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)

A new type of agarose material, superporous agarose, was used as a support material in an analytical system designed for monitoring of bioprocesses with respect to metabolites and intracellular enzymes. The superporous agarose was used in the form of miniaturised gel plug columns (15 x 5.0 mM I.D. monolithic gel bed). The gel plugs were designed to have one set of very large pores (about 50 microm in diameter) through which cells, cell debris and other particulate contaminants from the bioreactor could easily pass. The material also had normal diffusion pores (300 A) characteristic of all agarose materials, providing ample surface for covalent attachment of antibodies and enzymes used in the analytical sequence. The superporous agarose gel plug columns were characterised with respect to flow properties and handling of heavy cell loads as well as dispersion of injected samples (a Bodenstein number of about 40 was observed with acetone tracer at a flow rate of 1 ml min(-1)). To evaluate the practical performance of the superporous gel plug columns, two applications were studied: (1) on-line determination of glucose in cultivation broth (gel plug with immobilized glucose oxidase) and (2) immunochemical quantification of intracellular beta-galactosidase in E. coli (gel plug with lysozyme to achieve cell lysis and gel plug with antibodies against beta-galactosidase).
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PMID:Superporous agarose monoliths as mini-reactors in flow injection systems. On-line monitoring of metabolites and intracellular enzymes in microbial cultivation processes. 1132 17

Coimmobilization of beta-galactosidase and glucose oxidase in a redox polymer, polyvinylferrocenium perchlorate (PVF+ ClO4-), led to the development of an enzyme electrode for the determination of lactose. The amperometric response of the electrode was measured at +0.70 V vs. SCE, which was due to the electrooxidation of enzymatically produced H2O2. The effects of the substrate and buffer concentrations as well as the pH on the electrode response were elucidated.
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PMID:A novel two-enzyme amperometric electrode for lactose determination. 1187 16

A microdialysis-coupled flow injection amperometric Sensor (microFIAS) was used to determine glucose, galactose, and lactose in milk. The sensor is based on enzyme-catalyzed reaction in combination with the three well-established analytical techniques, namely; microdialysis sampling, flow injection analysis (FIA), and amperometric detection. With the multianalyte sensor it was possible to detect glucose and galactose by sequential injection of their corresponding oxidase enzymes: glucose oxidase and galactose oxidase, while lactose was determined by injection of a mixture of beta-galactosidase and glucose oxidase enzymes. The sensor showed a linear response between 0.05 and 10 mM for glucose, between 0.1 and 20 mM for galactose and between 0.2 and 20 mM for lactose, respectively. The relative standard deviation values of the sensor measurements for glucose, galactose, and lactose were 3-4% (n = 3). The sensor measurements for lactose content in milk were compared with a standard method with an infrared spectrophotometer.
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PMID:Detection of glucose, galactose, and lactose in milk with a microdialysis-coupled flow injection amperometric sensor. 1214 64

We have developed an antibody fusion protein (anti-rat TfR IgG3-Av) with the ability to deliver different molecules into cancer cells. It consists of avidin genetically fused to the C(H)3 region of a human IgG3 specific for the rat transferrin receptor. It forms strong, noncovalent interactions with biotinylated molecules such as glucose oxidase and beta-galactosidase, and delivers them into the rat myeloma cell line Y3-Ag1.2.3 through receptor-mediated endocytosis. Importantly, the beta-galactosidase retains activity after internalization. Furthermore, we have unexpectedly discovered that anti-rat TfR IgG3-Av, but not a recombinant anti-rat TfR IgG3 or a nonspecific IgG3-Av, possesses proapoptotic activities against Y3-Ag1.2.3 and the rat T cell lymphoma cell line C58 (NT) D.1.G.OVAR.1. These activities were not observed in two rat cell lines of nonhematopoietic lineage (bladder carcinoma BC47 and gliosarcoma 9L). Anti-human TfR IgG3-Av also demonstrated proapoptotic activity against the human erythroleukemia cell line K562. Studies showed that anti-rat TfR IgG3-Av exists as a dimer, suggesting that cross-linking of the surface transferrin receptor may be responsible for the cytotoxic activity. These findings demonstrate that it is possible to transform an antibody specific for a growth factor receptor that does not exhibit inhibitory activity into a drug with significant intrinsic cytotoxic activity against selected cells by fusing it with avidin. The antitumor activity may be enhanced by delivering biotinylated therapeutics into cancer cells. Further development of this technology may lead to effective therapeutics for in vivo eradication of hematological malignancies, and ex vivo purging of cancer cells in autologous transplantation.
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PMID:An anti-transferrin receptor-avidin fusion protein exhibits both strong proapoptotic activity and the ability to deliver various molecules into cancer cells. 1214 72

A manometric sensor previously developed to measure urea was modified to measure glucose and lactose through enzymatic oxidation. Change in pressure in an enclosed cavity was correlated to the depletion of oxygen resulting from the enzymatic oxidation of glucose or lactose. The response of the sensor was linear and could be made adjustable over a large range by adjusting the amount of sample loaded into the fixed volume reactor. Because of the slow mutarotation of glucose, the oxidation of glucose was not allowed to proceed to completion. Therefore, the precision of the sensor (approximately 0.2 mM in a range from 0 to 5 mM) was limited by variations in the oxidation rate of glucose by glucose oxidase. Because the assay for lactose measured glucose subsequent to the hydrolysis of lactose by beta-galactosidase, the same degree of precision was observed in lactose. Milk lactose, typically at concentrations of about 150 mM, was estimated using the lactose assay after first diluting the samples. For many fluids such as milk, the use of manometric sensors for oxidizable substrates may be preferable to optical and electrochemical methods because they are robust and suffer a low degree of optical and chemical interferences. Glucose and lactose are representative of many important oxidizable substrates, which may be determined in this manner, many of which do not suffer from limitations caused by mutarotation. In theory, detection limits less than 1 microM may be achieved using these methods.
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PMID:Adaptation of a manometric biosensor to measure glucose and lactose. 1244 50

Of three beta-galactosidases from Aspergillus oryzae, Kluyveromyces lactis and Bacillus sp., used for the production of low-content galacto- oligosaccharides (GOS) from lactose, the latter produced the highest yield of trisaccharides and tetrasaccharides. GOS production was enhanced by mixing beta-galactosidase glucose oxidase. The low-content GOS syrups, produced either by beta-galactosidase alone or by the mixed enzyme system, were subjected to the fermentation by Kluyveromyces marxianus, whereby glucose, galactose, lactose and other disaccharides were depleted, resulting in up to 97% and 98% on a dry weight basis of high-content GOS with the yields of 31% and 32%, respectively.
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PMID:Production of high-content galacto-oligosaccharide by enzyme catalysis and fermentation with Kluyveromyces marxianus. 1678 43

We describe the fabrication of poly(ethylene glycol) diacrylate (PEG-DA) hydrogel microstructures with a high aspect ratio and the use of hydrogel microstructures containing the enzyme beta-galactosidase (beta-Gal) or glucose oxidase (GOx)/horseradish peroxidase (HRP) as biosensing components for the simultaneous detection of multiple analytes. The diameters of the hydrogel microstructures were almost the same at the top and at the bottom, indicating that no differential curing occurred through the thickness of the hydrogel microstructure. Using the hydrogel microstructures as microreactors, beta-Gal or GOx/HRP was trapped in the hydrogel array, and the time-dependent fluorescence intensities of the hydrogel array were investigated to determine the dynamic uptake of substrates into the PEG-DA hydrogel. The time required to reach steady-state fluorescence by glucose diffusing into the hydrogel and its enzymatic reactions with GOx and HRP was half the time required for resorufin beta-D-galactopyranoside (RGB) when used as the substrate for beta-Gal. Spatially addressed hydrogel microarrays containing different enzymes were micropatterned for the simultaneous detection of multiple analytes, and glucose and RGB solutions were incubated as substrates. These results indicate that there was no cross-talk between the beta-Gal-immobilizing hydrogel micropatches and the GOx/HRP-immobilizing micropatches.
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PMID:Photolithographic fabrication of poly(ethylene glycol) microstructures for hydrogel-based microreactors and spatially addressed microarrays. 1809 67

beta-Galactosidase is an hydrolase enzyme that catalyzes the hydrolysis of beta-galactosides into monosaccharides. Substrates of different beta-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. A novel aspect of the activity determination of beta-galactosidase was presented. A glucose oxidase biosensor based on Clark electrode was utilized in order to monitor beta-galactosidase. Immobilization of glucose oxidase was made by gelatin and glutaraldehyde as cross-linker. Several parameters such as glucose oxidase activity, gelatin amount, and glutaraldehyde percentage for cross-linking were optimized. The most important parameter, lactose concentration in working buffer was studied in detail. Optimum temperature, thermal stability, optimum pH, buffer system and its concentration effect on the biosensor system, repeatability, reproducibility, and storage and operational stabilities of the biosensor were identified. A linear detection range for beta-galactosidase was observed between 9.4 x 10(-5) and 3.2 x 10(-2)U/ml. Finally, beta-galactosidase activity in artificial intestinal juice was investigated by the biosensor and the results obtained were compared with a reference spectrophotometric method.
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PMID:Beta-galactosidase monitoring by a biosensor based on Clark electrode: its optimization, characterization and application. 1839 35

Sensors for the simultaneous determinations of sucrose and glucose, lactose and glucose, and starch and glucose were prepared by a combination of the enzyme system shown below and an oxygen electrode: The mechanism for separating the substrates with the proposed sensors is based on the time lag arising from reaction and diffusion. Invertase, beta-galactosidase, amyloglucosidase, mutarotase, and glucose oxidase were covalently immobilized on triacetyl cellulose membranes containing 1,8-diamino-4-aminomethyloctane. A glucose oxidase membrane, mutarotase membrane, three sheets of triacetyl cellulose membranes, and invertase, or beta-galactosidase or amyloglucosidase membrane were placed in that order on the tip of the oxygen electrode. Calibration curves for sucrose, lactose, and starch were linear up to 40 mM, 60-180 mM, and 10%, respectively. The simultaneous determination of sucrose and glucose, lactose and glucose, and starch and glucose was possible when the amount of glucose coexised was in the range of 2-16% sucrose, 2.8-8.3% lactose, or 0.1-1% starch. The relative errors were +/-4% for sucrose and +/-3% for lactose in 100 assays. The starch sensor was reused only five times. Each enzyme membrane was fairly stable for more than 10 days.
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PMID:Development of biosensors for the simultaneous determination of sucrose and glucose, lactose and glucose, and starch and glucose. 1860 Jul 3

Lactose and glucose concentrations were determined simultaneously by using a measuring-cell containing lactose and glucose electrodes made by mixing beta-galactosidase/glucose oxidase and glucose oxidase, respectively, with carbon paste. The glucose electrode responds to glucose alone, while the lactose electrode measures the sum of glucose and lactose. Lactose concentration was calculated by subtracting the glucose concentration from the reading of the lactose electrode. The present dual-working electrode system permitted the determination of lactose and glucose concentrations simultaneously from a single measurement over a linear range of 0.1-2.5 mM. Furthermore, it enabled the determination of lactose concentration in milk in the presence of glucose to be carried out more precisely and with a higher degree of sensitivity than the conventional calorimetric method.
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PMID:Simultaneous determination of lactose and glucose in milk using two working enzyme electrodes. 1896 8


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