共查询到20条相似文献,搜索用时 31 毫秒
1.
Jose O. Previato Robin Wait Christopher Jones Lucia Mendonça-Previato 《Glycoconjugate journal》1994,11(1):23-33
Mild alkaline hydrolysis of the glycophosphosphingolipids of the protozoanLeptomonas samueli liberated several phosphoinositol-containing oligosaccharides (PI-oligosaccharides), which were purified by high performance anion exchange chromatography. The oligosaccharides in the resulting four fractions were characterized by methylation analysis, fast atom bombardment mass spectrometry and two-dimensional nuclear magnetic resonance spectroscopy. The oligosaccharides contain the core structure Man(1–4)GlcN(1–6)-myo-inositol-1-OPO3, and are substituted with 2mol of 2-aminoethylphosphonate per mol of oligosaccharide. The nonreducing ends of the oligosaccharides were terminated by rhamnose branched neutral and acidic xylose-containing penta-, hexa-, hepta- and octasaccharides, of which the three most abundant were shown to have the structures:
相似文献
2.
Correlation analyses were carried out to determine relation of body temperature and respiration rate of three breeds of swine to the environmental temperature. Coefficients of regression were determined for a prediction equation of the form:
$$\begin{array}{*{20}c} {y = a + b_1 x_1 + b_2 x_2 + b_3 x_3 + b_4 x_4 + b_5 x_5 } \\ {where,y = body temperature} \\ {\begin{array}{*{20}c} {x_1 = respiration rate} \\ {x_2 = body weight} \\ {\begin{array}{*{20}c} {x_3 = sex} \\ {x_4 = environmental temperature} \\ {x_5 = x_1 x_4 } \\ \end{array} } \\ \end{array} } \\ \end{array}$$ 相似文献
3.
Robert Matthey 《Molecular genetics and genomics : MGG》1966,97(4):361-369
A sample of 12Mus (Leggada) triton Th. from the region of Bukavu (Democratic Republic of Congo) contains 5 ♂♂ and 7 ♀♀. 2N=32. All the autosomes are acrocentric. The sex-chromosomes of the ♂ are of the typeX—Y, theX beeing a big submetacentric (I.C.=0,4). Three ♀♀ possess two metacentricX, as expected. By four ♀♀, there is only one typicalX whose partner is acrocentric and as long as the long arm of a normalX. ThisX must have been arisen through the deletion of the short arm and is calledX ddc. The statistical analysis of the sample is compatible with this pattern:
$$\begin{array}{*{20}c} { \circ \circ } \\ { + + } \\ \end{array} \begin{array}{*{20}c} {X---X = 4/9} \\ {X---X_{dc} = 4/9} \\ {X_{dc} ---X_{dc} = 1/9} \\ \end{array} \begin{array}{*{20}c} { \nearrow \nearrow } \\ { \circ \circ } \\ \end{array} \begin{array}{*{20}c} {X---Y = 2/3} \\ {X_{dc} ---Y = 1/3} \\ \end{array} $$ 相似文献
4.
T. K. Chandrashekar P. J. O'malley I. Rodriguez G. T. Babcock 《Photosynthesis research》1986,10(3):423-429
The early suggestion by Lozier and Butler (Photochem. Photobiol. 17, 133–137 (1973)) that EPR Signal II arises from radicals associated with the water-splitting process in PSII has been confirmed and extended over the intervening years. Recent work has identified the Signal II radicals, \(\begin{array}{*{20}c} {\mathop D\nolimits^{\begin{array}{*{20}c} + \\ . \\ \end{array} } } \\ \end{array}\) and \(\begin{array}{*{20}c} {\mathop Z\nolimits^{\begin{array}{*{20}c} + \\ . \\ \end{array} } } \\ \end{array}\) , with plastosemiquinone cation species. In the experiments presented here we have used ENDOR spectroscopy and D2O/H2O exchange to characterize these paramagnets in more detail. The ENDOR matrix region, which arises from protons which interact weakly with the unpaired electron spin, is well-resolved at 4 K and at least seven resonances are apparent. A number of hyperfine couplings in the 3–8 MHz range are observed and are suggested to arise from methyl or hydroxyl protons which occur as substituents on the plastosemiquinone cation ring or from amino acid protons hydrogen-bonded to the 1,4-hydroxyl groups. Orientation selection experiments are consistent with these possibilities. D2O/H2O exchange shows that the D+/Z+ site is accessible to solvent. However, the exchange occurs slowly and is not complete even after 72 hours which suggests that the free radicals are functionally isolated from solvent water. 相似文献
5.
Cornelis H. Hokke Marc J. H. Roosenboom Jane E. Thomas-Oates Johannis P. Kamerling Johannes F. G. Vliegenthart 《Glycoconjugate journal》1994,11(1):35-41
The disialylated poly-(N-acetyllactosamine)-containingO-linked oligosaccharide alditols, released by alkaline borohydride treatment of the enzymicallyN-deglycosylated β-subunit of equine chorionic chonadotropin, were purified by fast protein liquid chromatography (FPLC) on Mono Q and analysed by fast ion bombardment mass spectrometry (FAB-MS) and1H-NMR spectroscopy. The identified oligosaccharide alditols have the following structure: $$\begin{gathered} Neu5Ac\alpha 2 - 3\left[ {Gal\beta 1 - 4GlcNAc\beta 1 - 3} \right]_{0 - 4} Gal\beta 1 - 4GlcNAc\beta 1 - 6 \hfill \\ \begin{array}{*{20}c} { \backslash } \\ { GalNAc - ol} \\ { /} \\ {Neu5Ac\alpha 2 - 3Gal\beta 1 - 3} \\ \end{array} \hfill \\ \end{gathered}$$ 相似文献
6.
Martha P. Brown Dimitri Toptygin K. B. Lee Theresa Animashaun R. C. Hughes Y. C. Lee Ludwig Brand 《Journal of Protein Chemistry》1998,17(2):149-159
The plant lectin Tetracarbidium conophorum agglutinin II binds to glycoproteins and glycopeptides in a structurally specific manner [Animashaun et al., (1994) Glycoconjugate J.
11, 299–303]. We have characterized the steady-state and time-resolved fluorescence of the tryptophan residues of this lectin. The fluorescence (ex = 295 nm, em = 350 nm) decay is complex and can be described by four decay times with the following values: 1 = 7.4nsec, 1 = 0.22; 2 = 2.9 nsec, 2 = 0.25; 3 = l.0 nsec, 3 = 0.34; 4 = 0.2 nsec, 4 = 0.18. The addition of a biantennary glycopeptide
to the lectin results in a quench and an 8 nm blue shift of the emission spectrum. The effect is saturable, and is described by an association constant of 1.8×105 M–1. The tryptophan fluorescence of Tetracarbidium conophorum agglutinin II may therefore be utilized to characterize thermodynamically the binding interactions between this lectin and complex glycoprotein. 相似文献
7.
The transient response method is introduced to elucidate the mechanism of reaction over immobilized enzyme. Glucose oxidation over the glucose oxidase that was immobilized on ion-exchange resin using glutaraldehyde as a linking agent is selected as an example here. The transient responses of a fixed-bed reactor to step increases and decreases in glucose, oxygen, and gluconolactone feed concentrations have been monitored and interpreted. From some responses, we have found that gluconolactone is formed in the reaction of glucose with adsorbed oxygen, while hydrogen peroxide is formed in the reaction of oxygen with adsorbed glucose. Combining all information from interpreting the responses with the literature, a mechanistic picture can be obtained as follows: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {E_{{\rm ox}} + G \to E_{{\rm red}} GL} \\ {E_{{\rm red}} GL \to E_{{\rm red}} + GL} \\ {E_{{\rm red}} + {\rm O}_2 \to E_{{\rm ox}} {\rm H}_2 {\rm O}_2 } \\ {E_{{\rm ox}} {\rm H}_2 {\rm O}_2 \to E_{{\rm ox}} + {\rm H}_2 {\rm O}_2 } \\ \end{array} $$\end{document}. 相似文献
8.
Alexander M. Mazo Vladimir S. Scheinker Lev. L. Kisselev 《Molecular biology reports》1975,2(3):233-239
The action of ribonucleases on poly and oligoribonucleotides containing cytosine bases modified by methoxyamine and bisulphite was examined. Resistance of phosphodiester bonds in (Cp)
n
Xp (where n 1 and X stands for A, G or U) to T2 RNase hydrolysis was observed if substrates were modified chemically. The phenomenon formed the basis for isolation of (Cp)
n
Xp blocks as an additional tool in sequence investigations. After modification of cytosine pancreatic RNase was unable to hydrolyse (Cp)
n
Up blocks. Therefore the specificity of pyrimidyl RNase may be narrowed to uridyl RNase.Abbreviations
cytidine modified with methoxyamine and bisulphite (5, 6-dihydro-6-sulpho-N4-methoxycytidine)
-
cytidine modified with methoxyamine (N4-methoxycytidine) 相似文献
9.
The peptide subunits of the pseudomurein, the cell-wall peptidoglycan of some methanogens, are usually composed of glutamic
acid, alanine and lysine. In order to get a more detailed picture of the biosynthetic pathway of the peptide subunit, we performed
in vitro assays. Starting from glutamic acid a pentapeptide was obtained in seven steps:
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