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1.
Tadashi II Masayuki Kubota Satoshi Okuda Takashi Hirano Mamoru Ohashi 《Glycoconjugate journal》1995,12(2):162-172
Negative-ion fast atom bombardment tandem mass spectrometry has been used in the characterization of non-, mono-, di- and trisulfated disaccharides from heparin and heparan sulfate. The positional isomers of the sulfate group of monosulfated disaccharides were distinguished from each other by negative-ion fast atom bombardment tandem mass spectra, which provide an easy way of identifying the positional isomers. This fast atom bombardment collision induced dissociation mass spectrometry/mass spectrometry technique was also applied successfully to the characterization of di- and trisulfated disaccharides.Abbreviations FABMS
fast atom bombardment mass spectrometry
- CID
collision induced dissociation
- MIKE
mass analysed ion kinetic energy
- MS/MS
mass spectrometry/mass spectrometry
- HPLC
high performance liquid chromatography
- UA
d-gluco-4-enepyranosyluronic acid
- CS
chondroitin sulfate
- DS
dermatan sulfate
- HA
hyaluronan
- Hep
heparin
- HS
heparan sulfate
- UA(14) GlcNAc
2-acetamido-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA(14)GlcNAc6S
2-acetamido-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA2S(14)GlcNAc
2-acetamido-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA2S(14)GlcNAc6S
2-acetamido-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA(14)GlcN6S
2-amino-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA2S(14)GlcN
2-amino-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA2S(14)GlcN6S
2-amino-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA(14)GlcNS
2-deoxy-2-sulfamino-4-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA(14)GlcNS6S
2-deoxy-2-sulfamino-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA2S(14)GlcNS
2-deoxy-2-sulfamino-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA2S(14)GlcNS6S
2-deoxy-2-sulfamino-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA(13)GalNAc
2-acetamido-2-deoxy-3-O-(-d-Gluco-4-enepyranosyluronic acid)-d-galatose
- UA(13)GalNAc4S
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose
- UA(13)GalNAc6S
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose
- UA2S(13)GalNAc
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-galactose
- UA2S(13)GalNAc4S
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose
- UA2S(13)GalNAc6S
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose
- UA(13)GalNAcDiS
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4,6-di-O-sulfo-d-galactose
- UA(13)GlcNAc
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose. 相似文献
2.
Subroto Chatterjee Tavia Cleveland Wan-Yang Shi Jin-Ichi Inokuchi Norman S. Radin 《Glycoconjugate journal》1996,13(3):481-486
We have studied the effects ofD-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) and itsL-enantiomer on glycosphingolipids in cultured normal human kidney proximal tubular cells. We found thatD-PDMP exerted a concentration-dependent reduction in the metabolic labelling and cellular levels of glucosylceramide (GlcCer), lactosylceramide (LacCer), and the globo-series glycosphingolipids, GbOse3Cer and GbOse4Cer. It also directly inhibited the activity of UDP-glucose:ceramide 1 4-glucosyltransferase (GlcT-1) and UDP-galactose: GlcCer 1 4 galactosyltransferase (GalT-2). In contrast,L-PDMP had opposite effects on the metabolic labelling of GlcCer, LacCer, and GbOse3Cer. The levels of GlcCer and LacCer were increased, while the labelling and level of GbOse4Cer were strongly reduced. Purified GalT-2 from human kidney was inhibited byD-PDMP and stimulated byL-PDMP. It appears likely that the different glycosphingolipid glycosyltransferases possess similar binding sites for the ceramide moiety, which are blocked by binding toD-PDMP and, in the case of GbOse4Cer synthase, byL-PDMP as well. The stimulatory effects ofL-PDMP on GlcCer and LacCer synthases may be the result of binding to a modulatory site on the glycosyltransferases; in intact cells, the enzyme-analog complex may afford protection against the normal catabolic inactivation of the enzymes.Abbreviations GalT-2
UDP-galactose:GlcCer -galactosyltransferase
- GbOse3Cer
Gal1 4Gal1 GlcCer
- GbOse4Cer
GalNAc1 3Gal1 4Gal1 GlcCer
- GlcCer
glucosylceramide
- GlcT-1
UDP-glucose:ceramide -glucosyltransferase
- GSLs
glycosphingolipids
- LacCer
lactosylceramide
- PDMP
threo-1-phenyl-2-decanolyamino-3-morpholino-1-propanol 相似文献
3.
Yin Kiong Hoh Hock-Hin Yeoh Teck Koon Tan 《Applied microbiology and biotechnology》1992,37(5):590-593
Summary Two extracellular -glucosidases (EC 3.2.1.21) were isolated from Aspergillus niger USDB 0827 and A. niger USDB 0828, and their physical and kinetic properties studied. Both enzymes were very similar in terms of molecular size (230000 Da), pH optimum (pH 4.6), temperature optimum (65° C), stability at high temperatures and substrate preferences. They were capable of hydrolysing -linked disaccharides, phenyl -d-glucoside, p-nitrophenyl -d-glucoside (PNPG), o-nitrophenyl -d-glucoside, salicin and methyl -d-glucoside but lacked activity towards -linked disaccharides, a range of p-nitrophenyl monoglycosides and p-nitrophenyl diglycosides. Both -glucosidases were better at hydrolysing cellobiose than cellotriose, cellotetraose or cellopentaose. For both enzymes, glucose showed competitive inhibition with PNPG as substrate but had no effect with cellobiose. However, the two -glucosidases differed in inhibition by glucono-1,5-lactone and affinity for cellobiose. -Glucosidase from A. niger USDB 0827 also gave lower specific activity, and was more susceptible to metal ions (Ag+, Fe2+ and Fe3+) inhibition than that of A. niger USDB 0828.
Correspondence to: Y. K. Hoh 相似文献
4.
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
5.
Shoot tips of wheat as an alternative source for regenerable embryogenic callus cultures 总被引:5,自引:0,他引:5
Shoot tips of Triticum aestivum L. cvs. Turbo and Nandu, both summer wheat varieties, were excised from 4 and 10 day-old seedlings, and used for induction of embryogenic callus. A modified L3 medium, supplemented with 10 M 2,4-dichlorophenoxyacetic acid (2,4-d) for culture initiation, and 5 M 2,4-d for subculturing, was optimal; 90% of 4 day-old Turbo seedlings formed embryogenic callus. Optimal plant regeneration was achieved from callus incubated on a modified MS medium without 2,4-d, but supplemented with 2.22 M 6-benzylaminopurine and 0.27 M naphthaleneacetic acid. Plantlets formed via embryogenesis from all embryogenic Turbo calli initiated from 4 day-old explants, with a mean number of 8 regenerants per explant. Regeneration occured via embryogenesis only. Results obtained using Nandu were within the same range.Abbreviations BA
6-benzylaminopurine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- NAA
naphthaleneacetic acid 相似文献
6.
The main polysaccharide component of the thickened cell walls in the storage parenchyma of Lupinus angustifolius L. cotyledons is a linear (1 4)--linked d-galactan, which is mobilised after germination (L.A. Crawshaw and J.S.G Reid, 1984, Planta 160, 449–454). The isolation from the germinated cotyledons of a -d-galactosidase or exo-(1 4)--d-galactanase with a high specificity for the lupin galactan is described. The enzyme, purified using diethylaminoethyl-cellulose, carboxymethyl-cellulose and affinity chromatography on lactose-agarose, gave two bands (major 60 kDa, minor 45 kDa) on sodium dodecyl sulphate-gel electrophoresis, and two similar bands on isoelectric focusing (major, pI 7.0, minor pI 6.7, both apparently possessing enzyme activity). The minor component cross-reacted with an antiserum raised against, and affinity-purified on, the major band. Both components had a common N-terminal sequence. The minor component was probably a degradation product of the major one. The enzyme had limited -galactosidase action, catalysing the hydrolysis of p-nitrophenyl--d-galactopyranoside and (1 4)- and (1 6)--linked galactobioses. Lactose [-d-galactopyranosyl-(1 4)-d-glucose] was hydrolysed only very slowly and methyl--d-galactopyranoside not at all. Lupin galactan was hydrolysed rapidly and extensively to galactose, whereas other cell-wall polysaccharides (xyloglucan and arabinogalactan) with terminal non-reducing -d-galactopyranosyl residues were not substrates. A linear (1 4)--linked galactopentaose was hydrolysed efficiently to the tetraose plus galactose, but further sequential removals of galactose to give the tetraose and lower homologues occurred more slowly. Galactose, -galactonolactone and Cu+2 were inhibitory. No endo--d-galactanase activity was detected in lupin cotyledonary extracts, whereas exo-galactanase activity varied pari passu with galactan mobilisation. Exo-galactanase protein was detected, by Western immunoblotting of cotyledon extracts, just before the activity could be assayed and then increased and decreased in step with the enzyme activity. The exo-galactanase is clearly a key enzyme in galactan mobilisation and may be the sole activity involved in depolymerising the dominant (1 4)--galactan component of the cell wall.Abbreviations CM
carboxymethyl
- DEAE
diethylaminoethyl
- SDS-PAGE
sodium dodecyl sulphate-polyacrylamide gel electrophoresis
- TLC
thin-layer chromatography
We wish to thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for the award of a studentship to M.S. Buckeridge, and the Government of São Paulo State, Brazil for granting him leave of absence. We are grateful to Dr. Amanda Heyller (Unilever Research Laboratory, Colworth House, Bedford, UK) for N-terminal sequence determinations, to Dr. Stuart Wilson (Stirling) for preparing gelatin SDS-gels and to Cristina Fanutti (Stirling) for purifying the xyloglucan oligosaccharide. 相似文献
7.
Summary The taste buds of the circumvallate papillae have been examined by electron microscopy in OsO4-fixed, PTA stained material or after KMnO4 fixation. The microvilli of the receptor cells have terminal dilatations which presumably give an increased surface area for transduction. The extracellular spaces at the necks of the receptor cells near the bases of the microvilli are interrupted by closed contacts.The synapses have a well defined synaptic cleft suggesting a chemical rather than an electrical mode of transmission. Synaptic membrane specialisations differ from the membrane thickenings of other types of synapse. Presynaptic dense projections are present but there is no well define postsynaptic thickening. Vesicles occur in both pre- and postsynaptic components, but it is debatable whether or not they should be termed synaptic vesicles.
Acknowledgements. We are indebted to Professor J. Z. Young, F. R. S., for his stimulating support, and to Mr. S. Waterman for skilled photography. 相似文献
8.
Lai-Xi Wang Nadejda V. Pavlova Su-Chen Li Yu-Teh Li Yuan C. Lee 《Glycoconjugate journal》1996,13(3):359-365
4-Methylumbelliferyl 6-O-benzyl--d-lactoside (6Bn-MU-Lac) and some related compounds were synthesizedvia different selective reactions including phase-transfer glycosylation. Their suitability as substrates for a fluorometric assay of ceramide glycanase (CGase) was evaluated. Among others, the 6Bn-MU-Lac, which is resistant to exogalactosidase, was found to be a suitable substrate for routine assay of the CGase activity. For American leech CGase, theK
m value is 0.232 mM at pH 5.
Abbreviations: CGase, ceramide glycanase; Gal, galactose; Glc, Glucose; Lac, lactose; MU, 4-methylumbelliferone; MU-Lac, 4-methylumbelliferyl -d-lactoside; bBn-Lac, 6-O-benzyl-lactose; 6Bn-MU-Lac, 4-methylumbelliferyl 6-Obenzyl--d-lactoside; 46Bd-MU-Lac, 4-methylumbelliferyl 4,6-O-benzylidene--d-lactoside; MU-Cel, 4-methylumbellifery -d-cellobioside; 46Bd-MU-Cel, 4-methylumbelliferyl 4,6-O-benzylidene--d-cellobioside; TLC, thin layer chromatography;1H-NMR, proton nuclear magnetic resonance; GSL, glycosphingolipids; CSA, 10-camphorsulfonic acid. See Scheme 1 for chemical structures. 相似文献
9.
The properties of the -2-l-fucosyltransferases in submaxillary gland preparations from blood group ABH secrefors and non-secretors were compared. The level of activity in the non-secretor gland homogenates amounted to about 5% only of that found in the secretor gland preparations. The enzymes from the two sources differed in solubility properties, charge and affinities for donor and acceptor substrates. The enzyme from secretor glands showed a preference for acceptors with Type 1 [d-galactosyl(1–3)-N-acetyl-d-glucosamine] structures whereas the enzyme from non-secretor glands had a preference for Type 2 [d-galactosyl(1–4)-N-acetyl-d-glucosamine] structures.These results demonstrate that expression of the secretor gene (Se) is associated with a molecular form of the -2-l-fucosyltransferase that is different from the species present in the same tissue when theSe gene is not expressed. 相似文献
10.
Summary
Darwin's phrase place in natural economy, andSpencer's term correspondence can be regarded as first attempts to express the organism-environment relationships. The same concept has more recently been approached from the point of view of (1) life-form, (2) external activities, and (3) habitat. Though all these points are interlocking, they have been stressed differently in the writings of American and European ecologists. It is proposed that the term niche would be most useful and rational if applied to the total of relationships between a living organism (population, species) and its complete environment, both biotic and abiotic. 相似文献
11.
Yoshiharu Matahira Atsushi Tashiro Toshinari Sato Hirokazu Kawagishi Taichi Usui 《Glycoconjugate journal》1995,12(5):664-671
N-acetylhexosaminidase fromNocardia orientalis catalysed the synthesis of lacto-N-triose II glycoside (-d-GlcNAc-(1-3)--d-Gal-(1-4)--d-Glc-OMe,3) with its isomers -d-GlcNAc-(1-6)--d-Gal-(1-4)--d-Glc-OMe (4) and -d-Gal-(1-4)-[-d-GlcNAc-(1-6)]--d-Glc-OMe (5) throughN-acetylglucosaminyl transfer fromN,N-diacetylchitobiose (GlcNAc2) to methyl -lactoside. The enzyme formed the mixture of trisac-charides3, 4 and5 in 17% overall yield based on GlcNAc2, in a ratio of 20:21:59. Withp-nitrophenyl -lactoside as an acceptor, the enzyme also producedp-nitrophenyl -lacto-N-trioside II (-d-GlcNAc-(1-3)--d-Gal-(1-4)--d-Glc-OC6H4NO2-p,6) with its isomers -d-GlcNAc-(1-6)--d-Gal-(1-4)--d-Glc-OC6H4NO2-p (7) and -d-Gal-(1-4)-[-d-GlcNAc-(1-6)]--d-Glc-OC6H4NO2-p (8). In this case, when an inclusion complex ofp-nitrophenyl lactoside acceptor with -cyclodextrin was used, the regioselectivity of glycosidase-catalysed formation of trisaccharide glycoside was substantially changed. It resulted not only in a significant increase of the overall yield of transfer products, but also in the proportion of the desired compound6.Abbreviations GlcNAc2
2-acetamido-2-deoxy--d-glucopyranosyl-(1-4)-2-acetamido-2-deoxy-d-glucose
- NAHase
N-acetylhexosaminidase
- -CD
-cyclodextrin 相似文献
12.
Folkert Reck Ernst Meinjohanns Matthias Springer Roland Wilkens Johannes A. L. M. Van Dorst Hans Paulsen Gabriele Möller Inka Brockhausen Harry Schachter 《Glycoconjugate journal》1994,11(3):210-216
UDP-GlcNAc: Man1-6R (1-2)-N-acetylglucosaminyltransferase II (GlcNAc-T II; EC 2.4.1.143) is a key enzyme in the synthesis of complexN-glycans. We have tested a series of synthetic analogues of the substrate Man1-6(GlcNAc1-2Man1-3)Man-O-octyl as substrates and inhibitors for rat liver GlcNAc-T II. The enzyme attachesN-acetylglucosamine in 1-2 linkage to the 2-OH of the Man1-6 residue. The 2-deoxy analogue is a competitive inhibitor (K
i=0.13mm). The 2-O-methyl compound does not bind to the enzyme presumably due to steric hindrance. The 3-, 4- and 6-OH groups are not essential for binding or catalysis since the 3-, 4- and 6-deoxy and -O-methyl derivatives are all good substrates. Increasing the size of the substituent at the 3-position to pentyl and substituted pentyl groups causes competitive inhibition (K
i=1.0–2.5mm). We have taken advantage of this effect to synthesize two potentially irreversible GlcNAc-T II inhibitors containing a photolabile 3-O-(4,4-azo)pentyl group and a 3-O-(5-iodoacetamido)pentyl group respectively. The data indicate that none of the hydroxyls of the Man1-6 residue are essential for binding although the 2- and 3-OH face the catalytic site of the enzyme. The 4-OH group of the Man-O-octyl residue is not essential for binding or catalysis since the 4-deoxy derivative is a good substrate; the 4-O-methyl derivative does not bind. This contrasts with GlcNAc-T I which cannot bind to the 4-deoxy-Man- substrate analogue. The data are compatible with our previous observations that a bisectingN-acetylglucosamine at the 4-OH position prevents both GlcNAc-T I and GlcNAc-T II catalysis. However, in the case of GlcNAc-T II, the bisectingN-acetylglucosamine prevents binding due to steric hindrance rather than to removal of an essential OH group. The 3-OH of the Man1-3 is an essential group for GlcNAc-T II since the 3-deoxy derivative does not bind to the enzyme. The trisaccharide GlcNAc1-2Man1-3Man-O-octyl is a good inhibitor (K
i=0.9mm). The above data together with previous studies indicate that binding of the GlcNAc1-2Man1-3Man- arm of the branched substrate to the enzyme is essential for catalysis.
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
13.
R. Gossrau 《Histochemistry and cell biology》1977,52(3):259-271
Zusammenfassung Verglichen mit 1- und 2-Naphthyl--d-glucosid,--d-galactosid,--d-glucuronid,--d-N-acetylglucosaminid,--d-glucosid,--d-galactosid und--d-mannosid werden 1- und 2-Naphthyl--l-fucosid schneller oder im gleichen Ausmaß von Homogenaten verschiedener Rattenorgane hydrolysiert. Trotzdem fällt der histochemische Nachweis der -l-Fucosidasen methodenunabhängig im Gegensatz zu dem der anderen Glykosidasen überwiegend negativ aus. Ursache dafür ist die massive Hemmung der -l-Fucosidase durch Aldehydfixation und Diazoniumsalze; die Inhibitionsrate liegt bei 90% bzw. zwischen 85 und 98%; die - und -d-Glucosidase, - und -d-Galactosidase, -d-Mannosidase, -d-Glucuronidase sowie -d-N-Acetylglucosaminidase werden durch Aldehydfixation oder Kuppler höchstens zu 70% gehemmt. Daher können 1- und 2-Naphthyl--l-fucosid für die histochemische Darstellung der -l-Fucosidase nicht einschränkungslos empfohlen werden. Kleine Mengen Dimethylformamid hemmen die meisten Glykosidasen nicht.Für biochemische Messungen der -l-Fucosidase eignet sich speziell 1-Naphthyl--l-fucosid und läßt sich an Stelle von p-Nitrophenyl--l-fucosid werwenden. Bei der fluorometrischen Untersuchung der -l-Fucosidase in Rattenorganen mit dem 2-Naphthylderivat ergeben sich bemerkenswerte Aktivitätsunterschiede.
Suitability of naphthyl--l-fucosides for the investigation of -l-fucosidases
Summary In comparison with 1- and 2-naphthyl -d-glucoside, -d-galactoside, -d-glucuronide, -d-N-acetylglucosaminide, -d-glucoside, -d-galactoside and -d-mannoside 1- and 2-naphthyl -l-fucoside are hydrolyzed more quickly or to the same extent by homogenates prepared from freezedried cryostate sections of various rat organs. Nevertheless, when the fucosides are employed for the histochemical demonstration of -l-fucosidase mostly negative data were obtained independent on the method used, whereas all other naphthyl glycosides deliver positive results. The reasons for these discrepancies are the marked inhibition of -l-fucosidase by aldehyde fixation and diazonium salts. Then, -l-fucosidase activity is suppressed to 90% and between 85 and 98% respectively; the inhibition of - and -d-glucosidase, - and -d-galactosidase, -d-mannosidase, -d-glucuronidase and -d-N-acetylglucosaminidase by the fixative or coupling reagent does not exceed 70%. Therefore 1- and 2-naphthyl -l-fucoside cannot be recommended in general for histochemical purposes. Small amounts of dimethylformamide do not influence the activity of most of the glycosidases investigated.For biochemical measurements, however, especially 1-naphthyl -l-fucoside represents a suitable alternative in a fluorometric procedure instead of p-nitrophenyl -l-fucoside used for the photometric evaluation of -l-fucosidase. With the fluorometric method the enzyme was measured in rat organs, which posses remarkably different activities of -l-fucosidase.相似文献
14.
Inka Brockhausen Folkert Reck William Kuhns Shaheer Khan Khushi L. Matta Ernst Meinjohanns Hans Paulsen Rajan N. Shah Michael A. Baker Harry Schachter 《Glycoconjugate journal》1995,12(3):371-379
UDP-GlcNAc:GlcNAc 1-2Man1-6R (GlcNAc to Man) 1,6-N-acetylglucosaminyltransferase V (GlcNAc-T V) adds a GlcNAc1-6 branch to bi- and triantennaryN-glycans. An increase in this activity has been associated with cellular transformation, metastasis and differentiation. We have used synthetic substrate analogues to study the substrate specificity and inhibition of the partially purified enzyme from hamster kidney and of extracts from hen oviduct membranes and acute myeloid leukaemia leukocytes. All compounds with the minimum structure GlcNAc1-2Man1-6Glc/Man-R were good substrates for GlcNAc-T V. The presence of structural elements other than the minimum trisaccharide structure affected GlcNAc-T V activity without being an absolute requirement for activity. Substrates with a biantennary structure were preferred over linear fragments of biantennary structures. Kinetic analysis showed that the 3-hydroxyl of the Man1-3 residue and the 4-hydroxyl of the Man- residue of the Man1-6(Man1-3)Man-RN-glycan core are not essential for catalysis but influence substrate binding. GlcNAc1-2(4,6-di-O-methyl-)Man1-6Glc-pnp was found to be an inhibitor of GlcNAc-T V from hamster kidney, hen oviduct microsomes and acute and chronic myeloid leukaemia leukocytes.Abbreviations all
allyl
- AML
acute myeloid leukaemia
- BSA
bovine serum albumin
- CML
chronic myelogenous leukaemia
- Gal
G,d-galactose
- Glc
d-glucose
- GlcNAc
Gn,N-acetyl-d-glucosamine
- HPLC
high performance liquid chromatography
- Man
M,d-mannose
- mco
8-methoxycarbonyl-octyl, (CH2)8COOCH3
- Me
methyl
- MES
2-(N-morpholino)ethanesulfonate
- oct
octyl
- pnp
p-nitrophenyl
- T
transferase 相似文献
15.
H. Schmalbruch 《Cell and tissue research》1968,85(3):343-349
Zusammenfassung Fasern der menschlichen Kehlkopfmuskulatur weisen seitliche Aussackungen auf, die unter dem Sarkolemm in lockerer Anordnung Kerne, Lysosomen, Lipofuscingranula und Mitochondrien mit oft konzentrisch angeordneten Cristae enthalten. Sie sind mit den lichtmikroskopisch bekannten End- bzw. Seitenkolben identisch. Diese Aussackungen werden von den gefäßnahen subsarkolemmalen Mitochondrienanhäufungen eines bestimmten, auch in der übrigen Skelettmuskulatur weitverbreiteten Muskelfasertyps abgeleitet. Es wurden keine Verbindungen mit Nervenfasern gefunden. Im Gegensatz zu Goerttler können wir diese Bildungen deshalb nicht als Mechanorezeptoren deuten. Die Endkolben werden als sekantial getroffene Seitenkolben aufgefaßt. Da die Aussackungen der Fasern auch bei gesunden jungen Männern in der Kehlkopfmuskulatur regelmäßig auftreten, handelt es sich hier nicht um eine krankhafte Bildung, wenn auch die Faser im Bereich der Aussackungen einen degenerativen Prozeß durchzumachen scheint.
Summary Fibers of human larynx muscles show lateral dilatations of the sarcolemma containing loosely disposed mitochondria, lysosomes and eventually one or more nuclei. The cristae of the mitochondria often are arranged concentrically. Corresponding fiber dilatations have already been described by light microscopists as side- resp. end-bulbs.Our electron-microscopical observations lead to the conclusion that the dilatations are derived from accumulations of mitochondria beneath the sarcolemma which in similar form — but smaller — are characteristic of one type of the different muscle fibers, frequently to be found in other muscles of the body. Both subsarcolemma accumulations of mitochondria are close to the muscle capillaries.The fiber dilatations have no connections with nerve axons, and therefore cannot be interpreted as mechanoreceptors (Goerttler, 1960). The end-bulbs are supposed to be secantially (or obliquely) cut side-bulbs. We do not consider them pathologic since they are regularly found in fibers of healthy young men. On the other hand, they may represent a circumscribed degenerative alteration the origin of which remains to be explored.相似文献
16.
A Gal1-4GlcNAc (2-6)-sialyltransferase from human liver was purified 34 340-fold with 18% yield by dye chromatography on Cibacron Blue F3GA and cation exchange FPLC. The enzyme preparation was free of other sialyltransferases. It did not contain CMP-NeuAc hydrolase, protease, or sialidase activity, and was stable at –20°C for at least eight months. The donor substrate specificity was examined with CMP-NeuAc analogues modified at C-5 or C-9 of theN-acetylneuraminic acid moiety. Affinity of the human enzyme for parent CMP-NeuAc and each CMP-NeuAc analogue was substantially higher than the corresponding Gal1-4GlcNAc (2-6)-sialyltransferase from rat liver.Abbreviations FPLC
fast protein liquid chromatography
- NeuAc
5-N-acetyl-d-neuraminic acid
- 9-amino-NeuAc
5-acetamido-9-amino-3,5,9-trideoxy-d-glycero-2-nonulosonic acid
- 9-acetamido-NeuAc
5,9-diacetamido-3,5,9-trideoxy-d-glycero--d-2-nonulosonic acid
- 9-benzamido-NeuAc
5-acetamido-9-benzamido-3,5,9-trideoxy-d-glycero--d-galacto-2-nonulosonic acid
- 9-fluoresceinyl-NeuAc
9-fluoresceinylthioureido-NeuAc
- 5-formyl-Neu
5-formyl--d-neuraminic acid
- 5-aminoacetyl-Neu
5-aminoacetyl--d-neuraminic acid
- CMP-NeuAc
cytidine-5-monophospho-N-acetylneuraminic acid
- GM1
Gal1-3GalNAc1-4(NeuAc2-3)Gal1-4Glc-ceramide
- ST
sialyltransferase
- DTE
1,4-dithioerythritol
Enzyme: Gal1-4GlcNAc (2-6)-sialyltransferase, EC 2.4.99.1. 相似文献
17.
Summary The specificity of induction of wooddegrading enzymes from Pullularia pullulans was investigated using series of mono-, di- and (14)--trisaccharides or glycanes. A strain of P. pullulans (1740), unable to grow on Avicel or carboxymethyl-cellulose (CMC), uses xylan and steamexploded wood as carbon sources. This strain, thus grown, was evaluated for various enzyme activities. d-Xylose was the nutritional inducer of -xylosidase and -xylanase. d-Glucuronic acid induced activity on CMC and -glucosidase activity was observed regardless of carbon source used. (14)--Xylobiose was not an inducer of -xylanase production, but high levels of this enzyme were obtained with either structural isomers (12) or (13)-. Since synthesis of this enzyme was stimulated by increasing xylose concentration yp to 40 g/l, it is suggested that xylose enters the cells by passive transport and is unable to induce a permease system.Affiliated to the Scientific, Technological and Medical University of Grenoble 相似文献
18.
Tibor Benedek 《Mycopathologia》1962,17(3):255-260
Summary
Castellani's water culture method for microscopic fungi was re-examined and confirmed in its every detail. It is an ideal method for, at least, the smaller culture collection, in order to avoid continuous, short term subculturing.
Benedek's suggestion for establishment of a mycotheca preserved in chlorallactophenol on the analogy of the herbarium of phanerogamists, may fill a long felt gap in mycological laboratories.
Zusammenfassung Castellani's Wasserkultur-methode für mikroskopische Pilze wurde einer Kontrolluntersuchung unterzogen. Sie konnte in all ihren Einzelheiten bestätigt werden. Sie ist eine ideale Methode, wenigstens für kleine Kultursammlungen, um eine fortgesetzte, kurz-fristige Überimpfung zu vermeiden. Benedek's Vorschlag für die Einrichtung einer Mykotheka in Chlorallactophenol in Analogie mit dem Herbarium für Blütenpflanzen, mag eine lang gefühlte Lücke im mykologischen Laboratorium beseitigen.
Résumé La méthode deCastellani, la culture en d'eau des champignons microscopiques, a été ré-examinée. Elle pouvait être confirmée en tous les détails. C'est une méthode idéale, au moins, pour la collection de cultures de petite dimension, pour éviter les transferts continus et d'intervalle courte.La suggestion deBenedek pour établir une mycothèque en chlorallactophénol, par analogie avec l' herbier pour les phanérogames peut remplir une lacune, existante pour long temps, aux laboratoires mycologiques.相似文献
19.
Bulk populations of T-cell receptor (Tcr) -expressing splenocytes from different inbred strains of mice were examined for the diversity of Tcr proteins. Immunoprecipitations with anti-C1/2, anti-C4, and anti-V1 sera demonstrated that splenocytes from B10.BR, C57BL/6, and C57L strains of mice expressed the same array of Tcr proteins, namely V1-C2, V1-C4, and V2-C1, although the Tcr heterodimers observed for each of these strains were biochemically distinct. Examination of bulk splenic Tcr heterodimers from several other inbred strains of mice demonstrated that each of the strains could be categorized into one of three basic phenotypes. For several reasons, the differences observed between the strains appeared to be solely dependent on polymorphisms of the Tcrg loci. First, F1 mice co-expressed both parental Tcr phenotypes. Second, the distinguishing polymorphism between mice of phenotype 1 and phenotypes 2 or 3 was due to the presence of an N-linked glycosylation site within the Tcrg-C1 gene segment, previously described for BALB.B and C57BL/6 Tcrg-C1 genes. Finally, the V1-C4 polymorphism between mice of phenotype 3 and phenotypes 1 or 2 was due to differences in core protein size. Furthermore, the three defined Tcr chains were expressed independently of the major histocompatibility complex (MHC) haplotype. Although no striking qualitative differences in Tcr heterodimers were observed between strains (including those with autoimmune disorders), a quantitative difference in the relative amount of C4-encoded proteins was observed on Tcr splenocytes from both newborn euthymic and adult athymic mice when compared to adult Tcr splenocytes from euthymic mice. These results demonstrate that genetic polymorphisms exist among different mouse strains and suggest that selective developmental pressures may govern Tcr expression.
Offprint requests to: J. A. Bluestone 相似文献
20.
Konrad Huppi Lawrence D'Hoostelaere Michael Kiefer Michael Steinmetz Evelyne Jouvin-Marche 《Immunogenetics》1986,24(5):304-308
We have examined the context of mouse T-cell receptor gamma (Tcr ) chain variable (V ) and constant (C) genes among a panel of geographically isolated species of mice. Our Southern hybridization survey with C reveals that essentially three C genes are found among mouse species extending phylogenetically from inbred mice through the feral species Mus pahari. However, a V DNA probe detects three to nine V restriction fragment bands among the same group of mice. These results suggest that certain feral mice such as M. pahari, M. platythrix, and M. shortridgei have amplified numbers of V genes. Studies of individual mice from these particular species indicate the highly amplified V content is not the result of a catastrophic gene duplication or deletion event. We conclude that certain species of mice maintain increased content of V presumably for increased diversity in a Tcell response. 相似文献