Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sialic acid-containing storage material was isolated from cultured human galactosialidosis fibroblasts, by a combination of gel filtration and anion-exchange chromatography on Mono Q. The obtained sialyloligosaccharides were analyzed by 500-MHz 1H-NMR spectroscopy in combination with sugar analysis and analytical HPLC. The storage material consisted of a series of completely sialylated N-acetyl-lactosamine type of structures having Man beta 1-4GlcNAc at the reducing terminus in common, similar to those recently reported for human sialidosis fibroblasts. Comparison of the storage material from both sources revealed only differences in their relative amounts. In control fibroblasts these compounds could not be detected. The nature of the accumulated compounds is in accordance with the alpha-neuraminidase deficiency in both genetic diseases. The additional deficiency of beta-galactosidase in case of galactosialidosis is not reflected in the storage material.
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PMID:A comparative study of the accumulated sialic acid-containing oligosaccharides from cultured human galactosialidosis and sialidosis fibroblasts. 313 48

A sialylhexasaccharide fraction (S-5) of human milk was obtained as described by A. Kobata and V. Ginsburg [(1972) Arch. Biochem. Biophys. 150, 273-281] and labeled by reduction with NaB[3H]4. When subjected to affinity chromatography on immobilized wheat germ agglutinin (WGA), a single component representing 60% of the S-5 fraction was retarded by the column. The asialo derivative of the WGA-retarded oligosaccharide had a higher affinity for the WGA column than the native sialyloligosaccharide. The neutral hexaose was identified as lacto-N-neohexaose by sequential exoglycosidase digestions in combination with gel filtration analyses of digestion products. Enzymatic removal of the nonsialylated branch of the intact sialyloligosaccharide by jack bean beta-galactosidase and beta-N-acetylhexosaminidase resulted in a single sialyl[3H]tetraose which was identified as sialyltetrasaccharide c (NeuAc alpha 2-6Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4GlcO[3H]) by cochromatography with authentic standard and specific antibody binding. Independent evidence for the structure of the sialylhexasaccharide was obtained by 500-MHz1H NMR spectroscopy of the WGA-purified oligosaccharide before and after neuraminidase digestion. The structural data are consistent with the following, previously undescribed, sialylhexaose in human milk: (formula; see text).
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PMID:A novel sialylhexasaccharide from human milk: purification by affinity chromatography on immobilized wheat germ agglutinin. 319 33

We describe the structures of two positional isomers of sialylheptasaccharide isolated from the urine of a patient with sialidosis with partial deficiency of beta-galactosidase. Based on structural studies including compositional sugar analysis, exoglycosidase digestion, chemical ionization mass spectrometry, proton nuclear magnetic resonance spectrometry, and methylation analysis, their structures were deduced to be as follows: AcNeu alpha 2----6Gal beta 1----4GlcNac beta 1----2Man alpha 1----3(Man alpha 1----6)Man beta 1----4GlcNac; AcNeu alpha 2----6Gal beta 1----4GlcNac beta 1----2Man alpha 1----6(Man alpha 1----3)Man beta 1----4GlcNac. Sialyloligosaccharide 1 has previously been found in the urine and liver of patients with mucolipidosis I and II and sialidosis, but sialyloligosaccharide 2 has not been found yet in human urine. These two sialyloligosaccharides could not be completely separated by any chromatographic procedures tested. The analytical techniques, including methylation study and NMR spectroscopy, could not clearly detect the differences between them. However, alpha-mannosidase treatment gave important information for the structural analyses of these sialyloligosaccharides.
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PMID:Two positional isomers of sialylheptasaccharides isolated from the urine of a patient with sialidosis. 393 47

The kinetics for imino hydrogen exchange, at individual base pairs in the DNA sequence corresponding to the lactose operon operator of Escherichia coli, has been examined by NMR saturation recovery measurements as a function of temperature. Three 17-base-pair subsections of the lac operator DNA were chemically synthesized for these studies. The results support our previous observations in the 36-base-pair complete lac operator DNA fragment that has been used in our previous NMR studies. The results indicate faster opening kinetics at a GTG/CAC that is also the site of operator mutations leading to the highest level of constitutive beta-galactosidase synthesis. The GTG/CAC sequence occurs frequently and often symmetrically in prokaryotic and eukaryotic DNA sites where one anticipates specific protein interaction for gene regulation or recombination.
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PMID:Correlation of lac operator DNA imino proton exchange kinetics with its function. 632 23

Various bacterial strains have been exposed to a homogeneous magnetic field of 1 Tesla and to the conditions found in an NMR imaging experiment of the type used in a recent abdominal scan (Mansfield et al., 1978). No mutagenic or lethal effects were observed. The activity of the bacterial enzyme beta-galactosidase was also found to be independent of the applied magnetic field.
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PMID:The effects of NMR exposure on living organisms. I. A microbial assay. 645 75

The conformations of nitrogen-in-the-ring sugars and their N-alkyl derivatives were studied from 1H NMR analyses, mainly using 3J(H,H) coupling constants and quantitative NOE experiments. No significant difference was seen in the ring conformation of 1-deoxynojirimycin (1), N-methyl-1-deoxynojirimycin (2), and N-butyl-1-deoxynojirimycin (3). However, it was shown that the C6 OH group in 1 is predominantly equatorial to the piperidine ring, while that in 2 or 3 is predominantly axial, and its N-alkyl group is oriented equatorially. In the furanose analogues 1,4-dideoxy-1,4-imino-D-arabinitol (4) and its N-methyl (5) and N-butyl (6) derivatives, the five-membered ring conformation differed significantly by the presence or absence of the N-substituted group and the length of the N-alkyl chain. Compound 3 reduced its inhibitory effect on almost all glycosidases, resulting in an extremely specific inhibitor for processing alpha-glucosidase I since N-alkylation of 1 is known to enhance both the potency and specificity of this enzyme in vitro and in vivo. This preferred (C6 OH axial) conformation in 2 and 3 appears to be responsible for their strong alpha-glucosidase I activity. Compound 4 is a good inhibitor of intestinal alpha-glucohydrolases, alpha-glucosidase II, and Golgi alpha-mannosidases I and II, but its N-alkyl derivatives 5 and 6 markedly decreased inhibitory potential for all enzymes tested. In the case of 2,5-dideoxy-2,5-imino-D-mannitol (DMDP, 7), which is a potent beta-galactosidase inhibitor, its N-methyl (8) and N-butyl (9) derivatives completely lost potency toward beta-galactosidase as well. N-Alkylation of compounds 4 and 7, known well as potent yeast alpha-glucosidase inhibitors, resulted in a serious loss of inhibitory activity toward yeast alpha-glucohydrolases. Activity of these nine analogues against HIV-1 replication was determined, based on the inhibition of virus-induced cytopathogenicity in MT-4 and MOLT-4 cells. Compounds 2 and 3, which are better inhibitors of alpha-glucosidase I than 1, proved active with EC50 values of 69 and 49 micrograms/mL in MT-4 cells and 100 and 37 micrograms/mL in MOLT-4 cells, respectively, while none of the furanose analogues exhibited any inhibitory effects on HIV-1. The change in potency and specificity of bioactivity by N-alkylation of nitrogen-in-the-ring sugars appears to be correlated with their conformational change.
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PMID:N-alkylated nitrogen-in-the-ring sugars: conformational basis of inhibition of glycosidases and HIV-1 replication. 760 1

Eleven oligosaccharides formed by a transglycosylation reaction during lactose hydrolysis with Bacillus circulans beta-galactosidase were purified by gel permeation chromatography, charcoal chromatography, and HPLC. From the results of methylation analysis, and MS and NMR studies, it was concluded that these oligosaccharides were beta-D-Galp-(1-->3)-D-Glc, beta-D-Galp-(1-->6)-D-Glc, beta-D-Galp-(1-->2)-D-Glc, beta-D-Galp-(1-->4)-beta-D-Galp-(1-->4)-D-Glc, beta-D-Galp-(1-->6)-[beta-D-Galp-(1-->2)]-D-Glc, beta-D-Galp-(1-->6)-[beta-D-Galp-(1-->4)]-D-Glc, beta-D-Galp-(1-->4)-beta-D-Galp-(1-->3)-D-Glc, beta-D-Galp-(1-->4)-beta-D-Galp-(1-->2)-D-Glc, beta-D-Galp-(1-->4)-[beta-D-Galp-(1-->2)]-D-Glc, beta-D-Galp-(1-->4)-beta-D-Galp-(1-->6)-D-Glc, beta-D-Galp-(1-->6)[beta-D-Galp-(1-->3)]-D-Glc. The last five are newly observed oligosaccharides. The results of a use test (in vitro) by human intestinal bacteria showed that the oligosaccharides containing lactose units were predominantly used by human intestinal bifidobacteria.
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PMID:Formation of oligosaccharides from lactose by Bacillus circulans beta-galactosidase. 761 88

Five calystegins were extracted from the roots of Physalis alkekengi var. francheti (Solanaceae) with hot water and purified to homogeneity by the combination of a variety of ion-exchange column chromatographies. Their structures have been determined from the 1H- and 13C-NMR spectral data, and two of the compounds were identified as calystegins A3 and B2, which have been isolated from the roots of Calystegia sepium (Convolvulaceae). Two of the remaining three were found to be 1 alpha, 3 alpha, 4 beta-trihydroxy-nor-tropane and 1 alpha, 2 alpha, 3 alpha, 4 beta-tetrahydroxy-nor-tropane and given the trivial name calystegins A5 and B3, respectively. The last calystegin was assigned as 1 alpha, 2 beta, 3 alpha, 6 alpha-tetrahydroxy-nor-tropane, which was the same as the relative configuration proposed in the literature for calystegin B1 isolated from C. sepium. However, the 13C-NMR spectral data for the compound from C. sepium differed substantially from our results. From a personal communication with the authors of the original paper on calystegins, it was clarified that the 13C-NMR chemical shifts of calystegin B1 in the original paper had been erroneous. Since their corrected 13C-NMR data of calystegin B1 and its 1H-NMR chemical shifts in the original paper are very close to our present data, we concluded that both compounds from C. sepium and P. alkekengi are identical. Calystegin B2 has been known to be a potent competitive inhibitor of almond beta-glucosidase (Ki = 1.2 microM) and coffee bean alpha-galactosidase (Ki = 0.86 microM). In this study calystegin B1 (1 alpha, 2 beta, 3 alpha, 6 alpha-tetrahydroxy-nor-tropane) proved to be a potent competitive inhibitor of almond beta-glucosidase (Ki = 1.9 microM) and bovine liver beta-galactosidase (Ki = 1.6 microM), but not an inhibitor of alpha-galactosidases. Calystegin A3 was found to be a weaker inhibitor compared to calystegin B2 but with the same inhibitory spectrum. Calystegin A5, a 2-deoxy derivative of calystegin B2, showed no activity against any glycosidases tested. Since calystegin B3, a 2-epimer of calystegin B2, also exhibited only a weak inhibitory activity, it was concluded that the equatorially oriented OH group at C2 is the essential feature for recognition and strong binding by the active site of glycosidases.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Calystegins of Physalis alkekengi var. francheti (Solanaceae). Structure determination and their glycosidase inhibitory activities. 774 59

A combination of commercially available preparations of Aspergillus niger beta-D-galactosidase, endo-alpha-L-arabinanase, alpha-L-arabinosidase, and endo-beta-D-galactanase has been used to generate oligoglycosyl fragments of the backbone of rhamnogalacturonan I (RG-I) that had been isolated from the walls of suspension-cultured sycamore cells. The backbone-cleaving enzyme, which is present in the beta-D-galactosidase preparation, only fragments the RG-I backbone when many of the neutral oligoglycosyl side chains have been removed by the other exo- and endo- glycanases. The oligosaccharides released from the backbone were separated from the partially fragmented RG-I and then purified, as their oligoglycosyl aldonic acids, by HPAEC-PAD. Those backbone fragments with degrees of polymerization (dp's) between 2 and 11 were characterized using one- and two-dimensional 1H NMR spectroscopy, electrospray mass spectrometry, and glycosyl-residue and glycosyl-linkage composition analyses. Two series of oligoglycosyl fragments were identified. The quantitatively predominant series has the structure alpha-D-GalpA-(1 --> 2)- alpha-L-Rhap-[ --> 4)-alpha-D-GalpA-(1 --> 2)-alpha-L-Rhap-(1 --> ]n-4-D-GalpA, and the quantitatively minor series has the structure alpha-L-Rhap-[ --> 4)-alpha-D-GalpA-(1 --> 2)-alpha-L-Rhap-(1 --> ]n-4-D- GalpA (n = 1-5). Thus, the enzyme preparations contain an alpha-L-rhamnosidase in addition to the endo- rhamnogalacturonase. The products of the endo-rhamnogalacturonase provide additional evidence that the backbone of RG-I is composed of the diglycosyl repeating unit: --> 4)-alpha-D-GalpA-(1 --> 2)-alpha-L-Rhap- (1 -->. The endo-rhamnogalacturonase from the A. niger beta-D-galactosidase preparation and the endo- rhamnogalacturonase secreted by Aspergillus aculeatus [H.A. Schols et al. Carbohydr. Res., 206 (1990) 117-129] have the same substrate specificities and generate similar oligoglycosyl fragments.
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PMID:Isolation and structural characterization of endo-rhamnogalacturonase-generated fragments of the backbone of rhamnogalacturonan I. 800 Oct 21

Biosynthesis and intracellular transport of recombinant human full-length beta 1,4 galactosyltransferase (GT) and full-length alpha 2,6 sialyltransferase (ST) were investigated in Saccharomyces cerevisiae. Recently, enzymic activity of recombinant GT (rGT) in crude homogenates of S. cerevisiae could successfully be demonstrated [Krezdorn, C., Watzele, G., Kleene, R. B., Ivanov, S. X. & Berger, E. G. (1993) Eur. J. Biochem. 212, 113-120]. In the present work, we show that, in yeast strains transformed with plasmid pDPSIA containing the cDNA coding for human ST, rST enzymic activity using asialo-fetuin or N-acetyllactosamine as acceptor substrates could readily be detected. Analysis by 1H-NMR spectroscopy of the disaccharide product of rGT, as recently reported, and the trisaccharide product of rST demonstrated that only the expected glycosidic linkages were formed. Following mechanical disruption of yeast cells, both enzymes sedimented with a fraction enriched in membranes of the endoplasmic reticulum (ER) and were activated by Triton X-100 3-5-fold. rGT and rST could be immunoprecipitated from their [35S]Met-labelled transformed yeast extracts using polyclonal antibodies raised against fusion proteins consisting of beta-galactosidase-GT or beta-galactosidase-ST, respectively, expressed in Escherichia coli. For rGT a single glycosylated form of apparent molecular mass 48 kDa was reported, but for rST two main bands corresponding to apparent molecular masses of 48 kDa and 44 kDa, respectively, were detected. Immunoprecipitation from either tunicamycin-treated [35S]Met-labelled transformed yeast cells or labelling with radio-active sugars both indicated that the 44-kDa form of rST was non-glycosylated and that the 48-kDa form of rST was core N-glycosylated. In addition, core glycosylation of both recombinant enzymes demonstrated that they were competent for translocation across the ER membranes. However, the 44-kDa form of rST was converted to the 48-kDa glycosylated form only slowly, suggesting a mechanism of posttranslational translocation. Absence of hyperglycosylation of rST and rGT in wild type and lack of the Golgi-specific man-alpha 1,6-man epitope suggest that the recombinant enzymes did not enter the yeast Golgi apparatus. These results indicated that both rGT and rST are retained as enzymically active enzymes in the ER of yeast and suggest a ribonucleoprotein-independent import of rST into the ER.
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PMID:Human beta 1,4 galactosyltransferase and alpha 2,6 sialyltransferase expressed in Saccharomyces cerevisiae are retained as active enzymes in the endoplasmic reticulum. 814 35


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