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)

Sialidase isolated from human placenta is associated with several proteins including acid beta-galactosidase, carboxypeptidase, N-acetyl-alpha-galactosaminidase, and others. These proteins are thought to form an aggregated complex during isolation of sialidase. One of the proteins of 60 kDa was recently identified by Potier et al. (Biochem. Biophys. Res. Comm. 173, 449-456, 1990) as a sialidase protein: this protein also cross-reacted with anti-prosaposin antibodies. We have isolated this protein and from the following evidence identified it as a heavy chain component of immunoglobulin G and not sialidase or a derivative of prosaposin. On gel filtration HPLC, sialidase activity and the 60 kDa protein were clearly separated from one another. The 60 kDa protein cross-reacted not only with antibodies raised against human saposins A, C, and D, but also with second antibody (goat anti-rabbit immunoglobulin G antibody) alone. This 60 kDa protein strongly cross-reacted with anti-human immunoglobulin G antibodies. The sequence of the initial 15 amino acids from the N-terminus of the 60 kDa protein was identical to the sequence of an immunoglobulin G heavy chain protein Tie (gamma 1).
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PMID:Human placental sialidase complex: characterization of the 60 kDa protein that cross-reacts with anti-saposin antibodies. 190 36

Maternal protein deficiency imposed on rats a month prior to conception, and during gestation and lactation, resulted in a significant cell loss in cerebrum, cerebellum, brain stem and spinal cord of pups at weaning. The cerebellum was the most affected central nervous system (CNS) region; it contained only 25% of the normal cell number. Undernourished pups were also found to have a lower concentration of total gangliosides in cerebrum as compared to that of controls. However, the total ganglioside concentration was unaffected in the cerebellum, brain stem and spinal cord by maternal undernutrition. In all regions, undernutrition caused significant changes in the proportions of individual gangliosides; these alterations were region-specific. Sialidase, beta-galactosidase, beta-glucosidase, and beta-hexosaminidase, which are involved in the catabolism of gangliosides, showed higher activities in all the regions of undernourished pups, suggesting that these enzymes may play a role in maintaining the porportions of various ganglioside fractions.
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PMID:Maternal protein deficiency in rat: effects on central nervous system gangliosides and their catabolizing enzymes in the offspring. 194 99

An increased resistance of laboratory animals to pulmonary infections following per os administration of a glyco-proteic complex extracted from Klebsiella pneumoniae has been reported. This was associated with an increased phagocytic capacity of alveolar macrophages (AM). In this report, the effect of treating guinea pigs with this extract on the alveolar macrophage (AM) glycosidase machinery has been studied. AM were collected by bronchoalveolar lavage, the cells were pelleted by centrifugation and AM were purified by adherence on plastic dishes. Sialidase, beta-galactosidase, beta-glucuronidase and N-acetyl-beta-D glucosaminidase activities were measured in the AM homogenate. In order to evaluate an extracellular release of these enzymes, they were also assayed in the cell free lavage fluid. Lactic dehydrogenase (LDH) activity was assayed as a control for cell lysis. In treated animals, the total number of cells as well as the number of AM increased by 25% (ns). The protein concentration was slightly reduced in the cell homogenate and unchanged in the lavage fluid. The only significant change was a decreased sialidase activity, in AM homogenate (p less than or equal to 0.01) and in lavage fluids (ns). The LDH activity was not increased in the lavage fluids.
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PMID:Glycosidase activities in alveolar macrophages from guinea pigs stimulated with a glyco-proteic complex extracted from Klebsiella pneumoniae. 212 66

Sialidase activity was assayed in homogenized rabbit alveolar macrophages using a fluorogenic substrate: sodium 4-methylumbelliferyl-alpha-D-neuraminate. After differential centrifugation one acid-active enzyme (optimum pH 4.2) was detected in the 16,000 X g pellet that contained lysosomes, mitochondria and peroxisomes. A second activity, with an optimum pH of 5.4, was found in the cytosolic fraction. The acid-active sialidase accounted for more than 95% of the total sialidase activity in crude homogenate. When alveolar macrophages were collected from rabbits stimulated with bacillus Calmette-Guerin (BCG), the acid-active sialidase specific activity was increased 2.5-fold whereas other lysosomal enzymes such as N-acetylglucosaminidase and beta-galactosidase were stable. The cytosolic sialidase activity did not change.
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PMID:Lysosomal and cytosolic sialidases in rabbit alveolar macrophages: demonstration of increased lysosomal activity after in vivo activation with bacillus Calmette-Guerin. 354 51

We analyzed the subcellular localization of sialidases in human lymphocytes from a patient with adult type sialidosis with partial beta-galactosidase deficiency and normal controls. Sialidase activities were measured with alpha,2 leads to 3 NeuAc-lactitol, 4-methylumbelliferyl-NeuAc and GM3 ganglioside as substrates. Sialidases in the lysosomes were sonication-labile and hydrolyzed mainly hydrophilic substrates such as NeuAc-lactitol and 4-methylumbelliferyl-NeuAc, but hydrolyzed subsidiarily GM3 ganglioside. On the other hand, sialidases in the plasma membrane were sonication-stable and hydrolyzed both hydrophilic substrates and GM3 ganglioside. In sialidosis with partial beta-galactosidase deficiency, the sialidases of the lysosomes showed 3-5% activity toward hydrophilic substrates and 25% activity toward GM3 ganglioside as compared with sialidase activities of the controls. However, there are no differences in the activities of the sialidases in the plasma membrane. These results demonstrate that the essential defect in this disease is the deficiency of a lysosomal sialidase.
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PMID:Lysosomal sialidase deficiency in sialidosis with partial beta-galactosidase deficiency. 640 33

Two forms of alkaline phosphatase (orthophosphoric monoester phosphohydrolase (alkaline optimum, EC 3.1.3.1) have been purified from human small intestine by column chromatography on DEAE-cellulose and tyraminyl derivative affinity gel, and by preparative disc gel electrophoresis. Intestinal phosphatases were electrophoretically separated into two components, fast- and slow-moving enzymes, with apparent molecular weights of 140000 and 168000 and with subunit weights of 68000 and 80000, respectively. Analyses of carbohydrate and amino acid revealed marked differences in the two enzymes. Enzymatic properties and affinities for an anti-blood group antibody were also found to differ. Papain digestion released a hydrophobic small peptide from the slow-moving enzyme and its enzymatic properties resembled those of the fast-moving enzyme. Circulating clearance (T1/2) of the slow- and fast-moving enzymes from adult intestine was found to be 7.5 h and 1.3 h, respectively; that of fetal intestinal enzyme was 2.8 h. Sialidase, sialidase/beta-galactosidase, or sialidase/beta-galactosidase/N-acetyl-beta-glucosaminidase treatment of the fetal enzyme reduced the value to about 40 min. Further, digestion with alpha-fucosidase, alpha-mannosidase or both restored it to nearly the original level. Organ distribution of injected 125I-labelled enzymes indicates that the desialylated hepatic enzyme was selectively distributed in liver, while the degalactosylated intestinal enzyme was incorporated into liver lymph fluid, and small intestine. These results suggest that the pathway of circulating clearance of alkaline phosphatase has several routes.
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PMID:Multiple forms of human intestinal alkaline phosphatase: chemical and enzymatic properties, and circulating clearances of the fast- and slow-moving enzymes. 730 75

Sialidase [E.C.3.2.1.18] has previously been purified from porcine liver by procedures including extraction, ammonium sulfate precipitation, concanavalin A-Sepharose adsorption, activation, CM-Sepharose ion exchange chromatography, and HPLC on a Shim pack Diol 300 column. Two sialidase preparations, sialidase I and II, were obtained by CM-Sepharose column chromatography and were eluted with pH 4.5 and 5.0 buffers, respectively. The two enzyme preparations showed the same optimum pH, pH stability, and specificities for natural substrates. The two final preparations contained beta-galactosidase activity and showed three protein components of 64, 30, and 21 kDa with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which are derived from the beta-galactosidase multimer. The anti-beta-galactosidase multimer antiserum was able to precipitate sialidase activity. It is likely that porcine liver sialidase exists as a multienzyme complex with beta-galactosidase and carboxypeptidase (protective protein).
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PMID:Purification and characterization of sialidase from porcine liver. 970 49

Viridans streptococci have emerged as major opportunistic pathogens. We suggest that for these bacteria to proliferate in vivo and cause disease, they must utilize host tissue components. We have therefore examined the ability of all recognized species of viridans streptococci to liberate and utilize the constituent sugars of the glycans of the extensively sialylated human serum alpha1-acid glycoprotein (AGP) as the sole source of carbohydrate to support in vitro growth. Analysis of residual glycans following bacterial growth was performed by high-pH anion exchange chromatography with pulsed amperometric detection and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Only those species which produced sialidase-namely, Streptococcus oralis, S. intermedius, and S. defectivus--grew on AGP. The extent of degradation of glycans was dependent on the particular glycosidases produced by the bacteria. S. defectivus produced only a sialidase which released the terminal N-acetylneuraminic acid residues of the glycans, and the liberated sugar was utilized. S. intermedius also produced beta-galactosidase and beta-N-acetylglucosaminidase, which removed galactose and N-acetylglucosamine from desialylated glycans, all of which again were utilized by the organism. S. oralis produced beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-fucosidase and novel alpha- and beta-mannosidases which were apparent only from the analysis of the residual sugars of AGP. S. oralis cleaved all the sugars from AGP except for 22% of the N-acetylglucosamine. The residual N-acetylglucosamine residues remaining were those linked to the asparagine of the peptide backbone. All the monosaccharides released by S. oralis from AGP, with the exception of fucose, were utilized. Sialidase production may be a key factor for growth of these species of viridans streptococci on glycoproteins in vivo, since they are commonly associated with extra-oral diseases, with S. oralis emerging as an important pathogen.
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PMID:Growth of Viridans streptococci on human serum alpha1-acid glycoprotein. 1040 65

Sialidases are enzymes that influence cellular activity by removing terminal sialic acid from glycolipids and glycoproteins. Four genetically distinct sialidases have been identified in mammalian cells. In this study, we demonstrate that three of these sialidases, lysosomal Neu1 and Neu4 and plasma membrane-associated Neu3, are expressed in human monocytes. When measured using the artificial substrate 2'-(4-methylumbelliferyl)-alpha-d-N-acetylneuraminic acid (4-MU-NANA), sialidase activity of monocytes increased up to 14-fold per milligram of total protein after cells had differentiated into macrophages. In these same cells, the specific activity of other cellular proteins (e.g. beta-galactosidase, cathepsin A and alkaline phosphatase) increased only two- to fourfold during differentiation of monocytes. Sialidase activity measured with 4-MU-NANA resulted from increased expression of Neu1, as removal of Neu1 from the cell lysate by immunoprecipitation eliminated more than 99% of detectable sialidase activity. When exogenous mixed bovine gangliosides were used as substrates, there was a twofold increase in sialidase activity per milligram of total protein in monocyte-derived macrophages in comparison to monocytes. The increased activity measured with mixed gangliosides was not affected by removal of Neu1, suggesting that the expression of a sialidase other than Neu1 was present in macrophages. The amount of Neu1 and Neu3 RNAs detected by real time RT-PCR increased as monocytes differentiated into macrophages, whereas the amount of Neu4 RNA decreased. No RNA encoding the cytosolic sialidase (Neu2) was detected in monocytes or macrophages. Western blot analysis using specific antibodies showed that the amount of Neu1 and Neu3 proteins increased during monocyte differentiation. Thus, the differentiation of monocytes into macrophages is associated with regulation of the expression of at least three distinct cellular sialidases, with specific up-regulation of the enzyme activity of only Neu1.
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PMID:Differential expression of endogenous sialidases of human monocytes during cellular differentiation into macrophages. 1588 3

We have previously demonstrated that Chinese hamster ovary (CHO) cell lysates harbor sialidase, beta-galactosidase, beta-hexosaminidase, and fucosidase activities that can accumulate extracellularly in CHO cell culture, thereby potentially leading to extracellular modification of glycoprotein oligosaccharides. The sialidase activity in CHO cell lysates was surprisingly active and stable at pH 7.5, with a half-life of 57 h at 37 degrees C.We have extended this work to determine whether 293, NS0, or hybridoma cell lysates contain similar glycosidase activities. The pH-activity profiles of beta-galactosidase and beta-hexosaminidase in lysates of these three cell lines resemble the pH-activity profiles for these enzymes in CHO cell lysate, whereas the pH-activity profiles of sialidase and fucosidase appear to be cell-type dependent. Sialidase activities were relatively stable at pH 4.5 in 293, NS0, and hybridoma cell lysates. However, the activities in 293 and NS0 cell lysates were unstable at pH 7.5, with no activity remaining after a 2-h incubation at 37 degrees C. The sialidase activity in hybridoma cell lysate was moderately stable at pH 7.5 with 30% of the activity remaining after a 2-h incubation at 37 degrees C. We conclude that the sialidase activites from 293, NS0, and hybridoma cells have characteristics similar to the vast majority of reported mammalian sialidase activities, and that these activities are markedly differant from the CHO cell sialidase activity.Finally, sialidase, beta-galactosidase, beta-hexosaminidase, and fucosidase activities were measured at pH 7 in cell-free bioreactor supernatants of the hybridoma cell line. As previously observed in CHO cell culture, all four glycosidase activities were present in the hybridoma supernatants. However, the sialidase activity in hybridoma supernatant was an order of magnitude lower than in CHO cell culture supernatant despite the fact that the hybridoma cell lysis rate was an order of magnitude higher. (c) 1994 John Wiley & Sons, Inc.
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PMID:Glycosidase activities of the 293 and NS0 cell lines, and of an antibody-producing hybridoma cell line. 1861 25


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