共查询到20条相似文献,搜索用时 31 毫秒
1.
Boel Lanne Jeana Cîopraga Jörgen Bergström Cecilia Motas Karl-Anders Karlsson 《Glycoconjugate journal》1994,11(4):292-298
The carbohydrate-binding specificity ofPseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal3Gal- or Gal4Gal-structures.Abbreviations PA-I
Pseudomonas aeruginosa lectin I
- Cer
ceramide
- lactosylceramide
Gal4GlcCer
- iso globotriaosylcerami
Gal3Gal4GlcCer
- globotriaosylceramide
Gal4Gal4GlcCer
- globoside or globotetraosylceramide
GalNAc3Gal4Gal4GlcCer
- Forssman glycolipid
GalNAc3GalNAc3Gal4Gal4GlcCer
- P1 glycolipid
Gal4Gal4GlcNAc3Gal4GlcCer
- lactoneotetraosylceramide
Gal4GlcNAc3Gal4GlcCer
- B5 glycolipid
Gal3Gal4GlcNAc3Gal4GlcCer
- gangliotetraosylceramide
Gal3GalNAc4Gal4GlcCer
- GM1
Gal3GalNAc4(NeuAc3)Gal4GlcCer
- RBC
red blood cells
- BSA
bovine serum albumin
- PBS
phosphate-buffered saline
- SDS
sodium dodecyl sulfate
- TLC
thin-layer chromatography
- HPLC
high pressure liquid chromatography
- MS
mass spectrometry
- FAB
fast-atom bombardment
- EI
electron impact 相似文献
2.
Elizabeth A. Bray Satoshi Naito Nai-Sui Pan Edwin Anderson Philip Dubé Roger N. Beachy 《Planta》1987,172(3):364-370
Soybean (Glycine max (L.) Merr.) seeds contain the storage protein -conglycinin, encoded by a multigene family. -Conglycinin consists of three subunits; , , and . A genomic clone for a -subunit of -conglycinin has been characterized by restriction-enzyme mapping and hybrid selected in-vitro translation followed by immunoprecipitation. In order to determine the developmental regulation of this -subunit gene, its expression was studied in seeds of transgenic petunia (Petunia hybrida) and tobacco (Nicotiana tabacum L.) plants. The -subunit expressed in seeds of petunia and tobacco was recognized by anti--conglycinin serum at a relative molecular mass of 53 000, equivalent to that of the native protein. Separation of the petunia-seed proteins by isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis showed that multiple isoelectric forms of the -subunit were produced. There was approximately a twofold variation in the accumulation of the -subunit protein in the mature seeds of transgenic petunia plants, each containing a single -subunit gene. However, the level of protein accumulation in mature seeds and the amount of -subunit mRNA in developing seeds was not correlated. Accumulation of the -subunit protein in transgenic seeds was less than the -subunit protein that accumulated in transgenic petunia seeds containing a single -subunit gene and less than the amount of the -subunit in mature soybean seeds which contain 8–13 -subunit genes. In transgenic tobacco plants, the accumulation of the -subunit protein in seeds was generally well correlated with the number of genes that were incorporated in the different transformants.Abbreviations kb
kilobase
- kDa
kilodalton
- Mr
relative molecular mass
- SDS-PAGE
sodium dodecyl sulfate polyacrylamide gel electrophoresis 相似文献
3.
Summary Two double heterozygous 0/0 thalassemic sibs of Mexican descent were studied. The father had a 0/0 genotype, while the mother, one sib and several maternal relatives were 0/0 heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both 0 and 0 genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between 0 and genes followed by a crossing-over which would results in a 0 recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed. 相似文献
4.
Our recent studies have revealed the existence of two distinct Gal: 3-O-sulfotransferases capable of acting on the C-3 position of galactose in a Core 2 branched structure, e.g., Gal14GlcNAc16(Gal13)GalNac1OBenzyl as acceptor to give 3-O-sulfoGal14GlcNAc13(Gal13)GalNAc1OB 20 and Gal14GlcNAc16(3-O-sulfoGal13)GalNAc1OB 23. We herein report the synthesis of these two compounds and also that of other modified analogs that are highly specific acceptors for the two sulfotransferases. Appropriately protected 1-thio-glycosides 7, 8, and 10 were employed as glycosyl donors for the synthesis of our target compounds. 相似文献
5.
Andrew B. Clippingdale Wei-Lan He Mary Macris John D. Wade Colin J. Barrow 《Letters in Peptide Science》1999,6(5-6):289-293
Modifications to secondary structure and fibril formation caused by multiple acetylHmb backbone amide protection of Alzheimer's disease A(1-40) were investigated using circular dichroism spectroscopy and electron microscopy. Penta(acetylHmb)A(1-40) was observed to have a reduced ability to form -helix and -sheet structures under the same solution conditions as the native peptide, with -helical propensity being reduced more significantly than -sheet propensity. Further, acetylHmb backbone protection was found to alter A(1-40) interaction with SDS-micelles by preventing -helix formation. A fibril formation, a characteristic property of this peptide, was also not observed for penta(acetylHmb)A(1-40). 相似文献
6.
Dong-Hyun Kim Norihiro Azuma Hideyuki Tanaka Choemon Kanno 《Glycoconjugate journal》1998,15(4):361-369
The structures of the N-linked sugar chains in the PAS-6 glycoprotein (PAS-6) from the bovine milk fat globule membrane were determined. The sugar chains were liberated from PAS-6 by hydrazinolysis, and the pyridylaminated sugar chains were separated into a neutral (6N) and two acidic chains (6M and 6D), the acidic sugar chains then being converted to neutral sugar chains (6MN and 6DN). 6N was separated into two neutral fractions (6N13 and 6N5.5), while 6MN and 6DN each gave a single fraction (6MN13 and 6DN13). The structure of 6N5.5, which was the major sugar chain in PAS-6, is proposed to be Man16 (Man13) Man14GlcNAc14GlcNAc-PA; 6N13, 6MN13 and 6DN13 are proposed to be Gal13Gal14GlcNAc12Man16 (Gal13Gal14GlcNAc12Man13) Man14GlcNAc14 (Fuc16)GlcNAc-PA;6M and 6D had 1 or 2 additional NeuAc residues at the non-reducing ends of 6MN13 and 6DN13, respectively. © 1998 Rapid Science Ltd 相似文献
7.
When 7721 human hepatocarcinoma cells were treated with 100nm phorbol-12-myristate-13-acetate (PMA), the activity ofN-acetylglucosaminyltransferase V(GnT-V) in the cells varied in accordance with the activity of membranous protein kinase C (PKC), but not with that of cytosolic PKC. Quercetin, a non-specific inhibitor of Ser/Thr protein kinase, andd-sphingosine and staurosporine, two specific inhibitors of PKC, blocked the activation of membranous PKC and GnT-V by PMA. Among the three inhibitors, quercetin was least effective. The inhibitory rates of quercetin and staurosporine toward membranous PKC and GnT V were proportional to the concentrations of the two inhibitors. The activities of GnT V and membranous protein kinase A (PKA) were also induced in parallel by dibutyryl cAMP (db-cAMP) and this induction was blocked by a specific PKA inhibitor. When cell free preparations of 7721 cells and human kidney were treated with alkaline phosphatase (ALP) to remove the phosphate groups, the GnT V activities were decreased. These results suggest that GnT V may be activated by membranous PKC or PKA, indirectly or directly, via phosphorylation of Ser/Thr residues.Abbreviations UDP
uridine diphospho-
- GnT
N-acetylglucosaminyltransferase
- GlcNAc Gn
N-acetylglucosamine
- M
mannose
- PMA
phorbol-12-myristate-13-acetate
- PKC
protein kinase C
- PKA
protein kinase A
- cAMP
adenosine 3, 5-cyclic monophosphate
- db-cAMP
dibutyryl cAMP
- TPK
tyrosine protein kinase
- MES
2-[N-morpholino]ethanesulfonic acid
- DTT
dithiothreitol
- PMSF
phenylmethylsulfonyl fluoride
- EDTA
ethylene diamine tetraacetic acid
- EGTA
glycol-bis-(-aminoethyl) etherN,N,N,N-tetraacetic acid
- PA
2-aminopyridine
- ALP
alkaline phosphatase
- C2C2
GlcNAc1-2 Man1-6(GlcNAc1-2Man1-3)ManR
- C2,4C2
GlcNAc1-2Man1-6(GlcNAc1-4[GlcNAc1-2]Man1-3)ManR
- C2C2,6
GlcNAc1-6[GlcNAc1-2]Man1-6(GlcNAc1-2Man1-3)ManR
- C2,4C2,6
GlcNAc1-6[GlcNAc1-2]Man1-6(GlcNAc1-4[GlcNAc1-2]Man1-3)ManR where R=1-4GlcNAc1-4GlcNAcAsnX
- Gn2M3Gn2-PA
C2C2 where R=1-4GlcNAc1-4GlcNAc-PA
- Gn3M3Gn2-PA
C2C2,6 where R=1-4GlcNAc1-4GlcNAc-PA 相似文献
8.
Guiyun Xu Takashi Suzuki Yasuhiro Maejima Tohru Mizoguchi Mamoru Tsuchiya Makoto Kiso Akira Hasegawa Yasuo Suzuki 《Glycoconjugate journal》1995,12(2):156-161
The sialidase of swine influenza A viruses of N1 and N2 subtypes, isolated from 1930 to 1992, was studied for substrate specificity with ganglio-series, lacto-series type II and GM3 gangliosides containing Neu5Ac2-3Gal, Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. All viral sialidases tested showed that the activity for hydrolysing substrates with Neu5Ac2-3Gal was higher than the activities with Neu5Gc2-3Gal and Neu5Ac2-6Gal linkages. When GM1b, GM3 and sialylparagloboside were used as substrates, the earliest strain (A/Wisconsin/15/30 H1N1, isolated in 1930) showed the activity ratio of Neu5Ac2-6Gal to Neu5Ac2-3Gal to be 0.13:0.2, and the ratio Neu5Gc2-3Gal/Neu5Ac2-3Gal to be 0.19:0.37, while those strains isolated from 1978 to 1992 exhibited ratios of 0.29:0.58 for Neu5Ac2-6Gal/Neu5Ac2-3Gal and 0.51:0.76 for Neu5Gc2-3Gal/Neu5Ac2-3Gal. The above results indicate that the substrate specificities of sialidases from swine influenza A viruses towards sialyl linkages and the molecular species of sialic acid are related to the year of isolation, i.e. strains isolated after 1978 exhibited higher activity towards Neu5Ac2-6Gal and Neu5Gc2-3Gal linkages when compared with strains isolated in an earlier year, 1930.Abbreviation Neu5Ac
5-N-acetylneuraminic acid
- Neu5Gc
5-N-glycolyneuraminic acid
- Gal
d-galactose
- Glc
d-glucose
- Cer
Ceramide
- II3(Neu5Ac)Lac
Neu5Ac2-3Gal1-4Glc
- GM3(Neu5Ac2-3Gal)
Neu5Ac2-3Gal1-4Glc1-Cer
- GM3(Neu5Gc2-3Gal)
Neu5Gc2-3Gal1-4Glc1-Cer
- GM1b(Neu5Ac2-3Gal)
Neu5Ac2-3Gal1-3GalNac1-4Gal1-4Glc1-Cer
- GMlb(Neu5Gc2-3Gal)
Neu5Gc2-3Gal1-3GalNAc1-4Gal1-4Glc1-Cer
- IV3(Neu5Ac)nLc4Cer
Neu5Ac2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer
- IV3(Neu5Gc)nLc4Cer
Neu5Gc2-3Gal1-3GlcNAc1-4Gal1-4Glc1-Cer
- IV6(Neu5Ac)nLc4Cer
Neu5Ac2-6Gal1-3GlcNAc1-4Gal1-4Glc1-Cer
- TDC
taurodeoxycholate. 相似文献
9.
Summary The potential of-lactams as intermediates for the access to- and-amino acid-derived peptides is shortly reviewed, with major focus on the technologies developed in our group. The two general strategies lie, on one side, in the oxidative ring expansion of 3-hydroxy-lactams toN-carboxy-amino acid anhydrides or Leuch's anhydrides and subsequent coupling with-amino acid esters and, on the other side, in the nucleophilic ring opening ofN-Boc--lactams. Both approaches have been successfully applied to the synthesis of,-diamino acid,-amino--hydroxy acid, polyhydroxylated-amino acid,,-disubstituted-amino acid,-amino acid,-amino--hydroxy acid and,-disubstituted-amino acid derived peptides. Because of the mild reaction conditions needed for the above transformations and the highly stereoselective procedures employed for the construction of the starting-lactam ring, the whole process allows the production of optically pure final products. 相似文献
10.
Cotton fibres possess several -glucanase activities which appear to be associated with the cell wall, but which can be partially solubilised in buffers. The main activity detected was that of an exo-(13)--d-glucanase (EC 3.2.1.58) but which also had the characteristics of a -glucosidase (EC 3.2.1.21). Endo-(13)--d-glucanase activity (EC 3.2.1.39) and much lower levels of (14)--d-glucanase activity were also detected. The exo-(13)--glucanase showed a maximum late on (40 days post-anthesis) in the development of the fibres, whereas the endo-(13)--glucanase activity remained constant throughout fibre development. The -glucanase complex associated with the cotton-fibre cell wall also functions as a transglucosylase introducing, inter alia, (16)--glucosyl linkages into the disaccharide cellobiose to give the trisaccharide 4-O--gentiobiosylglucose.Abbreviations CMC
carboxymethylcellulose
- ONPG
o-nitrophenyl--d-glucopyranoside
- TLC
thin-layer chromatography
Presented at the Third Cell Wall Meeting held in Fribourg in 1984 相似文献
11.
George Britton David J. Brown Trevor W. Goodwin Franz J. Leuenberger Arno J. Schocher 《Archives of microbiology》1977,113(1-2):33-37
The main carotenoid of Flavobacterium strain R1560 has been identified as (3R,3R)-zeaxanthin. Also present were small amounts of 15-cis-phytoene, phytofluene, -carotene (7,8,7,8-tetrahydro-, -carotene plus 7,8,11,12-tetrahydro-, -carotene), neurosporene, lycopene, -zeacarotene, -carotene, -carotene, -cryptoxanthin, rubixanthin, 3-hydroxy--zeacarotene and several apo-carotenals. Zeaxanthin production was inhibited by nicotine (10 mM), and lycopene and rubixanthin accumulated. The biosynthesis of zeaxanthin is discussed in terms of pathways and also of half-molecule reaction sequences. The presence of zeaxanthin may be a characteristic of a group of Flavobacterium species, and may thus be useful in the taxonomic classification of these organisms. 相似文献
12.
The diversity of isoforms of retinoic acid (RA) receptors (RARs) and of DNA sequences of retinoic acid-responsive elements (RAREs) suggests the existence of selectivities in the RAR/RARE recognition or in the subsequent gene modulation. Such selectivities might be particularly important for RAREs involved in positive feedback, eg. the RAR RARE. In the present work we found that in several epithelial cell lines, reporter constructs containing the RAR RARE linked to the HSV-tk promoter were transactivated in the presence of RA by endogenous RARs and co-transfected RAR1 and RAR2 isoforms, but not by RAR1. On the contrary, this latter isoform behaved towards the RAR RARE as an inhibitor of the transactivation produced by endogenous RARs and by cotransfected RAR1 and RAR2. RAR1 also behaved as an antagonist of the transactivation produced by cotransfected RXR. The natural RAR gene promoter or RAR RARE tk constructs were not activated by the endogenous receptors of normal human keratinocytes (NHK), which are known to contain predominantly RAR1. It was, however, possible to activate to a certain extent RAR RARE-reporter constructs in NHK by co-transfecting RAR1, RAR2 or RXR. The antagonist behavior of RAR1 towards the RAR RARE may explain why in certain cell types such as keratinocytes, RAR is neither expressed nor induced by RA.Abbreviations DMEM
Dulbecco's modified Eagle medium
- DMSO
dimethyl sulfoxide
- FCS
fetal calf serum
- MEM
minimal Eagle medium
- NHK
normal human keratinocyte
- RA
retinoic acid
- RAR
retinoic acid receptor
- RARE
retinoic acid responsive element
- TRE
thyroid responsive element
- VDRE
vitamin D response element
- RXR
retinoid X receptor 相似文献
13.
The twelve Cys and eight of the non-Cys residues are invariant in the glycoprotein hormone subunits from a variety of mammalian species. -Gin-54 of human lutropin (hLH) and choriogonadotropin (hCG) is one of these invariant amino acid residues. A single AG mutation in the LH gene of a patient presenting with hypogonadism resulted in the replacement of Gin-54 with Arg [1]. The authors also reported that an expressed mutant of hLH, with Arg replacing Gin-54, associated with the subunit, but there was no demonstrable binding of the mutant hormone to receptor. We have replaced Gin-54 in hCG with Glu and with Lys using site-directed mutagenesis. The expression plasmids pRSV-hCG (wild-type and mutants) were transiently transfected into CHO cells containing a stably integrated gene for bovine , and the media were analyzed for holoproteins, which were characterizedin vitro using competitive binding and steroidogenic assays with MA-10 cells. hCG(Glu-54) bound to almost as well as hCG wild-type, and the resulting heterodimer competed with [125l]hCG binding to the LH/CG receptor and stimulated progesterone production to the same extent as the wild-type control. However, the apparent potencies, as judged by ED50s, were less than those of the wild-type control, the effect being more pronounced in binding than in steroidogenesis. In contrast, hCG(Lys-54) associated very poorly with . Our results suggest that while Gin-54 in hCG participates in receptor binding, its major function appears to involve binding. Such dual functionality leads to interesting models for holoprotein formation and receptor binding. 相似文献
14.
Sachio Hayashi Takenobu Yoshiyama Norito Fujii Satoru Shinohara 《Biotechnology letters》2000,22(18):1465-1469
A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively. 相似文献
15.
Integrin 5 1 and 2 1 are the major integrin receptors in human hepatocytes. However, in human hepatocellular carcinoma cells it was found that the expression of integrin 5 1 was decreased and another integrin 6 1 increased. In this study, the SMMC7721 human hepatocellular carcinoma cells cotransfected or singlely transfected with integrin 5 and/or 1 cDNAs were established, and designated 5 1.6-7721, 5.3-7721, and 1.6-7721 cell lines, respectively. Transfection with cDNAs of integrin 5 and 1 subunits resulted in the overexpression of each integrin and modified biological properties, including a slowed growth rate, changes in the cell cycle from 15.5% of control cells in the G2/M phase to 12.1%, 9.6% and 9.4% in 5.3-7721, 1.6-7721, 5 1.6-7721, respectively, and a decrease in the Cell Mitosis Index from 1.6 in controls to 0.96, 0.95, and 0.72, and 34%, 28% and 52% derived from colony forming ability, respectively. Tumorigenicity was also tested in nude mice with inoculation of cells subcutaneously. Tumor masses growing in nude mice following inoculation with 1.6-7721,and 5 1.6-7721 cells weighed only 52% or 31% those of control cells. These results indicated that deletion or low expression of integrin 5 1 may play an important role in the development of hepatocellular carcinoma. Therefore, induction of expression of the integrin 5 1 in malignant cells could be a potential means of treating hepatocellular carcinoma. 相似文献
16.
Cornelis H. Hokke Jos G. M. van der Ven Johannis P. Kamerling Johannes F. G. Vliegenthart 《Glycoconjugate journal》1993,10(1):82-90
Incubation of synthetic Man\1-4GlcNAc-OMe, GalNAc1-4GlcNAc-OMe, Glc1-4GlcNAc-OMe, and GlcNAc1-4GlcNac-OMe with CMP-Neu5Ac and rat liver Gal1-4GlcNAc (2-6)-sialyltransferase resulted in the formation of Neu5Ac2-6Man1-4GlcNAc-OMe, Neu5Ac2-6GalNAc1-4GlcNAc-OMe, Neu5Ac2-6Glc1-4GlcNAc-OMe and Neu5Ac2-6GlcNAc1-4GlcNAc-OMe, respectively. Under conditions which led to quantitative conversion of Gal1-4GlcNAc-OEt into Neu5Ac2-6Gal1-4GlcNAc-OEt, the aforementioned products were obtained in yields of 4%, 48%, 16% and 8%, respectively. HPLC on Partisil 10 SAX was used to isolate the various sialyltrisaccharides, and identification was carried out using 1- and 2-dimensional 500-MHz1H-NMR spectroscopy.Abbreviations 2D
2-dimensional
- CMP
cytidine 5-monophosphate
- CMP-Neu5Ac
cytidine 5-monophospho--N-acetylneuraminic acid
- COSY
correlation spectroscopy
- DQF
double quantum filtered
- HOHAHA
homonuclear Hartmann-Hahn
- MLEV
composite pulse devised by M. Levitt
- Neu5Ac
N-acetylneuraminic acid
- Neu5Ac2en
2-deoxy-2,3-didehydro-N-acetylneuraminic acid 相似文献
17.
Rabbit antisera were raised against -(16)-galactotetraose coupled to bovine serum albumin (Gal4-BSA). The antisera reacted with arabinogalactan-proteins (AGPs) isolated from seeds, roots, or leaves of radish (Raphanus sativus L.) as revealed by immunodiffusion analysis. Extensive removal of -l-arabinofuranosyl residues from these AGPs enhanced the formation of precipitin with the antisera. The antisera did not react with such other polysaccharides as soybean arabinan-4-galactan, -(14)-galactan, and -(13)-galactan, indicating their high specificity toward the consecutive -(16)-galactosyl side chains of AGPs. The antibodies were purified by affinity chromatography on a column of immobilized -(16)-galactotetraose as ligand. The specificity of the antibodies toward consecutive (16)-linked -galactosyl residues was confirmed by enzyme-linked immunosorbent assay for hapten inhibition against Gal4-BSA as antigen, which revealed that -(16)-galactotriose and-tetraose were potent inhibitors, while -(13)-or -(14)-galactobioses and -trioses were essentially unreactive. Electron-microscopic observation of immunogold-stained tissues demonstrated that AGPs were localized in the middle lamella as well as at the plasma membrane of primary roots of radish. Agglutination of protoplasts prepared from cotyledons occurred with the antibodies, supporting the evidence for localization of AGPs in the plasma membrane. The antibody-mediated agglutination was inhibited by addition of AGPs or -(16)-galactotetraose.Abbreviations AGP
arabinogalactan-protein
- BSA
bovine serum albumin
- ELISA
enzyme-linked immunosorbent assay
- FITC
fluorescein isothiocyanate
- Gal3-BSA
-(16)-galactotriose coupled to BSA
- Gal4-BSA
-(16)-galactotetraose coupled to BSA
- Ig
immunoglobulin
- 4-Me-GlcpA
4-O-methyl-d-glucopyranosyluronic acid
- Mr
relative molecular mass
The authors wish to thank Dr. J. Ohnishi of Department of Biochemistry, Saitama University, for his help in preparing protoplasts. 相似文献
18.
We have developed a new method for the large scale preparation of pyridylaminated (PA-) oligosaccharides from glycoproteins. Phenol/chloroform extration was adapted for the removal of protein and excess 2-aminopyridine, improving the efficiency of preparation. From a 2.5 g sample of human apo-transferrin, 25–30 mol of agalacto biantennary PA-oligosaccharide could be obtained. By increasing the concentration of PA-oligosaccharide substrate, we were able to detect a very low level ofN-acetylglucosaminlytransferase IV activity in CHO cell extracts.Abbreviations PA
2-aminopyridine
- SDS
sodium dodecyl sulfate
- GlcNAc
N-acetylglucosamine
- GnT
N-acetylglucosaminyltransferase
- Gn,Gn-bi-PA
GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine
- Gn,Gn,Gn-tri-PA
GlcNAc1-2(GlcNAc1-4)Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine
- Gn,Gn,Gn-trí-PA
GlcNAc1-2Man1-3({GlcNAc1-2(GlcNAc1-6)Man1-6})Man1-4GlcNac1-4GlcNAc-2-aminopyridine
- Gn,(Gn),Gn-bi-PA
GlcNAc1-2Man1-3(GlcNAc1-4)(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine 相似文献
19.
Folkert Reck Matthias Springer Ernst Meinjohanns Hans Paulsen Inka Brockhausen Harry Schachter 《Glycoconjugate journal》1995,12(6):747-754
UDP-GlcNAc:Man1-3R 1-2-N-acetylglucosaminyltransferase I (GlcNAc-T I; EC 2.4.1.101) catalyses the conversion of [Man1-6(Man1-3)Man1-6][Man1-3]Man-O-R to [Man1-6(Man1-3)Man1-6] [GlcNAc1-2Man1-3]Man-O-R (R=1-4GlcNAc1-4GlcNAc-Asn-X) and thereby controls the conversion of oligomannose to complex and hybrid asparagine-linked glycans (N-glycans). GlcNAc-T I also catalyses the conversion of Man1-6(Man1-3)Man-O-octyl to Man1-6(GlcNAc1-2Man1-3)Man-O-octyl. We have therefore tested a series of synthetic analogues of Man1-6(Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T I. The 2-deoxy and the 3-, 4- and 6-O-methyl derivatives are all good substrates confirming previous observations that the hydroxyl groups of the Man1-6 residue do not play major roles in the binding of substrate to enzyme. In contrast, all four hydroxyl groups on the Man1-3 residue are essential since the corresponding deoxy derivatives either do not bind (2- and 3-deoxy) or bind very poorly (4- and 6-deoxy) to the enzyme. The 2- and 3-O-methyl derivatives also do not bind to the enzyme. However, the 4-O-methyl derivative is a substrate (K
m
=2.6mm) and the 6-O-methyl compound is a competitive inhibitor (K
i=0.76mm). We have therefore synthesized various 4- and 6-O-alkyl derivatives, some with reactive groups attached to anO-pentyl spacer, and tested these compounds as reversible and irreversible inhibitors of GlcNAc-T I. The 6-O-(5-iodoacetamido-pentyl) compound is a specific time dependent inhibitor of the enzyme. Four other 6-O-alkyl compounds showed competitive inhibition while the remaining compounds showed little or no binding indicating that the electronic properties of the attachedO-pentyl groups influence binding.Abbreviations GlcNAc-T I
UDP-GlcNAc:Man1-3R 1-2-N-acetylglucosaminyltransferase I (EC 2.4.1.101)
- GlcNAc-T II
UDP-GlcNAc:Man1-6R 1-2-N-acetylglucosaminyltransferase II (EC 2.4.1.143)
- MES
2-(N-morpholino)ethane sulfonic acid monohydrate 相似文献
20.
The cDNA clones of two potato -tubulin genes were isolated from a tuberising stolon tip library. Analysis of 20 positive clones showed that they represented one or another of two different but very similar -tubulin genes, designated TUBST1 and TUBST2. The expression pattern of -tubulin genes in the potato plant was investigated by RNA blot analysis and by RT-PCR. Southern analysis of potato genomic DNA with coding and non-coding -tubulin probes revealed that there are multiple -tubulin genes in the potato genome and that there is likely to be considerable divergence in the 3 non-coding sequences. Phylogenetic analysis of plant -tubulin genes is described. 相似文献