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Joachim Thiem - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Novel Di- and Trisaccharide Mimetics with Non-Glycosidic Amino Bridges
European Journal of Organic Chemistry, 2007Co-Authors: Janna Neumann, Saskia Weingarten, Joachim ThiemAbstract:Synthesis of novel di- and Trisaccharides using enzymatic glycosylation, Dess–Martin oxidation and reductive amination allows rapid access to the target structures. Thus, a novel class of glycomimetics was obtained having nitrogen inserted as bridging atom between two non-anomeric positions. Novel di- and Trisaccharide mimetics were designed using N-acetylglucosamine as a basis structure. A third monosaccharide unit was attached via an unnatural sugar–sugar bond without participation of the anomeric center. Their synthesis, proceeding via oxidation, glycosylation and reductive amination, required only a few steps, thus allowing rapid access to the target structures. Generation of the novel pseudo-disaccharide was achieved by Dess–Martin oxidation and a subsequent reductive amination. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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One-pot-synthesis of α-linked deoxy sugar Trisaccharides
Carbohydrate research, 1994Co-Authors: Sabine Köpper, Joachim ThiemAbstract:Abstract Various α-linked 2,6-dideoxy- ribo -Trisaccharides, models for part of the antibiotic kijanimicin, were synthesised by the N -iodosuccinimide method employing different pathways. The efficiency of a sequential synthesis suffered from side reactions of the axial HO-3, which are typical of digitoxosides. These problems did not arise in a straightforward polymerisation, performed as a one-pot-procedure. It afforded the Trisaccharide directly from the monosaccharide precursor in 30% yield. A combination of the oligomerisation pathway and the sequential synthesis led to Trisaccharides with different protecting group patterns. In these reactions different glycal and alcohol components were used and allowed to define the optimal partners in a sequential synthesis: the two components should ideally be of comparable reactivity.
Nikolay E. Nifantiev - One of the best experts on this subject based on the ideXlab platform.
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synthesis and conformational analysis of vicinally branched Trisaccharide β d galf 1 2 β d galf 1 3 α galp from cryptococcus neoformans galactoxylomannan
Organic and Biomolecular Chemistry, 2021Co-Authors: Vera S Dorokhova, Bozhena S. Komarova, Alexander S Shashkov, Alexey G Gerbst, Jose O Previato, Lucia Mendonca Previato, Andrey S Dmitrenok, Vadim B Krylov, Nikolay E. NifantievAbstract:The synthesis of a vicinally branched Trisaccharide composed of two d-galactofuranoside residues attached viaβ-(1 → 2)- and β-(1 → 3)-linkages to the α-d-galactopyranoside unit has been performed for the first time. The reported Trisaccharide represents the galactoxylomannan moiety first described in 2017, which is the capsular polysaccharide of the opportunistic fungal pathogen Cryptococcus neoformans responsible for life-threatening infections in immunocompromised patients. The NMR-data reported here for the synthetic model Trisaccharide are in good agreement with the previously assessed structure of galactoxylomannan and are useful for structural analysis of related polysaccharides. The target Trisaccharide as well as the constituent disaccharides were analyzed by a combination of computational and NMR methods to demonstrate good convergence of the theoretical and experimental results. The results suggest that the furanoside ring conformation may strongly depend on the aglycon structure. The reported conformational tendencies are important for further analysis of carbohydrate-protein interaction, which is critical for the host response toward C. neoformans infection.
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synthesis of oligosaccharides related to the hnk 1 antigen 5 synthesis of a sulfo mimetic of the hnk 1 antigenic Trisaccharide
Russian Chemical Bulletin, 2007Co-Authors: E V Sukhova, A V Dubrovskii, Yu E Tsvetkov, Nikolay E. NifantievAbstract:2-Aminoethyl 3,6-di-O-sulfo-β-D-glucopyranosyl-(1→3)-β-D-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-β-D-glucopyranoside, which is the sulfo-mimetic of the antigenic Trisaccharide HNK-1, and the corresponding monosulfates, viz., 2-aminoethyl 3-O-sulfo-and 2-aminoethyl 6-O-sulfo-β-D-glucopyranosyl-(1→3)-β-D-galactopyranosyl-(1→ 4)-2-acetamido-2-deoxy-β-D-glucopyranosides, were synthesized. 2-Azidoethyl 2,4-di-O-benzoyl-β-D-glucopyranosyl-(1→3)-2,4,6-tri-O-benzoyl-β-D-galactopyranosyl-(1→ 4)-2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranoside served as the common precursor for the sulfated Trisaccharides. This compound was synthesized according to the [2+1] pattern from monosaccharidic precursors: 3,6-di-O-acetyl-2,4-di-O-benzoyl-D-glucopyranosyl trichloroacetimidate, allyl 2-O-benzoyl-4,6-O-benzylidene-β-D-galactopyranoside, and 2-azidoethyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranoside. The structures of the glycosyl donors and glycosylation conditions were optimized for the efficient synthesis of the glucosyl-β-(1→3)-galactose disaccharide block and its subsequent transformation into the target Trisaccharide sequence.
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Synthesis of a common Trisaccharide fragment of glycoforms of the outer core region of the Pseudomonas aeruginosa lipopolysaccharide
Tetrahedron Letters, 2006Co-Authors: Bozhena S. Komarova, Yury E. Tsvetkov, Yuriy A. Knirel, Ulrich Zähringer, Gerald B. Pier, Nikolay E. NifantievAbstract:Abstract The first synthesis of the common Trisaccharide of glycoforms of the outer core region of the Pseudomonas aeruginosa lipopolysaccharide is reported. A fully protected Trisaccharide precursor was prepared via a highly efficient α-(1→4)-glucosylation of a β-(1→3)-linked 6-O-benzyl-2-azido-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-β- d -glucopyranosyl)-α- d -galactopyranoside. In contrast, an alternative sequence of glycosylations, which involves β-glucosylation of an α-(1→4)-linked Glc-GalN3 unit, did not lead to the target Trisaccharide backbone. Further O-deacetylation, azido group reduction and debenzylation of the protected Trisaccharide precursor gave the corresponding Trisaccharide amine. The latter structure was used in the synthesis of a series of Trisaccharides bearing an acetyl group, an l -alanine or an N-acetylated l -alanine residue on its amino group at C-2 of GalN.
Nicolai V Bovin - One of the best experts on this subject based on the ideXlab platform.
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block synthesis of a type 2 and b type 2 tetrasaccharides related to the human abo blood group system
Carbohydrate Research, 2016Co-Authors: Ivan M Ryzhov, Elena Korchagina, Inna S Popova, Tatiana V Tyrtysh, Alexander S Paramonov, Nicolai V BovinAbstract:Herein we report the synthesis of 3-aminopropyl glycosides of A (type 2) and B (type 2) tetrasaccharides via [3 + 1] block scheme. Peracetylated trichloroacetimidates of A and B Trisaccharides were used as glycosyl donors. The well-known low reactivity of 4-OH group of N-acetyl-d-glucosamine forced us to test four glucosamine derivatives (3-Bz-1,6-anhydro-GlcNAc and 3-trifluoroacetamidopropyl β-glycosides of 3-Ac-6-Bn-GlcNAc, 3-Ac-6-Bn-GlcN3, and 3-Ac-6-Bn-GlcNAc2) to select the best glycosyl acceptor for the synthesis of type 2 tetrasaccharides. The desired tetrasacchrides were not isolated, when 3-trifluoroacetamidopropyl glycosyde of 3-Ac-6-Bn-GlcNAcβ was glycosylated. Glycosylation of 3-Bz-1,6-anhydro-GlcNAc derivative resulted in α-glycoside as a major product. High stereospecificity was achieved only in the synthesis of B (type 2) tetrasaccharide, when 3-trifluoroacetamidopropyl 3-Ac-6-Bn-GlcNAc2β was applied as the glycosyl acceptor (β/α 5:1), whereas glycosylation with trichloroacetimidate of A Trisaccharide was not stereospecific (β/α 1.3:1). Glycosylation of 3-trifluoroacetamidopropyl glycoside of 3-Ac-6-Bn-GlcN3β with trichloroacetimidates of A and B Trisaccharides provided the same stereochemical yield (β/α 1.5:1).
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design of the blood group ab glycotope
Glycoconjugate Journal, 2005Co-Authors: Elena Korchagina, Anne Imberty, Tatyana V Pochechueva, Polina Obukhova, Andrey A Formanovsky, Robert Rieben, Nicolai V BovinAbstract:Although the nature of the blood groups A and B has been comprehensively studied for a long time, it is still unclear as to what exactly is the epitope that is recognized by antibodies having AB specificity, i.e. monoclonal and polyclonal antibodies which are capable of interacting equally well with the antigens GalNAcalpha 1-3(Fucalpha 1-2)Gal (A Trisaccharide) and Galalpha 1-3(Fucalpha 1-2)Gal (B Trisaccharide), but do not react with their common fragment Fucalpha 1-2Gal. We have supposed that besides Fucalpha 1-2Gal, A and B antigens have one more shared epitope. The Trisaccharides A and B are practically identical from the conformational point of view, the only difference being situated at position 2 of Galalpha residue, i.e. Trisaccharide A has a NHAc group, whereas Trisaccharide B has a hydroxyl group (see formulas). We have hypothesized that the AB-epitope should be situated in the part of the molecule that is opposite to the NHAc group of GalNAc residue. In order to test this hypothesis we have synthesized a polymeric conjugate in such a way that de-N-acetylated A-Trisaccharide is attached to a polymer via the nitrogen in position C-2 of the galactosamine residue. In this conjugate the supposed AB-epitope should be maximally accessible for antibodies from the solution, whereas the discrimination site of antigens A and B by the antibodies should be maximally hidden due to the close proximity of the polymer. Interaction with several anti-AB monoclonal antibodies revealed that a part of them really interacted with the synthetic AB-glycotope, thus confirming our hypothesis. Moreover, similar antibodies were revealed in the blood of healthy blood group 0 donors. Analysis of spatial models was performed in addition to identify the hydroxyl groups of Fuc, Galalpha, and Galbeta residues, which are particularly involved in the composition of the AB-glycotope.
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expression of endogenous lectins galectins receptors for abh epitopes and the mib 1 antigen in esophageal carcinomas and their syntactic structure analysis in relation to post surgical tumor stage and lymph node involvement
Anticancer Research, 2001Co-Authors: Klaus Kayser, Evelyn Hauck, Nicolai V Bovin, Lech Banach, Elzbieta LancasterAbstract:Squamous cell carcinomas of the esophagus, a disease with poor prognosis, are especially frequent in China and South Africa. To initiate the study of endogenous lectins in this tumor class we employed synthetic neoglycoconjugates and focused on galectins as markers. Histological sections of 43 cases of esophageal carcinomas were analyzed with labeled galectins-1 and -3 and their specific antibodies, neoglycoconjugates exposing chemically prepared histo-blood group A-, B- and H-Trisaccharides and the antibody MIB-1 (Ki-67). Features of structural and numerical staining intensities determined quantitatively were correlated to clinical data sets of pTN stages, sex and age of patients. Low tumor stages (pT1/T2) were seen in 10/43 cases (23%) and 65% of the carcinomas surgically treated lacked notable lymph node involvement (pN0). The women were younger than the men (47 years versus 54 years). The proliferation activity of the tumor cells was high and amounted to 75% at average. The presence of galectin-1 and the structural entropy of distribution of staining with carrier-immobilized A-Trisaccharide were associated with pN stages. These initial data indicate that distinct glycohistochemical features appear to have prognostic significance in this tumor class, adding to the emerging significance of this marker class in lung cancer.
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preneoplasia associated expression of calcyclin and of binding sites for synthetic blood group a h Trisaccharide exposing neoglycoconjugates in human lung
Cancer biochemistry biophysics, 1997Co-Authors: K Kayser, Nicolai V Bovin, Sabine Andre, F Y Zeng, H J GabiusAbstract:Development of preneoplastic lesions in human lung is supposed to be accompanied with alterations of distinct biochemical features which might functionally be crucial for this alteration. To contribute to the definition of such determinants in peripheral lung parenchyma, the files of the Department of Pathology, Thoraxklinik, (a total of 2890 cases) were screened for respective tissue specimens. Seventy one cases with complete clinical documentation were found and an age-, sex-, and disease-matched control group was formed. When compared to control group patients, especially the tumor free cases with preneoplastic aberrations revealed a history of exposure to external noxes. Several probes with assumed relevance were tested with the panel of specimens for both groups, focussing on comparative analysis of alveolar lining cells. In addition to labelled neoglycoconjugates which include tissue lectin-seeking probes that expose mono-, di- and blood group-related Trisaccharides, presence of calcium- and annexin-binding calcyclin, of complement component C5b, of the lymphokine macrophage migration inhibitory factor, and of ligands of the serum amyloid P component was evaluated. Compared to normal cells at the alveolar surface in controls, the preneoplastic cells displayed an apparent down-regulation of expression of A/H-Trisaccharide-specific binding sites and an upregulation of expression of calcyclin. These three characteristics correlated with the phenotypic alterations and encourage further studies to elucidate the functional significance of reduced expression of the glycoligand-specific sites and the presence of this member of the S100-family of Ca(2+)-binding proteins.
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selectin receptors 4 synthesis of tetrasaccharides sialyl lewis a and sialyl lewis x containing a spacer group1 2
Journal of Carbohydrate Chemistry, 1996Co-Authors: Nikolay E Nifantev, A.b. Tuzikov, Yury E. Tsvetkov, Alexander S Shashkov, L O Kononov, Vladimir M Menshov, Nicolai V BovinAbstract:ABSTRACT Synthesis of two isomeric tetrasaccharides, namely Neu5Acα(2→3)Galβ(1→3)[Fucα(1→4)GlcNAcβ (sLea) and Neu5Acα(2→3)Galβ(1→4)[Fucα(1→3)]GlcNAcβ (sLex) as 3-aminopropyl glycosides is described. Preparation of these compounds was performed by sialylation of selectively protected Trisaccharides Lea and Lex which contain three unsubstituted OH groups at positions 2, 3 and 4 of Gal residue. Glycosylation of Lex Trisaccharide with ethylthio sialoside under promotion by NIS and TfOH in acetonitrile was effective and regio- and stereoselective to give sLex derivative in 81% yield. In contrast, sialylation of the Lca acceptor was accompanied by a variety of undesirable by-processes, namely. N-thioethylation of the GlcNAc residue, β-sialylation, and lactonisation. In order to improve the yield of sLca tetrasaccharide the glycosylation of Lea acceptor by sialyl donors of ethyl and phenyl thioglycoside (promoted by NIS-TfOH or NBS-Bu4NBr), xanthate (promotion by NIS-TfOH mixture or MeOTf) and phosphite (promote...
Yuji Miyahara - One of the best experts on this subject based on the ideXlab platform.
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specific recognition of human influenza virus with pedot bearing sialic acid terminated Trisaccharides
ACS Applied Materials & Interfaces, 2017Co-Authors: Wenfeng Hai, Tatsuro Goda, Hiroaki Takeuchi, Shoji Yamaoka, Yukichi Horiguchi, Akira Matsumoto, Yuji MiyaharaAbstract:Conducting polymers are good candidates for biosensor applications when molecular recognition element is imparted. We developed Trisaccharide-grafted conducting polymers for label-free detection of the human influenza A virus (H1N1) with high sensitivity and specificity. A 3,4-ethylenedioxythiophene (EDOT) derivative bearing an oxylamine moiety was electrochemically copolymerized with EDOT. The obtained film was characterized by cyclic voltammetry, X-ray photoelectron spectroscopy, scanning electron microscopy, stylus surface profilometer, and AC-impedance spectroscopy. The Trisaccharides comprising Sia-α2,6′-Gal-Glu (2,6-sialyllactose) or Sia-α2,3′-Gal-Glu (2,3-sialyllactose) were covalently introduced to the side chain of the conducting polymers as a ligand for viral recognition. Immobilization of sialyllactose was confirmed by quartz crystal microbalance (QCM) and water contact angle measurements. Specific interaction of 2,6-sialyllactose with hemagglutinin in the envelope of the human influenza A viru...
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Specific Recognition of Human Influenza Virus with PEDOT Bearing Sialic Acid-Terminated Trisaccharides
2017Co-Authors: Wenfeng Hai, Tatsuro Goda, Hiroaki Takeuchi, Shoji Yamaoka, Yukichi Horiguchi, Akira Matsumoto, Yuji MiyaharaAbstract:Conducting polymers are good candidates for biosensor applications when molecular recognition element is imparted. We developed Trisaccharide-grafted conducting polymers for label-free detection of the human influenza A virus (H1N1) with high sensitivity and specificity. A 3,4-ethylenedioxythiophene (EDOT) derivative bearing an oxylamine moiety was electrochemically copolymerized with EDOT. The obtained film was characterized by cyclic voltammetry, X-ray photoelectron spectroscopy, scanning electron microscopy, stylus surface profilometer, and AC-impedance spectroscopy. The Trisaccharides comprising Sia-α2,6′-Gal-Glu (2,6-sialyllactose) or Sia-α2,3′-Gal-Glu (2,3-sialyllactose) were covalently introduced to the side chain of the conducting polymers as a ligand for viral recognition. Immobilization of sialyllactose was confirmed by quartz crystal microbalance (QCM) and water contact angle measurements. Specific interaction of 2,6-sialyllactose with hemagglutinin in the envelope of the human influenza A virus (H1N1) was detected by QCM and potentiometry with enhanced sensitivity by 2 orders of magnitude when compared with that of commercially available kits. The developed conducting polymers possessing specific virus recognition are a good candidate material for wearable monitoring and point-of-care testing because of their processability and mass productivity in combination with printing technologies
Ian M Sims - One of the best experts on this subject based on the ideXlab platform.
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the kinetic analysis of fructan biosynthesis in excised leaves of lolium temulentum l
New Phytologist, 2006Co-Authors: Ian M Sims, R Morgan, Christopher J. PollockAbstract:SUMMARY Excised leaves of Lolium temulentum L. were fed `3C02 at 99 % isotopic abundance in order to study the kinetics of incorporation of photosynthetically fixed carbon into different fructans and to determine the pathways of synthesis between sucrose and high-molecular-weight fructan. Following 6 h exposure to `3C02 of detached and illuminated leaves, analysis of the accumulation of 1-kestose, 6-kestose and neokestose, and of the pattern of labelling observed in these isomers, suggested that they were each formed directly from sucrose at different rates. Similarly, the data suggested that the tetrasaccharide isomers were formed directly from their Trisaccharide precursors. Changes in the concentration of '3C both in the total water-soluble component of the leaves and the fructan pool after 20 h exposure to `3C02 suggested that there was a continual turnover of fructosyl residues. The formation of Trisaccharides from sucrose and subsequent fructosyl transfer to oligo- and polysaccharides of progressively higher molecular weight was consistent with a direct precursor-product relationship. The stable concentration of sucrose observed in leaves between 14 h and 48 h after excision indicated that fructan metabolism in L. temulentum may serve to regulate the sucrose content of the tissue.
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characterization of the enzymatic polymerization of 2 6 linked fructan by leaf extracts from timothy grass phleum pratense
New Phytologist, 1999Co-Authors: Andrew J. Cairns, Mariaangela Machado De Carvalho, Robert J Nash, Ian M SimsAbstract:A fructan polymerase activity was partially purified and concentrated by sequential acid and salt precipitation from extracts of excised, illuminated leaves of timothy grass (Phleum pratense). The polymerase catalysed the de novo synthesis of oligo-and polyfructan from sucrose as sole substrate at near-physiological rates (0.5-0.9 mg g -1 fresh mass h -1 ; 0.9-1.5 nkat g -1 ). Rates of in vitro polymerisation were high, at up to 4.1 mg cm -3 h -1 (7.1 nkat cm -3 ) of total products of degree of polymerization greater than 2 (DP > 2). The Trisaccharides 1-kestose and 6-kestose together with oligosaccharides of up to DP ≤ c. 10 were synthesized in under 2 h at 30°C. In longer incubations, ethanol-precipitable polymers of DP = c. 10-35 (1.6-5.7 kDa) were detected by anion-exchange chromatography and pulsed amperometry. When this polymeric product was used as a primer and re-incubated with fresh enzyme and sucrose, abundant polymers of up to DP = 50 (8.1 kDa) were formed. The structure of the polymeric enzyme product was compared with native fructan from timothy leaves and with standard inulin, using glycosyl-linkage analysis followed by identification of partially methylated alditol acetate derivatives by GC-MS. The deduced structure was a linear (unbranched) 2,6-linked fructose chain terminated with glucose and fructose. The linkage structures of the native and enzyme-generated polymers were identical, increasing confidence in the physiological relevance of the activity. After ultracentrifugation of tissue homogenates at 265 000 g ar , the polymerase remained in the supernatant, demonstrating no tight association with particulate components. The polymerizing reaction was dependent on enzyme concentration, requiring at least 3 g fresh mass equivalent cm 3 (c. 2.7 nkat cm 3 ) for the efficient in vitro generation of fructans of DP > 3. In common with other Trisaccharide-synthesizing and oligofructan-glycosylating enzymes from grasses, the polymerase reaction exhibited both a maximal velocity at pH 5.0-5.5 and a low affinity for sucrose. The polymerization reaction did not saturate fully even at 1.5 M sucrose, and the concentration causing half maximal velocity (apparent K m ) was c. 560 mM. The preparation contained substantial invertase activity (1.8 mg sucrose g -1 fresh mass h -1 = 1.5 nkat g -1 fresh mass) with a K m for sucrose hydrolysis of 5 mM. A single peak of polymerase activity with an M r of 51 kDa was recovered from size-exclusion chromatography (SEC). Invertases of M r 51 and 110 kDa were identified in the preparation. The 110-kDa invertase isoform exhibited no polymerase activity, but synthesized Trisaccharide (mainly 1-kestose) from sucrose. The 51-kDa isoform co-eluted with the polymerase. The Trisaccharide fraction produced by this isoform contained abundant 1-and 6-kestose. After SEC, the purification of the polymerase was 41-fold relative to the original tissue homogenate. The properties of enzymatic polymerization of fructan are discussed with respect to the physiology of accumulation in grass leaves and other systems.
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Fructosyl transfer from sucrose and oligosaccharides during fructan synthesis in excised leaves of Lolium temulentum L.
New Phytologist, 1991Co-Authors: Thomas L. Housley, Ian M Sims, Nicholas C. Carpita, David M. Gibeaut, Christopher J. PollockAbstract:summary Fructan biosynthesis begins with the transfer of a fructosyl moiety from one sucrose molecule to another to yield a Trisaccharide. Trisaccharides may also arise by the reversible transfer of a fructosyl moiety from higher oligomers to sucrose but in this case there is no net fructan synthesis. Short-term and long-term exposure of detached illuminated leaf blades of Lolium temulentum (L.I to 14CO2 was used to examine the mechanism of transfer of fructosyl residues to sucrose. Two Trisaccharides, 1-kestose and neokestose, were found to be radioactive when leaves excised and illuminated for 15 h -were exposed to NCO2 for 30 min. The label increased in neokestose during the chase period, while that in 1-kestose increased for the first 2 h of the chase period then declined for the remaining 4h. With a longer exposure to 14CO2 during the first 6 h of the induction period, three Trisaccharides, neokestose, 1-kestose and 6-kestose were radiolabelled. The label turned over in neokestose and 1-kestose, but continued to accumulate in 6-kestose during a subsequent 18 h chase period. The specific activities of glucose and fructose of the sucrosyl portion and the terminal fructosyl moiety of the various Trisaccharides were compared. In the rapid pulse-chase experiment the specific activity of the1 terminal fructosyl moiety was consistently less than that of the sucrosyl moiety. During the chase period, the specific activity of the terminal and internal fructose moieties became similar. These results indicate that in addition to Trisaccharide formed by transfer of fructosyl units from sucrose, substantial amounts of both neokestose and 1-kestose are made by transfer of fructosyl units from higher oligomers onto sucrose in reactions probably localized in the vacuole.
