共查询到20条相似文献,搜索用时 15 毫秒
1.
A Ras-related NTP-binding protein was partially purified froma membrane fraction derived from the mycelia of Neurospora crassa.[-32P]ATP and [-32P]GTP were incubated with mem brane and solublefractions which were then irradiated with UV light to inducecrosslinking of tightly bound nucleotides. After SDS-polyacrylamidegel electrophoresis, blotting onto a nitrocellulose filter andautoradiography it was apparent that most of the proteins thatbound [-32P]-GTP also bound [-32P]ATP. Pretreatment of the membranefraction with Ras-specific antibody effectively blocked thebinding of [-32P]ATP and [-32P]GTP to several ATP-GTP-bindingproteins. The band of a protein with a molecular weight of 26kDa on the SDS-polyacrylamide gel cross-reacted strongly withthe Ras-specific antibody. The protein was extracted from thegel and further purified by repeated gel electrophoresis. Thepurified protein bound [-32P]ATP, [-32P]-GTP, [-32P]CTP and[-32P]UTP at 1.6x10 M and was autophosphorylated in thepresence of [-32P]ATP and [-32P]GTP at 1.7x10 M. Pretreatmentof the protein with Ras-specific antibody partially blockedthe autophosphorylation in the presence of these nucleotides.The binding of [-32P]ATP to the NTP-binding protein was blockedby addition of ATP at 104103 M. ATP ata concentration of 104 M prevented the binding of [-32P]to a greater extent than did GTP at the same concentration.Binding of [-32P]CTP and [-32P]UTP to the protein was also observed. (Received October 7, 1991; Accepted July 14, 1992) 相似文献
2.
Enzymatic Degradation of Chlorophyll in Chenopodium album 总被引:3,自引:0,他引:3
The breakdown of chlorophyll (Chi) in crude extracts of Chenopodiumalbum (white goose foot) in the dark was examined. Derivativesof pheophorbide were formed when Chi or chlorophyllide wasincubated with depigmented crude extracts. The formation ofpheophorbide was completely prevented by heat treatment of extracts,indicating that the reaction was enzymatic, and the presenceof a Mg-releasing enzyme, the so called Mg-dechelatase, waspostulated. This hypothesis was strongly supported by the observationthat the formation of pheophorbide was inhibited by 51% by 10mM MgCl2. Analysis by high-performance thin-layer chromatography(HPTLC) and liquid chromatography (HPLC) showed that the appearanceof chlorophyllide , pheophorbide 132-hydroxychlorophyllide and pyropheophorbide was accompanied by a concomitant decreasein levels of Chi The formation of 132-hydroxychloro-phyllide was not clearly an enzymatic reaction and requires furtherexamination. It appears that Chl is degraded in a crude extractof C. album via the following enzymatically catalyzed reactions
(Received September 10, 1990; Accepted November 15, 1990) 相似文献
3.
Subunits (, ß, ) and mixtures of subunits ( ß, , ß , ß ) were isolated without denaturationfrom a chloroform extract of chloroplast coupling factor 1 (CF1)from maize (Zea mays var. Ushiku 5-4) and from spinach by fastprotein liquid chromatography (FPLC), on an anion-exchange columnof Mono-Q in the presence of n-octylglucoside (OG) and on achromatofocusing column of Mono-P. The ß -subunitcomplex (CF1 ß ) was the minimum unit required forATPase activity, as was confirmed by the reconstituted complexof ß and subunits. An subunit isolated from maizeinhibited the ATPase activity of CF1 ß from bothmaize and spinach. CF1 ß was found to contain anOG-dependent Mg2+-ATPase. The ATPase activity of CF1 ß required divalent cations, such as Mg2+ or Mn2+, for its expressionin the presence of OG; its optimum pH was 8.0 and it was markedlyinhibited by NaN3. The enzyme hydrolyzed ATP in prefernece toGTP but not CTP, UTP, ADP, AMP or pNPP. Lineweaver-Burk plotsof its activity were curvilinear in the range of 0.60.7mM ATP.Mg2+.
1Present address: Department of Biology, School of Education,Waseda University, Shinjuku-ku, Tokyo, 160 Japan. (Received February 15, 1989; Accepted April 20, 1989) 相似文献
4.
Yanagishima N.; Yoshida K.; Hamada K.; Hagiya M.; Kawanabe Y.; Sakurai A.; Tamura S. 《Plant & cell physiology》1976,17(3):439-450
The sexual agglutinability of haploid cells of heterothallicSaccharomyces cerevisiae was repressed when they were culturedin the absence of easily fermentable sugars, such as glucoseand mannose. The repression was reversed by the action of hormone-likesubstances of the opposite mating types. The substance producedby mating type cells was identical to subtsance-I which isknown to induce sexual agglutinability of inducible matingtype cells. The mating type cells produce a new hormone-likesubstance which induces or enhances sexual agglutinability of mating type cells. A crude fraction of the mating type-specific substance ( substance-I)was obtained by passing the culture filtrate of mating typecells through Amberlite CG-50 (H+ form), followed by elutionwith 1.5 M ammonia.
2 On leave from Osaka City University. (Received December 25, 1975; ) 相似文献
5.
A b-type cytochrome having an -band at 560 nm was isolated fromspinach leaves (Spinacia oleracea). A method is described forpreparing this cytochrome, cytochrome b-560 (spinach), in apurified state. The cytochrome has, in its reduced state, absorption bands at560 nm (), 530 nm (ß) and 427 nm (); and in the oxidizedstate at 562 nm (), 529 nm (ß) and 417 nm (). Thepyridine ferro-haemochrome prepared from cytochrome b-560 hadan -band at 556.5 nm, indicating the protohaem-nature of theprosthetic group. The cytochrome has an oxidation-reduction potential (E'0) of+0.13V at pH 7.0, as measured using the ferri-ferro oxalate system. The cytochrome is rapidly reduced on illumination with red orfar-red light in the presence of spinach chloroplasts and isoxidized at a slower rate in the dark. This photoreduction isinhibited by 1x106 M 3-(3,4-dichlorophenyl)-1,1-dimethylurea(DCMU). The molecular weight of the cytochrome is 30,000 asestimated by the dextran gel filtration method. (Received December 3, 1971; ) 相似文献
6.
Discovery of Natural Photosynthesis using Zn-Containing Bacteriochlorophyll in an Aerobic Bacterium Acidiphilium rubrum 总被引:1,自引:0,他引:1
Wakao Norio; Yokoi Naoto; Isoyama Naohito; Hiraishi Akira; Shimada Keizo; Kobayashi Masami; Kise Hideo; Iwaki Masayo; Itoh Shigeru; Takaichi Shinichi 《Plant & cell physiology》1996,37(6):889-893
We discovered natural photosynthesis using Zn-containing bacteriochlorophyll in an acidophilic bacterium Acidiphilium rubrum. Chemical analysisof the cell extracts gave a 13 : 2 :1 molar ratio of Zn-bacteriochlorophyll : Mg-bacteriochlorophyll : bacteriopheophytin . Most of thepigments are associated with fully active reaction center andlight-harvesting complexes analogous to those in purple photosyntheticbacteria. The finding indicates an unexpectedly wide variabilityof photosynthesis.
7Present address: Department of Ecological Engineering, ToyohashiUniversity of Technology, Tenpaku-cho, Toyohashi, 441 Japan 相似文献
7.
Various Cucurbita seed globulins showed patterns similar toone another on SDS-gel electrophoresis, and ß bandsfor unreduced globulins and , ', and ' bands for reduced ones.On gel electrophoresis in 6 M urea, reduced globulin gave twoacidic and two basic bands. These corresponded to and ' chainsand 1 and 2 chains, respectively, identified by two-dimensionalurea-SDS gel electrophoresis. The compositions of the and ßsubunits were proposed. (Received September 8, 1977; ) 相似文献
8.
9.
Temperature-dependent inhibitive actions of ,'-dipyridyl andcycloheximide on the senescence of maize leaves were studied.,'-Dipyridyl effectively inhibited the loss of chlorophyll at25?C but not at 35?C. Gycloheximide was highly effective inpreserving chlorophyll at both of 25 and 35?C. Spectral analysisof senescent leaves at 35?C in ,'-dipyridyl showed simultaneousbleaching the carotenoid and chlorophyll. (Received February 20, 1984; Accepted June 14, 1984) 相似文献
10.
Yanagishima N.; Shimizu T.; Hagiya M.; Yoshida K.; Sakurai A.; Tamura S. 《Plant & cell physiology》1977,18(6):1181-1192
We found a substance which binds to substance-I to inactivatethe biological activity of the pheromone to induce sexual agglutinabilityof a mating type cells. Both living and boiled cells of thea mating type had the substance-I-absorbing action. The absorbingaction of living cells was detected almost equally at both 0and 28?C. Cell extract of the a mating type showed the substance-I-inactivatingaction. The biological activity of substance-I inactivatedby shaking with cell-free culture medium of the a mating typewas recovered by heating at 100?C, which destroyed the inactivatingaction of the culture medium with little effect on the substance-Iactivity, indicating that a substance in the culture mediuminactivated substance-I by binding to it. This is supportedby the fact that the inactivating action completely stoppedin 30 min, leaving a considerable amount of active substance-I,when the concentration of the inactivating substance was lowcompared with that of substance-I. The ability to produce thebinding substance as specific to the a mating type. The bindingsubstance was different from the a agglutination substance responsiblefor sexual agglutination.
2 On leave from Osaka City University. (Received April 6, 1977; ) 相似文献
11.
Part of the Lysyl Residues in Wheat {alpha}-Amylase is Methylated as N-{varepsilon}-Trimethyl Lysine
Amino acid analyses of wheat -amylase purified from germinatingseeds by affinity chromatography showed a high content of amodified lysyl residue. The modified residue was identifiedas N--trimethyl lysine. The presence of trimethyl lysine in-amylase is discussed in terms of isozymes.
1 Present address: National Institutes of Health, Bldg. 10,Rm. 9B-15, Bethesda, MD 20205, U.S.A. (Received August 20, 1981; Accepted March 19, 1982) 相似文献
12.
In Vigna mungo cotyledons, the -amylase activity increased markedlyduring germination at 27°C in the dark, while the activityof other amylases was very low. The -amylase was purified from4-day-old cotyledons by affinity chromatography on epoxyactivatedSepharose 6B substituted with rß-cyclodextrin andby column chromatography on Bio-Gel P-200. Gel filtration andpolyacrylamide gel electrophoresis showed that the enzyme existsmostly as a monomer (43,000 daltons), but partially aggregatesto form dimer, trimer and further multimers. Ca2+ protectedthe -amylase against heat inactivation. Incubation of the enzymewith 5 mM EDTA or dialysis against 10 mM EDTA resulted in a5090% loss of activity. The inactivation was partiallyreversed by the addition of Ca2+. Other properties, such asthe amino acid composition, Km value, pH optimum and activationenergy were similar to those of other plant -amylases. (Received May 6, 1981; Accepted June 22, 1981) 相似文献
13.
Mitsui Toshiaki; Loboda Tadeusz; Itoh Akira; Ikarashi Taro 《Plant & cell physiology》1999,40(8):884-893
Sugar starvation-induced synthesis and extracellular liberationof -amylase molecules in suspension-cultured cells of rice (Oryzasativa L.) required Ca2+, although the level of translatable-amylase mRNA was not affected in the presence of Ca2+. Sugardepletion markedly stimulated Ca2+ uptake by rice cells andsucrose supplementation reduced it. Immunohistochemical andelectron probe microanalyzer studies indicated an apparent resemblancebetween the distribution pattern of Ca2+ and that of -amylasemolecules induced in the sugar-depleted cells. Ca2+ uptake wasreduced by sucrose, maltose, fructose, and glucose similarlyat more than 5 mM, but was unaffected by mannitol (88 mM), 6-deoxy-D-glucose(10 mM), and 3-O-methyl-D-glucose (10 mM). Furthermore, an effectiveCa2+ channel blocker, La3+ significantly inhibited the Ca2+uptake and the synthesis and extracellular liberation of -amylasemolecules in the absence of sucrose, while a general P-typeATPase inhibitor, vanadate greatly stimulated both in the presenceof sucrose. We concluded that, by controlling the Ca2+ uptake,metabolic sugars regulate the protein synthesis and posttranslationalsecretory processes of -amylase molecules in rice cells.
4 Invited research fellow of the Japan Society for the Promotionof Science. Present address: Plant Physiology Department, WarsawAgricultural University, Rakowiecka Str. 26/30 02-528 Warsaw,Poland. 相似文献
14.
Nucleoside triphosphate(NTP)-binding proteins were detectedin the crude extract of mycelia of Neurospora crassa, whichwas treated with 1% Lubrol PX and fractionated by gel filtration.Protein fractions showing the capacity to bind [35S]ATPS or[35S]GTPS were designated as AGN1 to 6. The binding of [35S]ATPSor [35S]GTPS was prevented in the presence of 0.1 mM ATP orGTP except that in fractions AGN1 and 2, the presence of GTPstimulated the binding of [35S] ATPS to ATP(NTP)-binding proteins.ATP or GTP was 1 to 2 orders of magnitude more effective thanCTP or UTP in preventing the binding of [35S]GTPS in AGN1, 2and 5. Among these fractions AGN1, 2, 5 and 6 showed activityto hydrolyze 1 nM [32P]ATP or [32P]GTP. NTP-bindingproteins bound with [35S]ATPS or [35S]GTPS had lower apparentmolecular weights than the same proteins without bound nucleotide.Proteins bound with [35S]ATPS or [35S]GTPS and those [32P]ADP-ribosylatedby endogenous ADP-ribosyl transferase in each fraction wereanalyzed by SDS-PAGE. About 20 species of ATP or ATP-GTP-bindingproteins were detected, several of which were ADP-ribosylated.The binding of [35S]ATPS or [35S]GTPS to NTP-binding proteinswas confirmed by the comparison of non-boiled and boiled samplesimmediately before loading to SDS-PAGE. ATP, GTP, CTP or UTPat the concentration of 0.1 mM effectively removed [33S]ATPSor [35S]GTPS bound to NTP-binding proteins. (Received December 10, 1990; Accepted April 18, 1991) 相似文献
15.
A microsomal preparation from the aleurone layer pre-treatedwith GA or H-ol had the ability to synthesize -amylase whenit was incubated with an appropriate medium. -Amylase synthesiswas inhibited by the addition of p-fluorophenylalanine or bypre-treatment with RNase. The synthesized -amylase was separatedinto three isozymes by disc-electrophoresis (Received July 25, 1970; ) 相似文献
16.
The senescence of maize and hydrangea leaves after being detachedand kept in the dark was studied in terms of the loss of chlorophyll.Chlorophyll was more rapidly degraded in maize than hydrangeaduring the incubation period in the dark. The loss of chlorophyllin the dark was effectively inhibited in both plants by ,'-dipyridyland o-phenanthroline at concentrations between 0.01 and 0.1mM. Three other chelators of iron produced lesser inhibitionand only at higher concentrations. EDTA prevented the loss ofchlorophyll in maize leaves at concentrations above 10 mM, butdid not do so in hydrangea leaves. Detached leaves floated on EDTA, ,'-dipyridyl or o-phenanthrolinesolutions and exposed to light exhibited a marked bleaching.The bleaching was partially inhibited by applying ascorbic acid. (Received December 26, 1981; Accepted October 18, 1982) 相似文献
17.
An -glucan was isolated from 11-day-old suspension-culturedrice cells by extraction with hot Na-phosphate buffer (pH 6.8).The -glucan had []D=+234? (C = 0.14, in water) and its averagemolecular weight was estimated to be about 1.4 ? 104, basedon elution characteristics on acalibrated Sepharose CL-6B column.Upon partial acid hydrolysis, the -glucan gave mainly malto-oligosaccharides.The maximum absorption of the iodine complex of the -glucanin the presence of Na2SO4 was at 470 nm. The results of hydrolysisby , ß- and iso-amylases and methylation analysisindicated that the isolated -glucan is a highly branched polysaccharidewith an average chain length of 9. The exterior and interiorchain lengths of the -glucan were calculated to be 5 and 3,respectively. (Received July 23, 1986; Accepted February 7, 1987) 相似文献
18.
Fidgeon, C. and Wilson, G. 1988. Uptake and accumulation ofa-naphthalene acetic acid by cell suspensions of Galium mollugoL.J. exp. Bot. 39: 241-249. Galium mollugo cell suspensions require -NAA for continued growthand cell division. The kinetics of -NAA uptake from the medium(B5) by Galium cells was assessed using 1-14C -NAA in a standardratio of cells to medium (0.25 g: 2.5 cm3). It was found thatthe uptake of -NAA was rapid, over 90% being taken up within4 h. Cells which had accumulated -NAA for 4 h or more did notrelease it back into the medium. It was found that Galium cellsaccumulated -NAA against a significant concentration gradient;suggesting the participation of an active component in the uptakemechanism. The effect of free-space and surface adsorption onthe uptake of -NAA was determined by means of a repeated washtechnique. These two factors were found to be of importanceonly during the first hour of uptake. Neither dead cells norplasmolysed cells absorbed -NAA. It is clear that, in the normal growth cycle, Galium cells cantake up the available -NAA within 3 or 4 h of inoculation andthat this can stimulate a cell division response of 3-4 generationsover the subsequent 14 d. Key words: Galium, cell suspension, -naphthalene acetic acid 相似文献
19.
Glycogen granules were isolated from the photosynthesizing cellsof purple sulfur bacterium, Chromatium strain D, and the chemicalstructure was studied by enzymic hydrolysis using -and ß-amylasesand pullulanase. The end-group assay of the bacterial glycogenby periodate oxidation gave the following analytical data: (average chain length), 11; ICL (interiorchain length), 3; and ECL (exterior chain length), 7. We concludethat the Chromatium glycogen is a glycogen- and amylopectin-type-glucan. Intracellular accumulation of glycogen granules inthe bacterial cells harvested at different growth stages wasexamined by electron microscope observation.
1This research was supported in part by a research grant fromthe Ministry of Education of Japan (No. 758036). (Received February 9, 1973; ) 相似文献
20.
Cell walls of 4-day old rice seedlings were extracted successivelywith ammonium oxalate-oxalic acid, 4% KOH and 24% KOH. A rß-D-glucanpreparation and a xyloglucan preparation were isolated fromthe 4% KOH extract and 24% KOH extract, respectively. Methylationanalysis and enzymic degradation studies of the polysaccharidesshowed that the former was built up predominantly of repeating-oligosaccharideunits of 3-O-rß-cellobiosyl-D-glucose and 3-O-rß-cellotriosyl-D-glucosein a molar ratio of 2.6 : 1.0, and the latter was of repeating-oligosaccharideunits of -D-xylosyl-(16)-rß-D-glucosyl-(14)-[-D-xylosyl-(16)]-rß-D-glucosyl-(14)-D-glucose,-D-xylosyl-(16)-rß-D-glucosyl-(14)-D-glucose and cellobiose.
1 Present address: Department of Botany, Iowa State University,Ames, Iowa 50011, U.S.A. (Received August 29, 1981; Accepted January 12, 1982) 相似文献