppA might be mixed type inhibitors.Abbreviations ADP-ribose
adenosine diphosphate ribose
- ADPRT
poly-(ADP-ribose)transferase
- Ap4A
diadenosine 5,5-p1,p4-tertraphosphate
-
Ap4A
diadenosine 5,5-p1,p4(-1,N6-ethenyl-)tetra-phosphate
-
ApAA
diadenosine 5,5-p1,p4(-N6(-1,N6-)bisethenyl-)tetraphosphate
- ApCH2pppA
diadenosine 5,5-p1,p4(-p1,p2-methylene-)tetraphosphate
- AppCH2ppA
diadenosine 5,5-p1,p4(-p2,p3methylene-)tetraphosphate
- AppNHppA
diadenosine 5,5-p1,p4(-p2,p3-amino-)tetraphosphate
- AppCHBrppA
diadenosine 5,5-p1,p4(-p2,p3-bromine methyno-)tetraphosphate
- CpCH2ppCH2PC
dicytidine 5,5-p1,p4(-p1,p2-p3,p4-bismethylene-)tetraphosphate
- ApCH2ppCH2pA
diadenosine 5,5-p1,p4(-p1,p2-p3,p4-bismethylene-)tetraphosphate. 相似文献
13.
Tadako Murayama Isao Uno Kimihiko Hamamoto Tatsuo Ishikawa 《Archives of microbiology》1985,142(2):109-112
A cpk mutant of Neurospora crassa with morphological alteration was obtained spontaneously during the cross between the wild-type and a glycerol utilizing cr-l strain. The growth rate of cpk was intermediate between the wild-type and cr-1 mutant strains. The cpk conidia contained a reduced level of carotenoid pigments as compared to the wild-type conidia. The cpk mutant had no detectable amount of cyclic adenosine 3,5-monophosphate (cAMP)-binding protein at all stages of growth tested. On a DEAE-Sephacel column chromatogram, protein kinase activity of the wild type was eluted at two peaks; the first peak was cAMP-dependent, and the second one was not. In contrast, the cpk strain had two peaks of cAMP-independent enzymes. It is suggested that cAMP-dependent protein kinase may be altered in the cpk mutant into a cAMP-independent type by an alteration of the regulatory subunit of this enzyme.Abbreviations cAMP
Cyclic adenosine 3,5-monophosphate
- 8-N3-[3H] cAMP
8-azido-[3H]cyclic adenosine 3,5-monophosphate 相似文献
14.
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
15.
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
16.
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
17.
Nuclei were isolated from the shoots of Zea mays and assayed for endogenous RNA polymerase activity in vitro. Maximum incorporation from radioactive precursors (70 pmol [3H]uridine 5 monophosphate/100 g DNA) was reached after incubation for 1 h at 25°C. The RNA product, analysed by polyacrylamide gel electrophoresis, was polydisperse in size with an upper limit of 2x106 daltons. Discrete peaks of rRNA were not detected, probably because of endogenous ribonuclease activity. The inclusion of -amanitin (4 g/ml) in the incubation reduced the total incorporation by approximately 40% but did not significantly alter the size of the RNA product. Although 40% of the total activity could be attributed to RNA polymerase II, [3H]RNA synthesised in vitro was found not to contain long sequences of poly (A).Abbreviations oligo (dT)
oligo (deoxythymidylic acid)
- poly (A)
poly (adenylic acid)
- GTP
guanosine 5 triphosphate
- ATP
adenosine 5 triphosphate
- CTP
cytidine 5 triphosphate
- UTP
utidine 5 triphosphate
- UMP
uridine 5 monophosphate
- PPO
2,5-diphenyloxazole
- POPOP
1,4-di-2-(5-phenyloxazolyl) benzene 相似文献
18.
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
19.
A yeast-mycelium (Y-M) transition in Candida albicans was induced by exogenous yeast extract, adenosine, adenosine 5-monophosphate (AMP), adenosine 5-diphosphate (ADP), adenosine 35 cyclic monophosphate (cAMP) and its analogue N6, O2-dibutyryl adenosine 35-cyclic monophosphate (dbcAMP) in defined liquid medium at 25°C. Adenosine 5-triphosphate (ATP) was found to delay germ tube formation in yeast cells, whereas the cAMP phosphodiesterase inhibitors, theophylline and caffeine, induced a Y-M transition. Intracellular and extracellular cyclic AMP levels increased during the yeast-mycelium transition and maximum levels of intracellular cyclic AMP coincided with maximum germ tube formation. Of the many inducers and inhibitors of germ tube and mycelium formation in C. albicans tested, including incubation at 37°C or in the presence of 1.5mM CaCl2, the calmodulin inhibitor calmidazolium (R24571) added together with CaCl2 induced the highest intra- and extracellular cyclic AMP levels. These results confirm the involvement of cyclic AMP in the yeast-mycelium transition of C. albicans. 相似文献
20.
Fabián Atlasovich José A. Santomé Horacio N. Fernández 《Molecular and cellular biochemistry》1993,120(1):15-23
Summary Photoreactive probes for the hydrophobic pocket of the liver fatty acid-binding protein, 11-(5-azido-salicylamido)-undecanoic acid (5 ASU) and its acetyl ester (Ac5 ASU), were synthesized and their interaction with the protein was assessed. Fatty acid-binding proteins are closely related proteins which are abundantly expressed in tissues with active lipid metabolism. A simple model that assumes that the protein possesses a single kind of sites fitted the binding of radioiodinated 5 ASU to L-FABP satisfactorily. The apparent dissociation constant, 1.34×10–7 M, evidenced a slightly higher affinity than that reported for C16–C20 fatty acids. Consistent with the binding curve, 5 ASU effectively competed with palmitic acid for the hydrophobic sites and the effect was nearly complete for concentrations of 1 gmM; oleic acid, in turn, displaced the radiolabelled probe. Irradiation at 366 nm of125I-5 ASU bound to L-FABP caused the covalent cross-linking of the reagent. The amount of radioactivity covalently bound reached a maximum after 2 min thus agreeing with the photo-activation kinetics of the unlabelled compound that evidenced a t1/2 of 31.1 sec. The yield with which probes bound to L-FABP became covalently linked to the protein, appraised after SDS-PAGE of irradiated samples, was estimated as 23 and 26 per cent for 5 ASU and Ac5 ASU respectively. In turn, irradiation of L-FABP incubated with 5ASU or Ac5 ASU resulted in the irreversible loss of about one fourth its ability to bind palmitic acid. Both results, taken together, suggested that the derivatives are linked to the protein through the sites for fatty acids. When cross-linking of125I-5 ASU was performed after incubation with delipidated cytosol and products were analyzed by SDS-PAGE, a band was visualized in a position similar to that of purified L-FABP.Abbreviations FABP
Fatty Acid-Binding Protein
- L-FABP
Hepatic FABP
- I-FABP
Intestinal FABP
- C-FABP
Cardiac FABP
- 5 ASU-11
(5-azido-salicylamido)-undecanoic acid
- Ac5 ASU-11
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