Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Flavonoids (103 species) were tested for inhibitory activity against influenza virus sialidase using sodium p-nitrophenyl-N-acetyl-alpha-D-neuraminate as substrate. 5,7,4'-Trihydroxy-8-methoxyflavone from the root of Scutellaria baicalensis showed the most potent activity (IC50, 55 microM), and this flavone appeared to be a non-competitive inhibitor of the enzyme. Whereas, negligible or weak inhibitory activities were observed for mouse liver sialidase, beta-galactosidase and alpha-mannosidase as tested. This flavone also inhibited the infection by influenza virus A/PR/8/34 of Madin-Darby canine kidney cells, and replication of the virus in the allantoic sack of embryonated egg. These results suggest that flavone, which has potent influenza virus sialidase inhibitory activity, may have anti-influenza virus activity.
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PMID:Inhibition of influenza virus sialidase and anti-influenza virus activity by plant flavonoids. 239 58

In the cell adhesion of aggregation-competent Dictyostelium cells, the requirement for the carbohydrate moiety of the glycoprotein appeared to be indirect in that it acts to protect the protein moiety from proteolytic degradation; however, the effect was limited to the tunicamycin (TM)-sensitive carbohydrate moiety (Hirano, T., et al. (1983) J. Biochem. 93, 1249-1257). In the present study, we showed that the EDTA-stable adhesion of aggregation-competent Dictyostelium cells was abolished by the treatment of intact cells with jack bean alpha-mannosidase, whereas neuraminidase, beta-galactosidase, beta-N-acetylhexosaminidase, or alpha-L-fucosidase had no effect. The EDTA-stable cohesiveness of TM-treated cells in the presence of leupeptin (TM/LP cells) was also abolished by the treatment of the cells with alpha-mannosidase. The effect of alpha-mannosidase was not prevented in the presence of LP. The N-glycoside-deficient contact site A (an adhesion-mediating glycoprotein) was obtained from TM/LP cells and was shown to have a molecular weight of 70,000. This protein (p 70) was shown to still have carbohydrates as detected by polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS) and subsequent staining of the gel with periodic acid-silver stain. Moreover, p 70 reacted with anti-gp 68, which has a specificity against alpha-mannosyl residues of carbohydrate chains. However, p 70 treated with alpha-mannosidase showed decreased reactivity with anti-gp 68. The monovalent antibody fragment of anti-contact site A or anti-p 70 inhibited EDTA-stable cell adhesion of both control and TM/LP cells. These results indicated that TM-resistant mannosyl residues of contact site A are directly involved in EDTA-stable adhesion of aggregation-competent cells. This is the first report of the direct involvement of the carbohydrate moiety in cell adhesion of aggregation-competent Dictyostelium cells. A schematic model is presented of the role of the carbohydrate moiety in EDTA-stable cell adhesion, including the direct effect of carbohydrates.
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PMID:Direct implication of surface mannosyl residues in cell adhesion of Dictyostelium discoideum. 241 9

Hypertonic NaCl administered to rats or mice has been demonstrated to induce in the liver a rapid disaggregation of polyribosomes and inhibition of protein synthesis. This study was concerned with whether hypertonic NaCl would affect nucleocytoplasmic translocation of RNA in the livers of rats. The effect of tube-feeding a hypertonic (10.7%) NaCl solution (321 mg in 3 ml/100 g body wt) for 10 minutes on in vitro release of 14C-orotate-labeled nuclear RNA was assayed. Although the combination of nuclei and cytosols of livers of hypertonic NaCl-treated rats revealed diminished in vitro labeled nuclear RNA release in comparison with hepatic nuclei and cytosols of control (water-treated) rats, each of the two components varied in activity. Even though the overall effect was an inhibitory one, cytosols of livers of hypertonic NaCl-treated rats stimulated in vitro release of labeled nuclear RNA, whereas nuclei of livers of hypertonic NaCl-treated rats revealed diminished in vitro release of labeled nuclear RNA in comparison with cytosols and nuclei of livers of control rats. The stimulatory effect of the hepatic cytosols of the hypertonic NaCl-treated rats was essentially unaffected by pretreatment of the rats with puromycin or cycloheximide, but was abolished by pretreatment of the cytosols in vitro with alpha-mannosidase or beta-galactosidase. Passage of cytosols of control and experimental livers through concanavalin A-agarose columns concentrated the activities of the eluates in stimulating in vitro labeled nuclear RNA release. In vivo 14C-orotate labeling of hepatic nuclear RNA for 30 minutes was increased by hypertonic NaCl treatment in comparison with water treatment of control animals. In vivo 14C-glucosamine incorporation into hepatic proteins of nuclei and nuclear envelopes was increased in hypertonic NaCl-treated rats in comparison with controls. In vitro 3H-tryptophan binding to proteins (trichloracetic acid-precipitable) to cytosols of livers of hypertonic NaCl-treated rats was increased in comparison with binding of controls. The results suggest that the administration of hypertonic NaCl rapidly leads to a change in hepatic cytosol whereby the activity to stimulate in vitro labeled nuclear RNA release is enhanced. This occurs without new protein synthesis, and the effect is probably mediated through a glycoprotein. In contrast, the hepatic nuclei of the rats treated with hypertonic NaCl show a decreased ability to release in vitro labeled nuclear RNA, possibly because of the development of a nuclear lesion.
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PMID:The influence of hypertonic NaCl on nucleocytoplasmic translocation of RNA in the rat liver. 242 14

The adhesiveness of a mucous strain of Pseudomonas aeruginosa to rabbit bladder mucosa has been investigated after pretreatment of the vesical mucosa with different glycosidases. Using a simple apparatus the study was carried out in parallel on samples of untreated and pre-treated mucosa. The results obtained showed that the cleavage of terminal sugar by addition of neuraminidase, N-acetyl-beta-D-glucosaminidase, alpha-mannosidase, alpha-L-fucosidase and beta-galactosidase produced a decrease in the number of adhered bacteria. A more drastic enzymatic action due to the combined effect of neuraminidase + alpha-L-fucosidase and neuraminidase + beta-galactosidase produced, on the other hand, an increased adhesion of bacteria, probably due to an unmasking of new receptor sites.
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PMID:Adhesiveness of Pseudomonas aeruginosa to rabbit vesical mucosa effect of glycosidases on cellular binding. 248 79

The role of N-acetylneuraminic acid and N-acetyl-D-glucosamine containing molecules in vesicular stomatitis virus-cell interaction was studied using specific lectins (limulin and wheat germ agglutinin) and esoglycosidases (neuraminidase, beta-galactosidase, alpha-mannosidase, alpha-fucosidase, beta-N-acetyl-D-glucosaminidase). Lectin treatment of vesicular stomatitis virus (VSV) indicated that carbohydrates of the VSV G envelope glycoprotein were not required for virus infectivity, whereas sialic acid appeared directly involved in the attachment of virus to erythrocytes. The comparative results obtained after enzymatic digestion of cell membrane carbohydrates or their cross linking by lectins demonstrated that whereas VSV infectivity was strongly reduced by pretreatment of chick embryo cells, virus binding to erythrocytes was unaffected by such treatments. We conclude that sugar residues may participate at the host cell attachment site which differs, at least in part, from the membrane binding site of erythrocytes.
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PMID:Involvement of carbohydrates in vesicular stomatitis virus-cell early interaction. 257 93

Adler and Martin (1983, Curr. Eye Res. 2, 359-66) found cathepsin D to be present in crude preparations of bovine interphotoreceptor matrix (IPM). The purpose of the present study was to determine, by investigating several acid hydrolases in purer IPM samples, whether hydrolytic enzymes abundant in RPE lysosomes were present also as normal components of the IPM. IPM was prepared from bovine eyes by the introduction of a small bleb of buffer between the neural retina and the RPE. These IPM samples were free from significant contamination by surrounding tissues; they contained IRBP as their only major protein, and had negligible amounts of lactate dehydrogenase and ROS-specific proteins. Most acid hydrolases were assayed fluorometrically by measuring the 4-methylumbelliferone released upon hydrolysis of appropriate derivatives; the substrate for cathepsin was hemoglobin. The amounts of the enzymes found in the IPM were far from uniform and could not be correlated with enzyme activities in either RPE or retina homogenates. The hydrolases in the IPM varied in amount from beta-galactosidase (28% of the RPE level), through N-acetyl-beta-glucosaminidase (20%), alpha-fucosidase (15%), beta-glucuronidase (12%), alpha-glucosidase (8%), cathepsin D (7%), alpha-mannosidase (7%), down to beta-glucosidase, acid phosphatase, and acid lipase (trace amounts, less than 1%). These results agree with the relative amounts of enzymes found by Wilcox (1987) to be secreted into the medium by cultured human RPE cells. Furthermore, the rank order of hydrolases in the IPM is the same as that for hydrolases secreted (but not recaptured) by human fibroblasts in I-cell disease. The conclusion from these correlations is that lysosomal enzymes are probably secreted, as a normal process, by the RPE into the IPM, where they may have a role in digesting shed outer segments and in catabolizing IPM components.
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PMID:Selective presence of acid hydrolases in the interphotoreceptor matrix. 261 85

In order to have an insight into the role of host lysosomal enzymes in the intracellular survival of Leishmania parasites, the activities of beta-galactosidase, alpha-mannosidase, and N-acetyl-beta-D-glucosaminidase were studied in peritoneal macrophages of hamsters infected with L. donovani. There was a significant decrease of all three lysosomal enzymes after infection. Heat-killed or formalin-treated parasites failed to inhibit the enzymes, instead a slight stimulation was observed. Purified excreted factor from promastigotes had no effect on the enzymes except beta-galactosidase which was inhibited up to 20%. Inhibition of enzymes was not due to increased secretion after infection. The absence of induction of any endogenous macrophage inhibitor was confirmed by mixed experiments. The levels of 5'-nucleotidase and lactate dehydrogenase remained unchanged after infection. Thus, the inhibition of lysosomal enzymes appears to be the effect of infection process and reflects to actua decrease rather than increased secretion or the action of any inhibitors present in Leishmania promastigotes.
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PMID:Suppression of macrophage lysosomal enzymes after Leishmania donovani infection. 271 50

Sites of binding of eight different lectins (LTA, UEA I, WGA, SBA, DBA, CON A, PNA, RCA I) to cat submandibular gland were studied after exposure of tissue sections to sialidase, alpha-fucosidase, beta-galactosidase, alpha-mannosidase, beta-N-acetylglucosaminidase. All lectins were affected by enzymatic predigestion and the labeling of individual lectins was highly dependent upon the glycosidase used to pretreat the sections. Glycoconjugates of demilunar, acinar and ductal cells exhibited a different composition of terminal sequences. For example, fucose proved to form the disaccharide fucose-galactose in demilunar and acinar cells, whereas it was present with the sequence fucose-N-acetyl-D-glucosamine in striated duct cells. Sialic acid participated both to the terminal sequence sialic acid-galactose and sialic acid-N-acetyl-D-galactosamine either in demilunar or in ductal cells. Lectin labeling combined with glycosidase digestion was also helpful in verifying the influence of neighbouring oligosaccharides on the affinity of lectins for the respective sugars.
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PMID:Enzymatic degradation and quantitative lectin labeling for characterizing glycoconjugates which act as lectin acceptors in cat submandibular gland. 271 45

Lamellar body hydrolases in acutely damaged and regenerating type II cells were determined using an established rat model with well-defined stages of bronchiolo-alveolar injury and repair. Lamellar bodies were isolated from control and ozone-exposed (3.0 ppm for 8 hours) adult male rats by sucrose density gradient centrifugation and analyzed for their content of six different lysosomal hydrolases. Immediately after 3 ppm ozone exposure (zero-time) there was a significant decrease in specific enzyme activity (units/mg protein) of five lamellar body hydrolases and these activities remained depressed for at least 24 hours after exposure. In addition, total enzyme activity (units/lung) was reduced at zero-time for beta-hexosaminidase and at 24 hours postexposure for alpha-mannosidase and alpha-L-fucosidase. During the reparative and recovery stages (48 to 96 hours) the hydrolases demonstrated variable elevations in both specific activity and total activity (units/lung). Characteristically, beta-hexosaminidase and beta-galactosidase reached supranormal values at 96 hours, whereas alpha-mannosidase remained below normal levels through the recovery stage. Moreover, at 24 to 48 hours the lamellar body fraction demonstrated prominent enzyme depletion relative to the expanding pool of stored surfactant. It is concluded that acute ozone stress initiates the development of hydrolase deficiency within the lamellar bodies of injured and regenerating type II cells. This deficiency state is followed by asynchronous lamellar body hydrolase elevations that reflect distinct patterns of response rather than uniform return to normal condition. The lysosomal enzyme changes of lamellar bodies may be pathogenetically linked to the development of associated alterations in the storage and secretion of surfactant.
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PMID:Sequential changes of lamellar body hydrolases during ozone-induced alveolar injury and repair. 271 79

Normal arterial foci which take up Evans blue dye (EBD) in vivo are believed to represent atherosclerosis-prone, hemodynamically stressed foci compared to areas which exclude dye. We have used the rabbit EBD model to examine focal aortic hydrolases of blue areas versus white areas, and we report herein significant focal variations of hydrolase activities. Enzymes measured included neutral alpha-glucosidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase, acid alpha-glucosidase, beta-galactosidase, beta-glucuronidase, cathepsin C, and acid cholesteryl esterase (ACE); specific activities were expressed on the basis of tissue DNA. In correlative areas of EBD uptake in normal rabbit aortic arch, ACE activity averaged 17% higher and cathepsin C activity averaged 37% lower than activities of areas free of EBD in the descending thoracic aorta (P less than 0.02). None of the glycosidases studied differed significantly between blue and white aortic areas. These findings indicate that discrete, intrinsic differences of hydrolytic enzyme activities exist in the normal rabbit aorta in areas delineated by in vivo EBD uptake, areas recognized as lesion-prone vs lesion-resistant.
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PMID:Intrinsic focal variations of rabbit aortic hydrolase activities. 276 19


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