共查询到20条相似文献,搜索用时 31 毫秒
1.
The conformational properties of the oligosaccharide chain of GM1 ganglioside containingN-glycolyl-neuraminic acid, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer, were studied through NMR nuclear Overhauser effect investigations on the monomeric ganglioside in dimethylsulfoxide, and on mixed micelles of ganglioside and dodecylphosphocholine in water. Several interresidual contacts for the trisaccharide core--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-were found to fix the relative orientitation of the three saccharides, while the glycosidic linkage of the terminal -Gal-was found to be quite mobile as the -Gal-(1-3)--GalNAc-disaccharide exists in different conformations. These results are similar to those found for two GM1 gangliosides containingN-acetyl-neuraminic acid and neuraminic acid [1].Abbreviations Ganglioside nomenclature is in accordance with Svennerholm [23] and the IUPAC-IUB Recommendations [24] GM3(Neu5Ac)
II3Neu5AcLacCer, -Neu5Ac-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer
- GM3(Neu5Gc)
II3Neu5GcLacCer, -Neu5Gc-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer
- GM1(Neu5Ac)
II3Neu5AcGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- GM1(Neu5Gc)
II3Neu5GcGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- GM1(Neu)
II3NeuGgOse4Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu-(2-3)]--Glc-(1-1)-Cer
- GD1a
IV3Neu5AcII3Neu5AcGgOse4Cer, -Neu5Ac-(2-3)--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- GalNAc-GD1a
IV4GalNAcIV3Neu5AcII3Neu5AcGgOse4Cer, -GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer
- Neu
neuraminic acid
- Neu5Ac
N-acetyl-neuraminic acid
- Neu5Gc
N-glycolyl-neuraminic acid
- Cer
ceramide 相似文献
2.
Summary A grpE mutation of Escherichia coli K12, which blocks DNA replication of the phage (Saito and Uchida, 1977), was mapped at 56 min on the standard genetic map. A transducing phage, grpE22, carrying the wild type allele of the grpE gene was constructed in vitro. Structures of grpE22 and its viable deletion derivatives were determined by electron microscopic analyses of appropriate heteroduplexes. Proteins coded by the bacterial DNA incorporated into the transducing phages were detected by two-dimensional gel electrophoresis. The results showed that the product of the grpE gene is a weakly acidic protein of molecular weight 24,000. Structural genes for two ribosomal proteins, rplS (L19) and rpsP (S16) were also shown to be carried by grpE22. 相似文献
3.
Kang NY Choi YL Cho YS Kim BK Jeon BS Cha JY Kim CH Lee YC 《Biotechnology letters》2003,25(14):1165-1170
A gene (pagA) encoding -agarase from Pseudomonas sp. SK38 was cloned and expressed in Escherichia coli. The structural gene consists of 1011 bp encoding 337 amino acids with a predicted molecular weight of 37326 and has a signal peptide of 18 amino acids. The deduced amino acid sequence showed 57% and 58% homology to -agarase from Pseudoalteromonas atalntica and Aeromonas sp., respectively. The recombinant enzyme was purified and biochemically characterized. The enzyme had maximum activity at pH 9 and 30 °C. It was stable at pHs from 8 to 9 and below 37 °C. 相似文献
4.
Two branched decaglycosylceramides, apparently identical to those identified in the small intestine of adult rats [Breimer ME, Falk K-E, Hansson GC, Karlsson K-A (1982) J Biol Chem 257:50–59], were absent during the three weeks following birth. They appeared abruptly at around 21 days. After their appearance, their tissue concentration and their base composition did not change during development. Their fatty acids were non-hydroxylated and the percentage of C22–C24 fatty acids, which was low at 24 days, increased and reached 48.6% by 27 days.Nomenclature Gal1-4Gal1-4GlcCer
Globotriaosylceramide (GbOse3Cer)
- Il3NeuAc-LacCer
MM3-ganglioside
- GalNAc1-3Gal1-4Gal1-4GlcCer
globoside (globotetraosylceramide, GbOse4Cer) 相似文献
5.
J. M. Poulos R. E. Allan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,78(3):359-364
Summary Crown position affects winter survival of fallsown wheat (Triticum aestivum L.) Direct or indirect selection for crown depth has been little practiced. Reports have suggested that short subcrown internode length was closely related to semidwarf plant height and that semidwarfism was related to poor emergence. This study determined the relationships among crown depth, plant height, and emergence rate index in three wheat populations. The efficiency of evaluating crown placement in the field was examined and additional information was obtained on its genetic control. The F2-derived F4 and F5 lines from the crosses of female parents Daws, Nugaines, and Stephens with male parent Selection 7952 were planted at Central Ferry and Pullman, Washington, respectively. Correlations from each population indicated that crown depth and subcrown internode length were not closely associated with plant height and emergence rate index. Crown depth was a more reliable indicator of crown placement than subcrown internode length. Adjustment of the data for seed depth differences was essential for evaluating subcrown internode length but less important for evaluating crown depth. After adjustment for seed depth, narrow-sense h
2 values for subcrown internode length and crown depth were 0.25–0.41. Crown depth and subcrown internode length were inherited as quantitative traits in phenotypes that expressed variable dominance. Modest gains due to selection for crown depth were achieved.Contribution from USDA-ARS and College of Agriculture and Home Economics Research Center, Washington State University, Scientific Paper No. 7795 相似文献
6.
Jan B L Damm Hans Voshol Karl Hård Johannis P Kamerling Gijs W K Van Dedem Johannes F G Vliegenthart 《Glycoconjugate journal》1988,5(3):221-233
TheN-linked carbohydrate chains of the-subunit of highly purified urinary human chorionic gonadotropin have been re-investigated. The oligosaccharides were released enzymatically by peptide-N
4-(N-acetyl--glucosaminyl)asparagine amidase-F, and fractionated by a combination of FPLC and HPLC. As a result of the application of improved fractionation methods, apart from the earlier reported carbohydrate chains, also small amounts of trisialo tri- and tri-antennary oligosaccharides were found. The primary structures of the latter carbohydrate chains have been determined by 500-MHz1H-NMR spectroscopy to beAbbreviations hCG
human chorionic gonadotropin
- hCG-
-subunit
- hCG-
-subunit
- PNGase-F
peptide-N
4-(N-acetyl--glucosaminyl)asparagine amidase-F (E.C. 3.5.1.52)
- endo-F
endo--N-acetylglucosaminidase-F (E.C. 3.2.1.96)
- SDS
sodium dodecyl sulphate
- PAGE
polyacrylamide gel electrophoresis
- CBB
coomassie brilliant blue R 250
- GlcNAc
N-acetylglucosamine
- NeuAc
N-acetylneuraminic acid
- Man
mannose
- Gal
galactose
- Fuc
fucose 相似文献
7.
A. W. Schram E. J. M. Al N. Douma L. M. V. Jonsson P. de Vlaming A. Kooi G. J. H. Bennink 《Planta》1982,155(2):162-165
Limbs of flower buds from Petunia hybrida were investigated for -glucosidase activity with dihydroflavonol-glucosides and 4-methyl-umbelliferyl--D-glucoside as substrates. Dihydroflavonol-glucoside -glucosidase is localized in the cell wall. This activity has an acid pH optimum and is also active toward 4-methyl-umbelliferyl--glucoside. Besides this activity a neutral -glucosidase is present. This activity is soluble and is not active toward dihydroflavonol-glucosides. Using starch gel electrophoresis it was shown that no difference in -glucosidase activity is present between mutants able to convert dihydroflavonols into anthocyanins and mutants accumulating dihydroflavonol-glucosides. It is concluded that -glucosidase activity is not involved in anthocyanin synthesis.Abbreviations 4MU--glc
4-methylumbelliferyl--D-glucopyranoside
- dHQ-7-g
dihydroquercetin-7-glucoside
- dHQ-4-g
dihydroquercetin-4-glucoside
- dHM-4-g
dihydromyricetin-4-glucoside
Deceased 相似文献
8.
N. T. Chang R. E. Lynch F. A. Slansky B. R. Wiseman D. H. Habeck 《Entomologia Experimentalis et Applicata》1987,45(1):29-35
Food utilization by larvae of the fall armyworm (Spodoptera frugiperda [J. E. Smith]) (Lepidoptera: Noctuidae), showed greater consumption of corn (Zea mays L.) than pinto bean diet, Tifton 10, or Coastal bermudagrass (Cynodon dactylon [L.] Pers.). Transfer of larvae from diet to susceptible grasses such as corn, Tifton 10 or Coastal produced differences in growth rates as a result of food consumption rates. Transfer of larvae from diet to resistant grasses such as common centipedegrass (Eremochola ophiuroides [Munro] Hack) Tifton 292 bermudagrass, and zoysiagrass (Zoysia sp.) reduced larval growth as a result of low consumption rates and/or greater metabolic expenditures. Larvae initially fed Tifton 10, Coastal, or centipedegrass before feeding on corn grew significantly faster than when they fed continuously on corn.
Résumé Des chenilles de S. frugiperda ont consommé plus de maïs (Zea mays), que d'un régime à base de Phaseolus vulgaris de la variété Pinto, ou de Tifton 10, ou de Cynodon dactylon de la variété Coastal. Des chenilles, transférées du régime artificiel sur des plantes sensibles comme le maïs, le Tifton 10 ou le Coastal, ont présenté des taux de croissance différents provenant de modifications de leur consommation. Le transfert du régime à des plantes résistantes, telles que Eremochola ophiuroides, Tifton 292, C. dactylon et Zoysia sp., a entraîné une diminution de la croissance larvaire par suite d'une plus faible consommation et/ou de dépenses métaboliques plus élevées. Des chenilles ayant consommé du Tifton 10, du Coastal ou de l'E. ophiuroides avant de consommer du maïs, se sont développées significativement plus vite que celles qui s'étaient alimentées continuellement sur maïs.相似文献
9.
Photosynthetic carbon fixation of freshly isolated cells of Prochloron, the symbiont of Lissoclinum patella, proceeded at high rates (80–180 mol O2·mgChl-1·h-1) in buffered seawater and showed a typical light response, saturating at about 300 E·m-2·s-1. However, in NaCl solutions osmotically equivalent to seawater CO2-dependent O2 evolution ceased or was severely inhibited. Hypotonic or hypertonic conditions induce degrees of swelling or shrinkage, respectively, apparently causing similar increases in the plasmamembrane's permeability to ferricyanide. Initially high, but rapidly declining, rates of electron transport were observed when the cells were suspended in distilled water. This inhibition was not caused by rupture of the cells, indicating instead diffusive loss of some essential factor(s) which normally exchange easily and rapidly between the cells and/or the host environment. Such rapid exchange may be part of the mechanism of this symbiosis and, if not adequately understood, may frustrate attempts to culture Prochloron away from its host.Abbreviations HEPES
N-2-hydroxyethyl piperazine-N-2 ethane sulphonic acid
- EPPS
N-2-hydroxyethyl propane sulphonic acid
- FeCN
potassium ferricyanide
- DBMIB
2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone
- DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- TMPD
N,N,N,N,-tetramethyl-p-phenylenediamine
- DCIP
2,6-dichlorophenol-indophenol
- MV
methylviologen
- PS
photosystem
- Chl
chlorophyll
Publication No. 219 of the Australian Institute of Marine Science 相似文献
10.
CD3 is an essential component of the CD3-TCR complex. In this report, we describe the cloning, characterization, and expression analysis of the CD3 and CD3/ chain genes from fugu, Takifugu rubripes. Two distinct CD3 homologue cDNAs, designated as CD3-1 and CD3-2, and a CD3/ homologue cDNA were isolated from the fugu thymus. The deduced amino acid sequences of these cDNAs exhibit conserved essential CD3 chain motifs and overall structures. RT-PCR analysis demonstrated that the CD3 and CD3/ genes were expressed in lymphoid organs (e.g. thymus, head kidney, trunk kidney and spleen), mucosal tissues (gill, skin, and intestine), and peripheral blood leucocytes (PBL). The CD3 and TCR genes were expressed only in the surface IgM– population, which were separated from PBL using an anti-fugu IgM monoclonal antibody. In addition, in situ hybridization confirmed that CD3-expressing cells were distributed randomly in the head kidney, trunk kidney, and spleen, but in the thymus were restricted to the lymphoid outer zone and epithelioid inner zone only. Collectively, these results suggest that CD3 molecules are useful markers for the identification of T cells in teleost fish. The present study thus provides a critical step in identifying T cells in this model organism.Nucleotide sequence data reported in this paper are available in the DBJ/EMBL/GenBank databases and have been assigned the accession numbers AB166798 (CD3-1), AB166799 (CD3-2), and AB166800 (CD3/). 相似文献
11.
Bimolecular oxygenation of tri-liganded R-state human hemoglobin (HbA) is described by bi-exponential kinetics with association rate constants k
= 27.2 ± 1.3 (M·sec)-1 and k
= 62.9 ± 1.6 (M·sec)-1. Both the observed processes have been assigned to the bimolecular oxygenation of - and -subunits of the native tetrameric protein by molecular oxygen. The quantum yields of photodissociation within the completely oxygenated R-state HbA are
= 0.0120 ± 0.0017 and
= 0.044 ± 0.005 for - and -subunits, respectively. The oxygenation reactions of isolated PCMB- and PCMB-hemoglobin chains are described by mono-exponential kinetics with the association rate constants k
= 44 ± 2 (M·sec)-1 and k
= 51 ± 1 (M·sec)-1, respectively. The quantum yields of photodissociation of isolated PCMB- and PCMB-chains (0.056 ± 0.006 and 0.065 ± 0.006, respectively) are greater than that observed for appropriate subunits within the R-state of oxygenated HbA. 相似文献
12.
Chrysobactin (-N-(2,3-dihydroxybenzoyl)-d-lysyl-l-serine), a siderophore that is essential for systemic virulence by plant pathogenic Erwinia chrysanthemi, was synthesized with high diastereomeric purity. Chrysobactin was prepared by coupling the N-hydroxysuccinimide ester of -N-(2,3-dibenzyloxybenzoyl)--N-Cbz-d-lysine with l-serine benzyl ester followed by deprotection via hydrogenolysis. Optically pure chrysobactin was obtained with 98% overall yield. A monoclonal antibody to ferric chrysobactin was developed and characterized as IgM. The antibody reacts with chrysobactin, ferric chrysobactin and less strongly with ferric dihydroxybenzoic acid. The antibody reacts weakly with the siderophores ferrichrome, A, ferric pseudobactin and ferric rhodotorulic acid. This antibody was used in a competitive immunoassay to detect ferric chrysobactin at 10–8 to 10–10 mol. This immunoassay may provide a useful method for the detection of chrysobactin in plant samples. 相似文献
13.
The turgor-homeostat model of assimilate efflux from coats of developing seed of Phaseolus vulgaris L. was further characterised. The turgor pressure (P), the volumetric elastic modulus () and hydraulic conductivity (Lp) of the seed coat cells responsible for assimilate efflux and cotyledon storage parenchyma cells were determined with a pressure probe. In addition, turgor of the seed coat and cotyledons was estimated by measuring the osmolalities of symplastic and apoplastic fluids extracted by centrifugation. Osmolality of symplastic and apoplastic saps collected from the seed coat declined significantly over the period of seed development from a cotyledon water content of 80% to 50%. However, the difference in osmolalities of the apoplastic and symplastic saps remained relatively constant. For cotyledons, osmolality of the apoplastic sap exhibited a significant decline during seed development, while the osmolality of symplastic sap did not change significantly. Hence cotyledon P increased as the water content dropped from 80% to 50%. For both detached and attached empty seed coats, a small decrease (ca. 40mOsmol·kg–1) in the osmolality of the bathing solution, led to a rapid increase in P of cells involved in assimilate efflux (efflux cells) by about 0.07 MPa. Thereafter, cell P exhibited a rapid decline to the original value within some 20–30 min. When P of the efflux cells was reduced by increasing the osmolality of the bathing solution, P exhibited a comparable rate of recovery for attached empty seed coats but there was no P recovery to its original value in the case of detached seed coats. In contrast, the cotyledon storage parenchyma cells did not exhibit P regulation when the osmolality of the bathing solution was changed. The observations that the efflux cells of P. vulgaris seed coats can rapidly adjust their P homeostatically in response to small changes in apoplastic osmolality are consistent with the operation of a turgor-homeostat mechanism. The volumetric elastic modulus () of the seed coat efflux cells exhibited a mean value of 7.3±0.8 MPa at P=0.15 MPa and was found to be linearly dependent on cell P. The e of the cotyledon storage parenchyma cells was estimated to be 6.1±1.0 MPa at P=0.41 MPa. Hydraulic conductivity (Lp) of the seed coat cells and the cotyledon cells was (8.2±1.5) × 10–8m·s–1·MPa–1and (12.8±1.0) × 10–8 m·s–1·MPa–1, respectively. The relatively high , i.e., low elasticity, for the seed coat cell walls would ensure that small changes in water potential of the seed apoplast will be reflected in large changes in cell P. The high Lp values for both the seed coat and the cotyledon cells is consistent with the rapid changes in P in response to changes in water potential of the seed apoplast.Abbreviations LYCH
Lucifer Yellow CH
-
volumetric elastic modulus
- Lp
hydraulic conductivity
- P
turgor pressure
-
osmotic pressure
- t1/2
half-time for water exchange
The investigation was supported by funds from the Australian Research Council. We are grateful to Louise Hetherington for competent technical assistance and to Kevin Stokes for raising the plant material. 相似文献
14.
The responses of 7 genotypes of Rhodendron to culture conditions and their establishment as shoot cultures are described. The genotypes represent a broad genetic diversity in the genus. After sterilization and an acclimation period of 3 to 12 months, all the selections were established as shoot cultures on Woody Plant Medium (WPM) supplemented with N6(-2-isopenteny) adenine (2iP). Plants with strong episodic growth cycles required the longer acclimation periods. Utilizing shoots from these cultures, the response to a cytokinin series of 0 to 32 M 2iP or BAP (6-Benzylaminopurine) was analyzed. BAP proved toxic to all but the elipidote and lepidote rhododendrons (R. mucronulatum, R. x Boule de Neige, and R. x PJM); however, even with these selections, 2iP stimulated greater shoot multiplication rates. The optimum 2iP level for shoot multiplication varied little with the genotype and levels of 4 to 16 M generally proved optimal, depending on the specific selection. Adventitious shoot production was observed in 3 selections (R. canadense, R. x Boule de Neige and R. x PJM), but only at 2iP levels above 8 M. Shoot multiplication rates of 7 to 21 times were observed, depending on the selection. Using an average utilizable shoot production rate of 40 shoots per culture per 6 week subculture period, some 75,000 shoots can be generated per square meter of culture space per year. The harvested shoots (microcuttings) rooted readily out-of-culture and the resultant plants grew like seedlings. 相似文献
15.
Edwin J. Mientjes Joost H. M. van Delft Brenda M. op't Hof Jan A. Gossen Jan Vijg Paul H. M. Lohman Robert A. Baan 《Transgenic research》1994,3(1):67-69
The determination of thelacZ mutant frequency in gt10lacZ phage vectors isolated from the transgenic mouse strain 40.6 (MutaMouse), requires the screening of large numbers of phages on -galactosidase activity. Existing methods rely on distinguishing a few white plaques on X-gal containing plates amongst a multide of blue ones which is both time-consuming and expensive. The new screening method described here employs the galactose sensitiveEscherichia coli C lacZ recA galE strain into which a multicopy plasmid has been introduced, which results in over-expression of thegalK andgalT genes. In the presence of phenyl--d-galactopyranoside, a substrate for -galactosidase, this leads to the suppression of lacZ
+ phage propagation without affecting the ability of lacZ
– phages to form plaques. With this method it is possible to screen 1.5×106 phages on a single 9-cm Petri dish. Furthermore, the need for blue/white screening has been eliminated. 相似文献
16.
M. A. A. Gadallah 《Plant Growth Regulation》1996,20(3):225-236
Growth and contents of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), phosphorus (P) and sulphur (S) in shoot and root tissues of Carthamus tinctorius plants were measured at combinations of four nutrient solution osmotic potentials (s=0, -0.3, -0.6 and -0.9 MPa) induced by NaCl and CaCl treatments, three constant temperatures (T) ranging from 15 to 35°C and four abscisic acid (ABA) concentrations (0,10,50 and 100 mg L–1). Unstressed and stressed plants grown in optimal temperature conditions (25°C) maintained higher growth rates (dry mass production) than plants grown under low and high temperatures (15 and 35°C respectively). Shoot and root growth (dry mass production) were largely inhibited by salinity but the magnitude of growth inhibition was temperature dependent. Safflower plants respond to salinity stress by increases in Ca, Cl and to a lesser extent Na in their shoots and roots and by a decrease in the ratio of fresh to dry weight. The ratio of K/Na was decreased progressively on salinization. With stressed plants, ABA application reduced the toxicity of salt treatment, improved K uptake under salinity, effectively increased K/Na ratio and helped the plants to avoid Na toxicity and sometimes enhanced growth. The effect of ABA on the growth was more pronounced at optimum temperature (25°C). The association between the internal mineral element concentrations was largely affected by ABA application and temperature change but a wide fluctuation in response was noticed. The effects of single factors (s, T and ABA) on the growth and mineral contents were statistically significant. Also, bifactorial (s× T, s × ABA and T × ABA) and three factorial (s × T × ABA) interactions significantly affected the parameters. Further statistical treatment of the data (coefficient of determination 2) led to four important findings: (1) Salinity (s) was dominant in affecting Ca and Cl contents in both shoot and root as well as root Na content. (2) Temperature (T) had a dominant effect on growth, shoot K, Mg, P, S and root P, and S contents (3) The share of s × T × ABA interaction was dominant for root Na and Mg contents. (4) The single factors and their interactions had a dual role in their subsidiary effects.Abbreviations ABA
abscisic acid
- s
osmotic potential
- 2
coefficient of determination
- F.wt
fresh weight
- d.m.
dry matter
- T
temperature
- MPa
mega pascal
- SAR
sodium adsorption ratio
- P
phosphorus
- S
sulphur 相似文献
17.
A method for long-term plant regeneration of Phaseolus coccineus L, is described. Shoot-tips and cotyledonary nodes cultured on a Murashige and Skoog medium supplemented with N6-benzylaminopurine, 10 M, and -naphthaleneacetic acid, 1M, formed multiple bud-shoots. These shoots were transferred to medium containing BAP 1 M, NAA 0.1 M, and gibberellic acid 3 M to promote shoot growth and further shoot multiplication. Rooting was achieved in medium with 11 M indole-3-acetic acid. Rooted plants grew to maturity and were fertile. Cultures have maintained their ability to regenerate plants for more than two years. A sample of 30 regenerated plants (R0) was tested for chromosome number, all of them being diploid; seven isozymatic systems were electrophpretically analyzed in 82 R0 regenerated plants. No differences were observed in their electrophoretic patterns in comparison with those shown by seedlings. Histological studies revealed the origin of buds from calluses via organogenesis.Abbreviations BAP
N6-benzylaminopurine
- 2,4-D
2,4-dichlorophenoxyacetic acid
- GA3
gibberellic acid
- IAA
indole-3-acetic acid
- MS
Murashige and Skoog (1962) medium
- NAA
-naphthaleneacetic acid
- ADH
alcohol dehydrogenase
- GOT
glutamic-oxaloacetic transaminase
- MDH
malate dehydrogenase
- 6PGD
6-phosphogluconate dehydrogenase
- PGI
Phosphoglucose isomerase
- PGM
phosphoglucose mutase
- SK
shikimate dehydrogenase 相似文献
18.
We investigated the properties of a galactosyltransferase (GalT) that is involved in the synthesis of -(14)-galactan side chains of pectins. A membrane preparation of etiolated 6-day-old soybean (Glycine max Merr.) hypocotyls transferred [14C]Gal from UDP-[14C]Gal into intact and partially hydrolyzed lupin -(14)-galactans of various chain lengths as exogenous acceptors, while activity to endogenous acceptors was negligible. Maximal activity occurred at pH 6.5 and 20–25°C in the presence of 25 mM Mn2+ and 0.75% Triton X-100. The transfer reaction onto the unmodified commercial pectic galactan (M
r>150,000) from lupin we used was very low but increased when the M
r of the galactan was reduced by partial acid hydrolysis. Among the partially hydrolyzed galactans, high-M
r (average M
r 60,000) -(14)-galactan was a more efficient acceptor [specific activity 2,000–3,000 pmol min–1 (mg protein)–1] than low-M
r (average M
r 10,000 and 5,000) polymers. Digestion of the radiolabeled product from high-M
r galactan with endo--(14)-galactanase released mainly radioactive -(14)-galactobiose and Gal, indicating that the transfer of [14C]Gal occurred through -(14)-linkages. HPLC analysis showed that the enzyme also catalyzes incorporation of Gal into pyridylaminated (PA) -(14)-galactooligomers with degree of polymerization at least 5. Gal7-PA chains were elongated by attachment of one, two, or three Gal residues leading to the formation of Gal8–10-PA.Abbreviations
AGP
Arabinogalactan-protein
-
Ara
Arabinose
-
DP
Degree of polymerization
-
GalA
Galacturonic acid
-
Gal
n
-PA
Pyridylaminated -(14)-galactooligosaccharides
-
GalT
Galactosyltransferase
-
MALDI–TOF–MS
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
-
Rha
Rhamnose
Sugars described in this paper belong to the d-series unless otherwise noted 相似文献
19.
R. Huch J. D'Haese Ch. Gerday 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1988,158(3):325-334
Summary Soluble calcium-binding proteins (SCBP) considerably different from calmodulin were purified from the body wall muscle of the earthwormLumbricus terrestris. Three isoforms were obtained with similar UV absorption spectra and amino acid compositions and an apparent molecular weight close to 20 kDa. They can be distinguished by their histidine and proline content and by their peptide maps. The tissue content, as determined by quantitative ELISA varies individually from 0.1 to 0.3 mmol kg–1. The calcium-binding property can be demonstrated by Ca2+-dependent electrophoretic mobility shift and45Ca2+ autoradiography on nitrocellulose sheets. The apparentK
D values for the SCBP-Ca2+ complex is approximately 10–7 mol l–1 as revealed by euquilibrium and flow dialysis experiments. In the presence of 1 mmol l–1 MgCl2 the maximum binding capacity of SCBP was determined to be either 2 mol Ca2+ mol–1 protein (SCBP2) or 3 mol Ca2+ mol–1 protein (SCBP3). Preliminary studies concerning the functional role of SCBP indicate that it facilitates the diffusion of Ca2+ ions by a factor of 2 and is capable of inhibiting the ATPase of isolated body wall muscle actomyosin. The results reveal that earthworm SCBP are similar to vertebrate parvalbumin and to SCBP characterized from aquatic invertebrates.Abbreviations
ABTS
2,2-azino-di-(3-ethyl)-benzothiazolinsulfonate
-
CN-PDE
3:5-cyclic nucleotide-phosphodiesterase
-
DEAE
diethylaminoethyl
-
EGTA
ethyleneglycol-bis(-aminoethyl ether)-N,N,N,N-tetraacetic acid
-
ELISA
enzyme linked immuno sorbent assay
-
HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
-
HPLC
high performance liquid chromatography
-
HRP
horseradish peroxydase
-
PAGE
polyacrylamide gel electrophoresis
-
PBS
phosphate buffered saline
-
P
i
inorganic phosphate
-
PMSF
phenylmethylsulfonyl fluoride
-
SCBP
soluble calcium-binding protein
-
SDS
sodium dodecyl sulphate
-
SPDP
N-succininydyl-3-(2-pyridyldithio)propionate
-
SR
sarcoplasmic reticulum
-
Tris
tris(hydroxymethyl)-aminomethane
-
UV
ultraviolet 相似文献
20.
Summary The left operator mutant v2s develops poorly during infection as a result of constitutive expression of the left operon. A revertant of v2s, designated iri, was found to contain an inversion of the cI region with the inversion endpoints to be within the lambda operators o
L and o
R. Formation of the inversion is facilitated by a translocation of right operator o
R
c
mutant sequence to the left operator in v2s. The inversion in iri positions wild-type o
R sequence at o
L returning control of the left operon to repression by the lambda cro repressor. 相似文献