Monoclonal antibodies directed against the sugar sequence of lacto-N-fucopentaose III are obtained from mice immunized with human tumors

Four hybridomas obtained from mice immunized with human adenocarcinomas of colon or stomach produce antibodies that bind specifically in solid-phase radioimmunoassay to the ceramide pentasaccharide that contains the lacto-N-fucopentaose III sequence of sugars. Binding of the antibodies to the glycolipid is inhibited by lacto-N-fucopentaose III,

but not by structurally related oligosaccharides. The antibodies bind to glycolipids of erythrocytes, granulocytes, and certain normal and malignant tissues.     

New derivatization and separation procedures for reducing oligosaccharides

4-Trifluoroacetamidoaniline was reacted with reducing oligosaccharides in the presence of sodium cyanoborohydride to give aminoalditol derivatives, useful for linkage to proteins or solid matrices. A mixture of reducing oligosaccharides, difficult to separate by HPLC, was treated in the same way. The resulting derivatives were easily separated by HPLC.Abbreviations TFAN 4-trifluoroacetamidoaniline - LcOse₄ lacto-N-tetraose - IV²Fuc-LcOse₄ lacto-N-fucopentaose l - III⁴Fuc-LcOse₄ lacto-N-fucopentaose II - III³Fuc-nLcOse₄ lacto-N-fucopentaose III - IV²Fuc, III⁴Fuc-LcOse₄ lacto-N-difucohexaose I - II⁶Galß1-4GlcNAc-LcOse₄ lacto-N-hexaose - II³NeuAc-Lac 3-sialyllactose - GlcNAcß1-4GlcNAcß1-4GlcNAc chitotriose - GalNac1-3|Fuc1-2|Galß1-4Glc A-tetrasaccharide     

Distribution of In Vitro Fermentation Ability of Lacto-N-Biose I,a Major Building Block of Human Milk Oligosaccharides,in Bifidobacterial Strains

This study investigated the potential utilization of lacto-N-biose I (LNB) by individual strains of bifidobacteria. LNB is a building block for the human milk oligosaccharides, which have been suggested to be a factor for selective growth of bifidobacteria. A total of 208 strains comprising 10 species and 4 subspecies were analyzed for the presence of the galacto-N-biose/lacto-N-biose I phosphorylase (GLNBP) gene (lnpA) and examined for growth when LNB was used as the sole carbohydrate source. While all strains of Bifidobacterium longum subsp. longum, B. longum subsp. infantis, B. breve, and B. bifidum were able to grow on LNB, none of the strains of B. adolescentis, B. catenulatum, B. dentium, B. angulatum, B. animalis subsp. lactis, and B. thermophilum showed any growth. In addition, some strains of B. pseudocatenulatum, B. animalis subsp. animalis, and B. pseudolongum exhibited the ability to utilize LNB. With the exception for B. pseudocatenulatum, the presence of lnpA coincided with LNB utilization in almost all strains. These results indicate that bifidobacterial species, which are the predominant species found in infant intestines, are potential utilizers of LNB. These findings support the hypothesis that GLNBP plays a key role in the colonization of bifidobacteria in the infant intestine.Bifidobacteria are gram-positive anaerobic bacteria that naturally colonize the human intestinal tract and are believed to be beneficial to human health (21, 30). Breastfeeding has been shown to be associated with an infant fecal microbiota dominated by bifidobacteria, whereas the fecal microbiota of infants who are consuming alternative diets has been described as being mixed and adult-like (12, 21). It has been suggested that the selective growth of bifidobacteria observed in breast-fed newborns is related to the oligosaccharides and other factors that are contained in human milk (human milk oligosaccharides [HMOs]) (3, 4, 10, 11, 16, 17, 34). Kitaoka et al. (15) have recently found that bifidobacteria possess a unique metabolic pathway that is specific for lacto-N-biose I (LNB; Galβ1-3GlcNAc) and galacto-N-biose (GNB; Galβ1-3GalNAc). LNB is a building block for the type 1 HMOs [such as lacto-N-tetraose (Galβ1-3GlcNAcβ1-3Galβ1-4Glc), lacto-N-fucopentaose I (Fucα1-2Galβ1-3GlcNAcβ1-3Galβ1-4Glc), and lacto-N-difucohexaose I (Fucα1-2Galβ1-3[Fucα1-4]GlcNAcβ1-3Galβ1-4Glc)], and GNB is a core structure of the mucin sugar that is present in the human intestine and milk (18, 27). The GNB/LNB pathway, as previously illustrated by Wada et al. (33), involves proteins/enzymes that are required for the uptake and degradation of disaccharides such as the GNB/LNB transporter (29, 32), galacto-N-biose/lacto-N-biose I phosphorylase (GLNBP; LnpA) (15, 24) (renamed from lacto-N-biose phosphorylase after the finding of phosphorylases specific to GNB [23] and LNB [22]), N-acetylhexosamine 1-kinase (NahK) (25), UDP-glucose-hexose 1-phosphate uridylyltransferase (GalT), and UDP-galactose epimerase (GalE). Some bifidobacteria have been demonstrated to be enzymatically equipped to release LNB from HMOs that have a type 1 structure (lacto-N biosidase; LnbB) (33) or GNB from the core 1-type O-glycans in mucin glycoproteins (endo-α-N-acetylgalatosaminidase) (6, 13, 14). It has been suggested that the presence of the LnbB and GNB/LNB pathways in some bifidobacterial strains could provide a nutritional advantage for these organisms, thereby increasing their populations within the ecosystem of these breast-fed newborns (33).The species that predominantly colonize the infant intestine are the bifidobacterial species B. breve, B. longum subsp. infantis, B. longum subsp. longum, and B. bifidum (21, 28). On the other hand, strains of B. adolescentis, B. catenulatum, B. pseudocatenulatum, and B. longum subsp. longum are frequently isolated from the adult intestine (19), and strains of B. animalis subsp. animalis, B. animalis subsp. lactis, B. thermophilum and B. pseudolongum have been shown to naturally colonize the guts of animals (1, 2, 7, 8). However, it is unclear whether there is a relationship between the differential colonization of the bifidobacterial species and the presence of the GNB/LNB pathway. In the present study, we investigated the ability of individual bifidobacterial strains in the in vitro fermentation of LNB and in addition, we also tried to determine whether or not the GLNBP gene (lnpA), which is a key enzyme of the GNB/LNB pathway, was present.     

One-pot enzymatic production of β-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-d-galactose (galacto-N-biose) from sucrose and 2-acetamido-2-deoxy-d-galactose (N-acetylgalactosamine)

β-d-Galactopyranosyl-(1→3)-2-acetamido-2-deoxy-d-galactose (galacto-N-biose, GNB) is an important core structure in functional sugar chains such as T-antigen disaccharide and the core 1 sugar chain in mucin glycoproteins. We successfully developed a one-pot enzymatic production of GNB from sucrose and GalNAc by the concomitant action of four enzymes: sucrose phosphorylase, UDP-glucose-hexose 1-phosphate uridylyltransferase, UDP-glucose 4-epimerase, and galacto-N-biose/lacto-N-biose I phosphorylase in the presence of UDP-glucose and phosphate, by modifying the method of lacto-N-biose I production [Nishimoto, M.; Kitaoka, M., Biosci. Biotechnol. Biochem., 2007, 71, 2101-2104]. The reaction yield of GNB was 88% from GalNAc. GNB was isolated from the reaction mixture by crystallization after yeast treatment to obtain approximately 45 g of GNB in 95% purity from a 280-mL reaction mixture.     

Chemical structures of oligosaccharides in milk of the raccoon (<Emphasis Type="Italic">Procyon lotor</Emphasis>)

In this study on milk saccharides of the raccoon (Procyonidae: Carnivora), free lactose was found to be a minor constituent among a variety of neutral and acidic oligosaccharides, which predominated over lactose. The milk oligosaccharides were isolated from the carbohydrate fractions of each of four samples of raccoon milk and their chemical structures determined by ¹H-NMR and MALDI-TOF mass spectroscopies. The structures of the four neutral milk oligosaccharides were Fuc(α1–2)Gal(β1–4)Glc (2′-fucosyllactose), Fuc(α1–2)Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (lacto-N-fucopentaose IV), Fuc(α1–2)Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (fucosyl para lacto-N-neohexaose) and Fuc(α1–2)Gal(β1–4)GlcNAc(β1–3)[Fuc(α1–2)Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (difucosyl lacto-N-neohexaose). No type I oligosaccharides, which contain Gal(β1–3)GlcNAc units, were detected, but type 2 saccharides, which contain Gal(β1–4)GlcNAc units were present. The monosaccharide compositions of two of the acidic oligosaccharides were [Neu5Ac]₁[Hex]₆[HexNAc]₄[deoxy Hex]₂, while those of another two were [Neu5Ac]₁[Hex]₈[HexNAc]₆[deoxy Hex]_3. These acidic oligosaccharides contained α(2–3) or α(2–6) linked Neu5Ac, non reducing α(1–2) linked Fuc, poly N-acetyllactosamine (Gal(β1–4)GlcNAc) and reducing lactose.     

Aporphine alkaloids and cytotoxic lignans from the roots of Illigera luzonensis

Six aporphine alkaloids, (+)-(S)-N-butyrylcaaverine (1), (+)-(S)-N-propionylcaaverine (2), (+)-(S)-N-acetylcaaverine (3), (+)-(6aR,7R)-N-butyrylnorushinsunine (4), (+)-(6aR,7R,E)-N-(but-2-enoyl)norushinsunine (5), and N-formyldehydrocaaverine (6) were isolated from the roots of Illigera luzonensis, together with 16 known compounds. Their structures were determined through spectroscopic and MS analyses. Among the isolates, (−)-deoxypodophyllotoxin (13) was the most cytotoxic, with IC₅₀ values of 0.0057, 0.0067, 0.00004, and 0.0035 μg/mL, respectively, against DLD-1, CCRF-CEM, HL-60, and IMR-32 cell lines. In addition, (−)-yatein (12) exhibited cytotoxic effects, with IC₅₀ values of 0.81, 0.20, and 0.59 μg/mL, respectively, against DLD-1, CCRF-CEM, and HL-60 cell lines.     

Oxygenated verticillene derivatives from Bursera suntui

Medium polarity fractions of the hexane extracts of the stems of Bursera suntui afforded six previously known (1-6) and four hitherto unknown verticillane derivatives: (1S,3Z,7S,8S,11S,12S)-(+)-7,8-epoxyverticill-3-en-12,20-diol (7), (1S,3Z,7S,8S,11S,12S)-(+)-7,8-epoxyverticill-3-en-12,20-diol 20-acetate (8), (1S,3Z,7S,11S,12S)-(+)-verticilla-3,8(19)-dien-7,12,20-triol (9), and (1S,3Z,7S,11S,12S)-(+)-verticilla-3,8(19)-dien-7,12,20-triol 20-acetate (10). Acetylation of 9 and 10 yielded (1S,3Z,7S,11S,12S)-(+)-verticilla-3,8(19)-dien-7,12,20-triol 7,20-diacetate (11), while hydrolysis of 8 gave 7. The structures and stereochemistry of 7-11 were established by spectroscopic analyses, particularly by 1D and 2D NMR spectra and HRESIMS. The conformational preferences of 7-11 were studied by molecular mechanics modelling employing the Monte Carlo protocol followed by B3LYP/DGDZVP DFT calculation, thus supporting the observed ¹H NMR NOESY cross peaks.     

Characterization of the sugar-binding specificity of the toxic lectins isolated from Abrus pulchellus seeds

The sugar-binding specificity of the toxic lectins from Abrus pulchellus seeds was investigated by combination of affinity chromatography of glycopeptides and oligosaccharides of well-defined structures on a lectin-Sepharose column and measurement of the kinetic interactions in real time towards immobilized glycoproteins. The lectins showed strong affinity for a series of bi- and triantennary N-acetyllactosamine type glycans. The related asialo-oligosaccharides interact more strongly with the lectins. The best recognized structures were asialo-glycopeptides from fetuin. Accordingly, the kinetic interaction with immobilized asialofetuin was by far the most pronounced. Human and bovine lactotransferrins and human serotransferrin interacted to a lesser extent. The interaction with asialofetuin was inhibited by galactose in a dose dependent manner. Lactose, N-acetyllactosamine and lacto-N-biose exhibited similar degree of inhibition while N-acetylgalactosamine was a poor inhibitor. These results suggested that the carbohydrate-binding site of the Abrus pulchellus lectins was specific for galactose and possess a remarkable affinity for the sequences lactose [-D-Gal-(14)-D-Glc], N-acetyllactosamine [-D-Gal-(14)-D-GlcNAc] and lacto-N-biose [-D-Gal-(13)-D-GlcNAc].     

An investigation of Cu(II) and Ni(II)-catalysed hydrolysis of (di)imines

The reactions of six diimine ligands with Cu(II) and Ni(II) halide salts have been investigated. The diimine ligands were Ph₂CN(CH₂)_nNCPh₂ (n = 2 (Bz₂en, 1a), 3 (Bz₂pn, 1b), 4 (Bz₂bn, 1c)), N,N′-bis-(2-tert-butylthio-1-ylmethylenebenzene)-2,2′diamino-biphenyl (2), N,N′-bis-(2-chloro-1-ylmethylenebenzene)-1,3-diaminobenzene (3) and N,N′-bis-(2-chloro-1-ylmethylenebenzene)-1,2-ethanediamine (4). Reactions of 1a-c, 2-4 with CuCl₂·2H₂O in dry ethanol at ambient temperature led to complete or partial hydrolysis of the diimine ligands to ultimately form copper diamine complexes. The non-hydrolyzed complexes of 1b and 1c, [Cu(L)Cl₂] (L = 1b, 1c), could be isolated when the reactions were carried out at low temperatures, and the half-hydrolyzed complex [Cu(Bzpn)Cl₂] could also be identified via X-ray crystallography. Similarly, reactions of 1a or 1b with NiCl₂·6H₂O or [NiBr₂(dme)] led to rapid hydrolysis of the imines and Ni complexes containing half-hydrolyzed 1a (Bzen; [trans-[Ni(Bzen)₂Br₂]) and 1b (Bzpn; [Ni(Bzpn)Br₂] could be isolated and identified via single crystal X-ray analysis. Kinetic studies were made of the hydrolyses of 1a, 1b in THF and 2 in acetone, in the presence of Cu(II), and of 1a in acetonitrile, in the presence of Ni(II). Activation parameters were determined for the latter reaction and for the copper-catalyzed hydrolysis of 2; the relatively large negative activation entropies clearly indicate rate-determining steps of an associative nature.     

Characterization of Three ��-Galactoside Phosphorylases from Clostridium phytofermentans: DISCOVERY OF d-GALACTOSYL-��1��4-l-RHAMNOSE PHOSPHORYLASE*

We characterized three d-galactosyl-β1→3-N-acetyl-d-hexosamine phosphorylase (EC 2.4.1.211) homologs from Clostridium phytofermentans (Cphy0577, Cphy1920, and Cphy3030 proteins). Cphy0577 and Cphy3030 proteins exhibited similar activity on galacto-N-biose (GNB; d-Gal-β1→3-d-GalNAc) and lacto-N-biose I (LNB; d-Gal-β1→3-d-GlcNAc), thus indicating that they are d-galactosyl-β1→3-N-acetyl-d-hexosamine phosphorylases, subclassified as GNB/LNB phosphorylase. In contrast, Cphy1920 protein phosphorolyzed neither GNB nor LNB. It showed the highest activity with l-rhamnose as the acceptor in the reverse reaction using α-d-galactose 1-phosphate as the donor. The reaction product was d-galactosyl-β1→4-l-rhamnose. The enzyme also showed activity on l-mannose, l-lyxose, d-glucose, 2-deoxy-d-glucose, and d-galactose in this order. When d-glucose derivatives were used as acceptors, reaction products were β-1,3-galactosides. Kinetic parameters of phosphorolytic activity on d-galactosyl-β1→4-l-rhamnose were k_cat = 45 s⁻¹ and K_m = 7.9 mm, thus indicating that these values are common among other phosphorylases. We propose d-galactosyl-β1→4-l-rhamnose phosphorylase as the name for Cphy1920 protein.Phosphorylases are a group of enzymes involved in formation and cleavage of glycoside linkage together with glycoside hydrolases and glycosyl-nucleotide glycosyltransferases (synthases). Phosphorylases, which reversibly phosphorolyze oligosaccharides to produce monosaccharide 1-phosphate, are generally intracellular enzymes showing strict substrate specificity. Physiologically, such strict substrate specificity is considered to be closely related to the environment containing bacteria possessing them. For example, d-galactosyl-β1→3-N-acetyl-d-hexosamine phosphorylase (GalHexNAcP²; EC 2.4.1.211) from Bifidobacterium longum, an intestinal bacterium, forms part of the pathway metabolizing galacto-N-biose (GNB; d-Gal-β1→3-d-GalNAc) from mucin and lacto-N-biose I (LNB; d-Gal-β1→3-d-GlcNAc) from human milk oligosaccharides, both of which are present in the intestinal environment, with GNB- and LNB-releasing enzymes and GNB/LNB transporter (1–8). Another example is cellobiose phosphorylase from Cellvibrio gilvus, which is a cellulolytic bacterium. Cellobiose phosphorylase forms an important cellulose metabolic pathway with an extracellular cellulase system producing cellobiose (9, 10).The reversible catalytic reaction of phosphorylases is one of the most remarkable features that make them suitable catalysts for practical syntheses of oligosaccharides. An oligosaccharide can be produced from inexpensive material by combining reactions of two phosphorylases, one for phosphorolyzing the material and the other for synthesizing the oligosaccharide, in one pot. Based on this idea, LNB is synthesized on a large (kg) scale using sucrose phosphorylase and GalHexNAcP (11). Practical synthesis methods of trehalose and cellobiose have also been developed (12, 13). However, only 14 kinds of substrate specificities have been reported among phosphorylases (13), thus restricting their use. Therefore, it would be useful to find a phosphorylase with novel activity.GalHexNAcP phosphorolyzes GNB and LNB to produce α-d-galactose 1-phosphate (Gal 1-P) and the corresponding N-acetyl-d-hexosamine. To date, GalHexNAcP is the only phosphorylase known to act on β-galactoside. This enzyme was first found in the cell-free extract of Bifidobacterium bifidum (14) and then in B. longum (1, 15), Clostridium perfringens (16), Propionibacterium acnes (17), and Vibrio vulnificus (18). These studies revealed that GalHexNAcPs were classified into three subgroups based on substrate preference between GNB and LNB. These subgroups are as follows: 1) galacto-N-biose/lacto-N-biose I phosphorylase (GLNBP), showing similar activity on both GNB and LNB (B. longum and B. bifidum); 2) galacto-N-biose phosphorylase (GNBP), preferring GNB to LNB (C. perfringens and P. acnes); and 3) lacto-N-biose I phosphorylase (LNBP), preferring LNB to GNB (V. vulnificus) (18). The ternary structure of GLNBP from B. longum (GLNBP_Bl) has been revealed recently (19). Based on the similarity in ternary structures between GLNBP_Bl and β-galactosidase from Thermus thermophilus, which belongs to glycoside hydrolase family 42 (19, 20), GalHexNAcP homologs are classified as GH112 (glycoside hydrolase family 112), although phosphorylases are glycosyltransferases (21, 22).Clostridium phytofermentans is an anaerobic cellulolytic bacterium. It is found in soil and grows optimally at 37 °C (23). Its whole genome sequence has been revealed (GenBank^TM accession number {"type":"entrez-nucleotide","attrs":{"text":"CP000885","term_id":"160426828","term_text":"CP000885"}}CP000885). The bacterium possesses three GalHexNAcP homologous genes (cphy0577, cphy1920, and cphy3030 genes; GenBank^TM accession numbers are {"type":"entrez-protein","attrs":{"text":"ABX40964.1","term_id":"160427401","term_text":"ABX40964.1"}}ABX40964.1, {"type":"entrez-protein","attrs":{"text":"ABX42289.1","term_id":"160428726","term_text":"ABX42289.1"}}ABX42289.1, and {"type":"entrez-protein","attrs":{"text":"ABX43387.1","term_id":"160429824","term_text":"ABX43387.1"}}ABX43387.1, respectively). C. phytofermentans has the ability to utilize a wide range of plant polysaccharides (23), and substrate specificities of these three gene products (Cphy0577, Cphy1920, and Cphy3030 proteins) are considered to be responsible for this ability. Furthermore, the three proteins have not been clearly categorized as GLNBP, GNBP, or LNBP, based on the phylogenetic tree shown in Fig. 1.Open in a separate windowFIGURE 1.Phylogenetic tree of GalHexNAcP homologs in GH112. Multiple alignment was performed using ClustalW2 (available on the World Wide Web). A phylogenetic tree was constructed using Treeview version 1.6.6. The proteins characterized in this study are represented with boldface letters in boxes with a heavy outline. The other proteins are numbered serially in boxes. Characterized GLNBP, GNBP, and LNBP are represented with boldface black letters on a gray background, boldface white letters on a gray background, and boldface white letters on a black background, respectively. Organisms and GenBank^TM accession numbers of numbered proteins are as follows: 1, CPF0553 (C. perfringens ATCC13124, {"type":"entrez-protein","attrs":{"text":"ABG83511.1","term_id":"110674524","term_text":"ABG83511.1"}}ABG83511.1) (16); 2, CPE0573 (C. perfringens str.13, {"type":"entrez-protein","attrs":{"text":"BAB80279.1","term_id":"18144232","term_text":"BAB80279.1"}}BAB80279.1); 3, CPR0537 (C. perfringens SM101, {"type":"entrez-protein","attrs":{"text":"ABG86710.1","term_id":"110683340","term_text":"ABG86710.1"}}ABG86710.1); 4, LnpA2 (B. bifidum JCM1254, {"type":"entrez-protein","attrs":{"text":"BAE95374.1","term_id":"107597820","term_text":"BAE95374.1"}}BAE95374.1) (14, 15); 5, LnpA1 (B. bifidum JCM1254, {"type":"entrez-protein","attrs":{"text":"BAD80752.1","term_id":"56676017","term_text":"BAD80752.1"}}BAD80752.1) (14, 15); 6, GLNBP_Bl (B. longum subsp. longum JCM 1217, {"type":"entrez-protein","attrs":{"text":"BAD80751.1","term_id":"56676015","term_text":"BAD80751.1"}}BAD80751.1) (1, 16); 7, Blon_2174 (B. longum subsp. infantis ATCC 15697, {"type":"entrez-protein","attrs":{"text":"ACJ53235.1","term_id":"213524488","term_text":"ACJ53235.1"}}ACJ53235.1); 8, BL1641 (B. longum NCC2705, {"type":"entrez-protein","attrs":{"text":"AAN25428.1","term_id":"23326930","term_text":"AAN25428.1"}}AAN25428.1); 9, BLD_1765 (B. longum DJO10A, {"type":"entrez-protein","attrs":{"text":"ACD99210.1","term_id":"189429062","term_text":"ACD99210.1"}}ACD99210.1); 10, GnpA (P. acnes JCM6473, {"type":"entrez-nucleotide","attrs":{"text":"AB468065","term_id":"219807264","term_text":"AB468065"}}AB468065) (17); 11, GnpA (P. acnes JCM6425, {"type":"entrez-nucleotide","attrs":{"text":"AB468066","term_id":"219807262","term_text":"AB468066"}}AB468066) (17); 12, PPA0083 (P. acnes KPA171202, {"type":"entrez-protein","attrs":{"text":"AAT81843.1","term_id":"50839176","term_text":"AAT81843.1"}}AAT81843.1); 13, VV2_1091 (V. vulnificus CMCP6, {"type":"entrez-protein","attrs":{"text":"AAO07997.1","term_id":"27359049","term_text":"AAO07997.1"}}AAO07997.1) (18); 14, VVA1614 (V. vulnificus YJ016, {"type":"entrez-protein","attrs":{"text":"BAC97640.1","term_id":"37201820","term_text":"BAC97640.1"}}BAC97640.1); 15, Oter_1377 (Opitutus terrae PB90-1, {"type":"entrez-protein","attrs":{"text":"ACB74662.1","term_id":"177840410","term_text":"ACB74662.1"}}ACB74662.1); 16, BCQ_1989 (B. cereus Q1, {"type":"entrez-protein","attrs":{"text":"ACM12417.1","term_id":"221239707","term_text":"ACM12417.1"}}ACM12417.1); 17, BCAH187_A2105 (Bacillus cereus AH187, {"type":"entrez-protein","attrs":{"text":"ACJ78918.1","term_id":"217064668","term_text":"ACJ78918.1"}}ACJ78918.1).In this study, we characterized the three proteins. We reported that two of them were GalHexNAcPs and that the other was a β-galactoside phosphorylase showing unique substrate specificity.     

Identification of N-Acetylhexosamine 1-Kinase in the Complete Lacto-N-Biose I/Galacto-N-Biose Metabolic Pathway in Bifidobacterium longum

We have determined the functions of the enzymes encoded by the lnpB, lnpC, and lnpD genes, located downstream of the lacto-N-biose phosphorylase gene (lnpA), in Bifidobacterium longum JCM1217. The lnpB gene encodes a novel kinase, N-acetylhexosamine 1-kinase, which produces N-acetylhexosamine 1-phosphate; the lnpC gene encodes UDP-glucose hexose 1-phosphate uridylyltransferase, which is also active on N-acetylhexosamine 1-phosphate; and the lnpD gene encodes a UDP-glucose 4-epimerase, which is active on both UDP-galactose and UDP-N-acetylgalactosamine. These results suggest that the gene operon lnpABCD encodes a previously undescribed lacto-N-biose I/galacto-N-biose metabolic pathway that is involved in the intestinal colonization of bifidobacteria and that utilizes lacto-N-biose I from human milk oligosaccharides or galacto-N-biose from mucin sugars.     

Thermochemistry of N-C bonds hydrolysis in amides,peptides, N-acetyl amino acids and high-energy N-C bonds hydrolysis in N-acetyl imidazole and urea

• 1.1. The reaction enthalpies of hydrolysis of amides, peptides and N-acetyl amino acids were calculated for both ionized and un-ionized forms of reaction components.
• 2.2. The average values of reaction enthalpies of amides, peptides and N-acetyl amino acids hydrolysis were essentially different from each other for ionized forms of reaction components and were equal for un-ionized forms of reaction components in the error interval.
• 3.3. As an example of high-energy N-C bonds N-acetyl imidazol and urea were discussed. It was found that the reaction enthalpies of hydrolysis of above compounds were different from analogous thermodynamic values of hydrolysis of amides, peptides and N-acetyl amino acids for any forms of components.

     

Glycolytic activity of enzyme preparation from the red king crab (<Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis>) hepatopancreas

Enzyme preparation exhibiting glycolytic activity yielding chitooligosaccharides along with N-acetyl-D-glucosamine was obtained from the red king crab (Paralithodes camtschaticus) hepatopancreas. The results of the analysis confirmed the presence of endo- and exochitinase activities in the preparation. HPLC showed that the hydrolysis products of chitin and chitosan did not contain D(+)-glucosamine, which is indicative of the absence of deacetylase and, apparently, exochitosanase activities. A comparison of the dependence of the enzyme preparation activity on temperature and pH of the incubation medium suggests that chitinase and protease activities are exhibited by different enzymes.     

Facile route for the synthesis of the iminosugar nucleoside (3R,4R)-1-(pyren-1-yl)-4-(hydroxymethyl)pyrrolidin-3-ol

N-(Pyren-1-yl)-(3R,4S)-4-[(1S,2R)-1,2,3-trihydroxypropyl]pyrrolidin-3-ol (4) was obtained in 36% yield from 3-deoxy-3-C-formyl-1,2:5,6-di-O-isopropylidene-α-d-allofuranose (3) by combined hydrolysis and aminoalkylation reactions with 1-aminopyrene in a one-pot reaction. Cleavage reactions of the exocyclic triol chain in 4 with NaIO₄ and NaBH₄ resulted in iminosugars 7 and 8, which are analogues of the furanose forms of 2-deoxy-d-allose and of 2-deoxy-d-ribose, the latter analogue N-(pyren-1-yl)-(3R,4R)-4-(hydroxymethyl)pyrrolidin-3-ol (8) being formed in 83% yield.     

Construction of 1-2D Cu(or Cu) metal-organic architectures with metal thiocyanates and bipyridyl spacers: Syntheses, structures, and thermal properties

Three new coordination polymers based on IB metal thiocyanates, [Cu^II(NCS)₂(DMSO)₄(meso-dpb)]_n (1), (2), [Cu^I(NCS)(pia)]_n (3) (dpb = 2,3-di(4-pyridyl)-2,3-butanediol, bpp = 1,3-bis(4-pyridyl)propane, pia = N,N′-(1,2-phenylene)diisonicotinamide), have been synthesized by the pre-assembly method and characterized by X-ray crystallography. In 1, Cu^II cations are bridged by meso-dpb ligands to form a one-dimensional (1D) linear chain. Compound 2 consists of 2D undulated layers of (4, 4) topology that show twofold parallel interpenetration. In the case of 3, the M^I center adopts tetrahedral coordination geometry and the 2D networks are formed by organic ligand with “folding ruler-shaped” NCS⁻-M chains. The thermal properties of 1-3 were also investigated.