Glycosylation

Khóa luận được nghiên cứu với mục tiêu nhằm nghiên cứu dịch tễ học, lâm sàng, cận lâm sàng ở trẻ bị viêm mao mạch dị ứng. Đánh giá bước đầu kết quả điều trị trẻ bị viêm mao mạch dị ứng tại khoa Nhi, bệnh viện Bạch Mai.

69p chuheodethuong25 12-07-2021 50 10   Download

Luận án thực hiện nghiên cứu với mục đích tạo ra những hợp chất mới có hoạt tính sinh học, chúng tôi đã tiến hành tổng hợp các hợp chất thiosemicarbazon trên cơ sở phản ứng ngưng tụ các hợp chất carbonyl của coumarin với các glycosyl thiosemicarbazid và bước đầu thăm dò khả năng chuyển hóa đóng vòng cũng như hoạt tính sinh học của chúng. Mời các bạn cùng tham khảo.

27p longnguyentran000 23-12-2016 68 1   Download

The present work reports isolation and characterization of a highly glycosylated protein from bovine milk fat globule membranes, known as PAS III. Partial amino-acid sequencing of the purified protein allowed construction of degenerate oligonucleotide primers, enabling isolation of a full-length cDNA encoding a protein of 330 amino-acid residues. N-terminal amino-acid sequencing of derived peptides and the purified protein confirmed 76% of the sequence and demonstrated presence of a cleavable signal peptide of 23 residues, leaving a mature protein of 307 amino acids.

9p system191 01-06-2013 50 4   Download

Med. Zentrum fur Hygiene und Medizinische Mikrobiologie, Philipps-Universitat Marburg, Marburg, Germany Mannose analogues (2-deoxy-D -glucose, 2-deoxy-2-fluoroD -glucose and 2-amino-2-deoxy-D -mannose) have been used to study glycosylphosphatidylinositol (GPtdIns) biosynthesis and GPtdIns protein anchoring in protozoal and mammalian systems. The effects of these analogues on GPtdIns biosynthesis and GPtdIns-protein anchoring of the human malaria parasite Plasmodium falciparum were evaluated in this study. ...

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Strictosidine glucosidase (SG) is an enzyme that catalyses the second step in the biosynthesis of various classes of monoterpenoid indole alkaloids. Based on the comparison of cDNA sequences of SG from Catharanthus roseus and raucaffricine glucosidase (RG) from Rauvolfia serpentina, primers for RT-PCR were designed and the cDNA encoding SG was cloned from R. serpentina cell suspension cultures. The active enzyme was expressed in Escherichia coli and purified to homogeneity. Analysis of its deduced amino-acid sequence assigned the SG from R. serpentina to family 1 of glycosyl hydrolases.

10p research12 01-06-2013 43 5   Download

We have characterized a glycosylated, 31 amino-acid peptide of 4932 Da isolated from Drosophila melanogaster males. The mature peptide contains a sugar moiety of 1184 Da at a NDT consensus glycosylation site and a disulfide bond. It is synthesized in the male ejaculatory duct via a 54 amino-acid precursor containing an N-terminal signal peptide and Arg-Lys at the C-terminus which is cleaved off during maturation. The gene contains an intron of 53 bp and is localized in the cytological region 99B of the D. melanogaster genome....

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The structure of post-translational modifications of human heparin cofactor II isolated from human serum and from recombinant Chinese hamster ovary cells and their effects on heparin binding have been characterized. Oligosaccharide chains were found attached to all three potential N-glycosylation sites in both protein preparations. The carbohydrate structures of heparin cofactor II circulating in blood are complex-type diantennary and triantennary chains in a ratio of 6 : 1 with the galactose being 90% sialylated with a2 fi 6 linked N-acetylneuraminic acid....

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Glycosylatedpolyenemacrolide antibiotics, as nystatins and amphotericins, are amphiphilic structures known to exert antifungal activity by disrupting the fungal cell membrane, leading to leakage of cellular materials, and cell death. This membrane disruption is strongly influenced by the presence and the exact nature of the membrane sterols.

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Human butyrylcholinesterase (BChE; EC 3.1.1.8) is of particular interest because it hydrolyzes or scavenges a wide range of toxic compounds including cocaine, organophos-phorus pesticides andnerveagents.The relative contribution of each N-linked glycan for the solubility, the stability and the secretionof the enzymewas investigated. Arecombinant monomeric BChE lacking four out of nine N-glycosylation sites and the C-terminal oligomerization domain was stably expressed as a monomer in CHO cells.

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O-Glycosylation of three consecutive Thr residues in a fluorescein-conjugated peptide PTTTPLK)which mimics a portion of mucin 2)by four isozymes of UDP-N-ace-tylgalactosaminyltransferases (pp-GalNAc-T1, T2, T3, or T4) was investigated. Partially glycosylated versions of this peptide, PT*TTPLK, PTTT*PLK, PT*TT*PLK, PTT*T*PLK, PT*
TTPLK, andPTTT*
PLK(*,N-acetyl-galactosamine;
, galactose), were also tested.

11p tumor12 22-04-2013 30 3   Download

Bothrops snake venoms are known to induce local tissue damage suchas hemorrhage andmyonecrosis. Theopossum Didelphis marsupialisis resistant to these snake venoms and has natural venom inhibitors in its plasma. The aim of this work was to clone and study the chemical, physicochemical andbiological properties ofDM64, an antimyotoxic protein from opossum serum. DM64 is an acidic protein showing 15% glycosylation andwith amolecular mass of 63 659 Da when analysed by MALDI-TOF MS.

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The heat-stable enterotoxin peptides (ST) produced by enterotoxigenicEscherichia coliare one of the major causes of transitory diarrhea in the developing world. Toxin bind-ing to its receptor, guanylyl cyclase C (GC-C), results in receptor activation and the production of high intracellular levels of cGMP. GC-C is expressed in two differentially glycosylated forms in intestinal epithelial cells. Prolonged exposure of human colonic cell lines to ST peptides induces cellular refractoriness to the ST peptide, in terms of intra-cellular cGMP accumulation....

10p tumor12 20-04-2013 38 3   Download

We have compared the site-by-siteN-glycosylation status of human lactoferrin (Lf) produced in maize, a monocotyle-don, and in tobacco, usedas amodel dicotyledon.Maizeand tobacco plants were stably transformed and recombinant Lf was purified from both seeds and leaves. N-glycopeptides were generated by trypsin digestion of recombinant Lf and purified by reverse-phase HPLC. The N-glycosylation pat-tern of each site was determined by mass spectrometry. Our results indicated that the N-glycosylation patterns of recombinant Lf produced in maize and tobacco share common structural features....

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Until now, only a small amount of information is available about tomato allergens. In the present study, a glycosylated allergen of tomato (Lycopersicon esculentum), Lyc e 2, was purified from tomato extract by a two-step FPLC method. The cDNA of two different isoforms of the protein, Lyc e 2.01 and Lyc e 2.02, was cloned into the bacterial expressionvector pET100D. The recombinant proteinswere purified by electroelution and refolded.

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The plant enzyme arbutin synthase isolated from cell sus-pension cultures ofRauvolfia serpentinaand heterologously expressed inEscherichia coliis a member of the NRD1b family of glycosyltransferases. This enzyme was used to prove, by site-directed mutagenesis, suggested catalytic domains and reaction mechanisms proposed for enzyme-catalyzed glycosylation. Replacement of amino acids far from the NRD domain do not significantly affect arbutin synthase activity.

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In addition to the major carbohydrate moieties of the glycosylphosphatidylinositol (GPI) anchor, we report that Plasmodiumfalciparummerozoite surface protein1 (MSP-1) bearsO-GlcNAc modifications predominantly in b-ano-meric configuration, in both the C- andN-terminal portions of the protein. Subcellular fractionation of parasitized erythrocytes in the late trophozoite/schizont stage reveals that GPI-anchored C-terminal fragments of MSP-1 are recovered in Triton X-100 resistant, low-density membrane fractions....

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Sequence analysis of aPaenibacillussp. BP-23 recombinant clone coding for a previously described endoglucanase revealed the presence of an additional truncated ORF with homology to family 48 glycosyl hydrolases. The corres-ponding 3509-bp DNA fragment was isolated after gene walking and cloned inEscherichia coliXl1-Blue for expres-sion and purification. The encoded enzyme, a cellulase of 1091 amino acids with a deduced molecular mass of 118 kDa and a pI of 4.

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The heat- and pressure-induced unfolding of the glycosyl-ated and unglycosylated forms of mature carboxypeptidase Y and the precursor procarboxypeptidase Y were analysed by differential scanning calorimetry and/or by their intrinsic fluorescence in the temperature range of 20–75
Corthe pressure range of 0.1–700 MPa. Under all conditions, the precursor form showed a clear two-state transition from a folded to an unfolded state, regardless of the presence of the carbohydrate moiety.

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Saccharomyces cerevisiaeGpi3p is the UDP-GlcNAc-bind-ing andpresumed catalytic subunit of the enzyme that forms GlcNAc-phosphatidylinositol in glycosylphosphatidylinosi-tol biosynthesis. It is anessential proteinwithanEX7 Emotif that is conserved in four families of retaining glycosyl-transferases. All Gpi3ps contain a cysteine residue four residues C-terminal to EX7E. To test their importance for Gpi3p functionin vivo,Glu289 and297 in theEX7 Emotif of S.

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Mucin type O-glycosylation is a widespread modification of eukaryotic pro-teins. The transfer of N-acetylgalactosamine to selected serine or threonine residues is catalyzed by a family of polypeptide N-acetylgalactosaminyl-transferases localized in the Golgi apparatus. The most abundant elonga-tion of O-glycans is the addition of a b1-3 linked galactose by the core-1 b1-3 galactosyltransferase (core-1b3GalT), thereby building the T-antigen or core-1 structure Gal(b1-3)GalNAc(a1-O).

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