A method was devised to utilize the Δ4-3-ketone structure of steroids to obtain a functional group at the 6 position which could be conjugated to proteins. The bis ethylene ketal of progesterone was formed and the resulting Δ5 double bond was subjected to epoxidation. The 5α,6α-epoxide formed was opened with allyl magnesium bromide after which the terminal carbon-carbon double bond was oxidized to provide a carboxyl group which could be coupled to the free amino groups of proteins.The 6α and 6β carboxymethyl progesterone derivatives formed by this method were coupled to bovine serum albumin (BSA) using tributyl amine and -butyl chlorocarbonate. The 6α conjugate averaged 19 residues per molecule of BSA and the 6β, 24 residues per BSA. Antisera to the conjugates produced in rabbits showed very little cross-reaction with steroids which differed from progesterone at positions other than C-5 or C-6. There appeared to be very little difference between the specificities of the 6α and 6β antisera. 相似文献
Partial sialylation of biantennary and triantennary glycopeptides of α1-acid glycoprotein using colostrum β-galactosideα(2→6) sialyltransferase followed by high resolution 1H-NMR spectroscopic analysis of the isolated products enabled the assignment of the branch as the most preferred substrate site for sialic acid attachment. The branch appeared to be much less preferred and the Galβ(1→4)GlcNAcβ(1→4)Manα(1→3)Man sequence of triantennary structures was of intermediate preference for the sialyltransferase. The specificity of the β-galactoside α(2→6) sialyltransferase is thus shown to extend to structural features beyond the terminal -acetyllactosamine units on the oligosaccharide chains of serum glycoproteins. 相似文献
Repeated Biogel P6 chromatography of the urine from a patient with fucosidosis yielded several fractions containing fucosyloligosaccharides and glycopeptides. Two of these were shown by 1H nuclear magnetic resonance (1H-n.m.r.) spectroscopy and permethylation analysis to have the following structures respectively: (I) αfuc (1→3) [βgal (1→4)] βglcNAc (1→2) αman () βman (1→4) glcNAc and (II) αfuc (1→3) [βgal (1→4)] βglcNAc (1→2) αman () βman (1→4) βglcNAc (1→4) [αfuc ()] βglcNAc-Asn. 相似文献
Fluorescein isothiocyanate (FITC) was conjugated to bovine serum albumin (BSA) and the properties of the conjugate were analyzed chromatographically, electrophoretically, and immunoelectrophoretically. The conjugate was shown to be a stable molecule which retains its integrity even in in vivo experiments. It has an average degree of saturation, , which makes it sufficiently fluorescent as a tracer in transport studies. 相似文献
Three forms of lysing yeast cell walls from Rhizoctonia solani were separated by precipitation with ammonium sulfate and by successive chromatographies on CM Bio-Gel A and Bio-Gel P-60 or P-30, and were finally purified by substrate affinity chromatography on short-chain pachyman-AH-Sepharose CL 6B column. Each preparation was found to be homogeneous on gel filtration and by electrophoresis on acrylamide gel with sodium dodecyl sulfate. They exhibit high activity against insoluble pachyman, but only restricted activity against soluble short-chain pachyman. In the affinity chromatography, three enzymes were found to be strongly absorbed on the column, so that they could be easily eluted with substrate solution using biospecific counter-ligand. It was thus revealed that covalent binding of such a soluble glucan to aminohexyl-Sepharose provides a useful carrier for separation of lysing yeast cell walls. 相似文献
α-(1→2)--Fucosidase, β--galactosidase and galactose oxidase are sterically hindered by certain types of branching in the oligosaccharide chains. 1) β--Galactosidase will not cleave galactose when the penultimate sugar carries a sialic acid residue as in I. 2) Galactose Oxidase will not oxidize the galactose residue in trisaccharide I but will in II. Moreover, neither galactose nor -acetylgalactosamine, glycosidically bound as in III, is susceptible to oxidation with galactose oxidase until the α-(1→2) linkage between them is cleaved by . 3) α-(1→2)--Fucosidase action is inhibited by or galactosyl residue, as in III and IV. Removal of the terminal sugars makes the fucosyl residue susceptible to fucosidase action. 相似文献
Fibroblasts from a patient with mannosidosis were grown in a medium containing a radioactive monosaccharide (D[U-14C]mannose or ). An accumulation of radioactive material was observed. It was possible to prevent the accumulation to a certain degree by the addition of human liver α-D-mannosidase to the fibroblast medium. After six days of fibroblast culture the majority of the accumulated material had a molecular weight in the oligosaccharide range and was stationary during high-voltage electropresis. Paper chromatography of the stationary material separated three radioactive compounds with the same chromatographic mobilities as the oligosaccharides (II), and (III) previously isolated from the urine of patients with mannosidosis. Degradation of the three radioactive compounds with jack bean α-mannosidase gave D-mannose and a disaccharide (containing D-mannose and ). Thus the three main compounds observed in the fibroblast from patients with mannosidosis are most probably identical to the oligosaccharides I–III. 相似文献
Human milk β-N-acetylglucosaminide β1 → 4-galactosytransferase (EC 2.4.1.38) was used to galactosylate ovine submaxillary asialomucin to saturation. The major [14C]galactosylated product chain was obtained as a reduced oligosaccharide by β-elimination under reducing conditions. Analysis by Bio-Gel filtration and gas-liquid chromatography indicated that this compound was a tetrasaccharide composed of galactose, N-acetylglucosamine and reduced N-acetylgalactosamine in a molar ratio of 2:0.9:0.8. Periodate oxidation studies before and after mild acid hydrolysis in addition to thin-layer chromatography revealed that the most probable structure of the tetrasaccharide is . Thus it appears that Galβ1 → 3(GlcNAcβ1 → 6)GalNAc units occur as minor chains on the asialomucin. The potential interference of these chains in the assay of α-N-acetylgalactosaminylprotein β1 → 3-galactosyltransferase activity using ovine submaxillary asialomucin as an receptor can be counteracted by the addition of N-acetylglucosamine. 相似文献
1-trans-Parinaroyl-2-linoleoyl-sn-glycero-3-phosphocholine (1–18:4-2-18:2-GPC) was synthesized from lecithin and parinaric acid by the following route: . The identity of I, II and III was established by fast atom bombardment (FAB) mass spectrometry of the intact molecules as well as electron impact (E1) mass spectrometry of the corresponding O-TMS derivatives obtained after phospholipase C treatment and silylation. Temperature dependent phase transition of phospholipid liposomes was performed in the presence of III. 相似文献
The linkage pattern of the K6-antigen was investigated using material from the urinary pathogen, LP 1092. The polysaccharide consists of ribose and 3-deoxy--2-octulosonate (KDO) in a ratio of 2:1. Colorimetric procedures, Smith degradation, methylation analysis, and nuclear magnetic resonance spectroscopy were applied to the whole polysaccharide and to a trisaccharide “repeating unit” obtained by mild-acid catalyzed hydrolysis. Together, the data are compatible only with a branched chain structure …… 相似文献
The capsular polysaccharide from Klebsiella K44 has been investigated by the techniques of methylation, base-catalyzed elimination, Smith degradation, and partial hydrolysis. The last-named yielded an oligosaccharide corresponding to one repeating unit. The anomeric configutations of the sugar residueswere determined by 1H- and 13C-n.m.r. spectroscopy. The polysaccharide has a fractional acetyl content and is the first in this series to be based on a linear, pentasaccharide repeating unit. 相似文献
A gas chromatography method for the determination of free and bound vanilmandelic acid (VMA) in pig urine and chicken feces has been developed. The method consisted of extraction of the free or bound acids by ethyl acetate under acidic conditions. The ethyl acetate extracts were dried under nitrogen, followed by complete silylation of the phenolic and carboxylic acid groups with BSA (N,O)-bis (trimethylsilyl) acetamid. The solution was distilled at 180°C in a sealed glass tube after which the sample was injected on a stainless steel column (6 ft × .125 in. o.d.) containing 4% SE-30 on mesh chromosorb GHP. The recovery of the urinary VMA was 82%, and the fecal VMA was 84% through the outlined procedures. Pigs ranging in age from 8 to 12 weeks were found to excrete with no significant difference between the free and bound. Commercial laying hens excreted bound VMA in a range of with a ratio of 1:3. 相似文献
A fucose-containingceramide octadekahexoside exhibiting blood-group (A+H) activity has been isolated from hog gastric mucosa. Based on the results of partial acid hydrolysis, sequential degradation with specific glycosidases, oxidation with periodate and chromium trioxide, and permethylation analysis, we propose that the carbohydrate chain of this fucolipid contains four branches. Two of the branches are terminated by βGall→4βGlcNAc, one by and one by . 相似文献
Partial acid hydrolyzates of the extracellular polysaccharide from Porphyridiunm cruentum yield three disaccharides and two uronic acids. These constitute all of the uronic acid in the polymer. The novel disaccharides are 3-O-(α--glucopyranosyl- uronic acid)--galactose, 3-O-(2-O-methyl-ca-glucopyranosyluronic acid)-- galactose, and 3-0-(2-0-methyl-a--glucopyranosyluronic acid)--glucose. The polyanion of high molecular weight contains - and -galactose, xylose, -glucose, -glucuronic acid and 2-O-methyl-D-glucuronic acid, and sulfate in molar ratio (relative to -glucose) of 2.12:2.42:1.00:1.22:2.61. Preliminary periodate-oxidation studies suggest that the hexose and uronic acids are joined to other residues by ( 1→3) glycosidic linkages. About one-half of the xylose residues are (1→3)-linked. 相似文献
(1→3)-β-D-Glucans of various degrees of polymerization were prepared by degradation of a gel-forming D-glucan with formic acid. The degraded D-glucans were separated into a water-soluble fraction (soluble D-glucan) and an insoluble fraction (insoluble D-glucan). Both D-glucans were further fractionated. The optical rotation including determination of the o.r.d. curves of the fractions and of the original gel-forming D-glucans was measured at various sodium hydroxide concentrations (0–5M). The results indicate that (1→3)-β-D-glucans of n below ca. 25 (the soluble D-glucan) took a disordered form in both neutral and alkaline solutions, whereas the D-glucans of higher n (the insoluble and the original D-glucans) took an ordered structure in dilute alkaline solution (0.1M). The proportion of ordered structure in the insoluble D-glucan increases with n to attain a maximum value at a n of around 200; this may be the lower limit of n to permit gel formation in neutral media. The formation of complexes with Congo Red in alkaline solutions by the soluble and the insoluble D-glucans supports the same conclusions. 相似文献
The products of nitrous acid deamination of per-O-methylated 2-amino-2-deoxy-d-glucitol and and its per-O-methylated derivative have been characterized by g.l.c.—mass spectrometry after treatment with sodium borodeuteride and further substitution by acetylation, methylation, or (trideuteriomethyl)ation. The results confirm that the most important reaction pathway (1) involves a 1 → 2-hydride shift to give , but that significant side-reactions include (2) solvolytic displacement at C-2, (3) a 3 → 2-hydride shift, to give , and (4) a C-4→C-2 migration to give and -d-arabinose. Reactions (3) and (4) result in elimination of the original 3-O-substituents, with the exposure of new reducing groups, from oligosaccharides terminated by 3-O-substituted 2-amino-2-deoxyhexitols. 相似文献
The structure of the oligosaccharide units of the glycoproteins of Mr 36,000 and 62,000 isolated from alveoli of patients with alveolar proteinosis have been determined by one- and two-dimensional 1H NMR spectroscopy at 500 and 360 MHz. Bi-, tri-, and tetraantennary glycans of N-acetyllactosaminic type have been found in high percentage. They are 1 → 6 monofucosylated and fully sialylated, the ratio increasing with increasing degree of branching. 相似文献
The chloroplasts from wheat leaves greened under intermittent illuminations (1 ms in duration) at long intervals (5 min) are capable of photoreducing DCIP (2, 6-dichlorophenolindophenol) with diphenylcarbazide as an electron donor but are incapable of photoreducing DCIP with water as the donor. On exposure of such intermittently illuminated leaves to flashes spaced at intervals of less than 10 s, the delayed light emission from the leaves was greatly enhanced in parallel with the generation of Hill activity. The mechanism of this photoactivation was studied by following the changes of the delayed emission from intermittently illuminated leaves exposed to short-interval flashes programmed in various ways. Analysis of the kinetic data indicated that the photoactivation involves three consecutive photoreactions with a rate-limiting dark reaction between them; P-light → A0-light → A1-dark → A2-light → A3 in which P is a precursor convertible to A0, the first intermediate with a longer lifetime of and A3 is the final activated compound or state converted by short-interval flashes from A0 through A1 and A2, two other intermediates with shorter lifetimes of and 5 s, respectively. 相似文献
The effect of chlorophenoxyisobutyrate, a hypolipidemic drug that decreases plasma free fatty acids, triglycerides, and cholesterol, on the partitioning of [14C]-palmitate between hexane and bovine serum albumin was studied at 37°. In this system, hexane served as a hydrophobic trap for free fatty acids displaced from BSA by chlorophenoxyisobutyrate, allowing less than 0.3% to remain in the aqueous phase. As the concentration of chlorophenoxy isobutyrate was raised from 0.4 to 3.2 mM, there was a progressive displacement of palmitate from the [14C]-palmitate-BSA complex into hexane, the magnitude being dependent on the initial value (moles palmitate bound/mole BSA). Beginning with [14C]-palmitate in hexane, chlorophenoxyisobutyrate (2 mM) decreased the moles palmitate bound/mole of BSA by 16% at = 0.2, and 34% at = 3.0. 相似文献