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)

Methods for isolation and purification of beta-galactosidase from Bacillus subtilis, st. IBP-101 are described. The bacterial cells were disrupted by different procedures such as freezing and thawing with subsequent autolysis at 37 degrees C, disrupting in a French press DKM-3 or in ultrasonic disintegrators UZDN-1 (USSR) and Soniprep-150. It is shown that the specific activity and yield of the enzyme depends to a great extent on the disrupting procedure used. The best results were obtained in case of sonication. The preparation was purified by precipitation with ammonium sulphate (25-75% saturated) and chromatography on DEAE-cellulose and DEAE-Sephadex. The purified enzyme had a specific activity of 3155 units per mg protein. The molecular weight of the homogeneous according to gel polyacrylamide electrophoresis preparation was 215,000, as estimated by gel filtration, and 105,000, as estimated by SDS gel electrophoresis. The enzyme retains the activity in the presence of Na+, Mn2+ or Mg2+ ions or the thiolic reagents, dithiothreitol or 2-mercaptoethanol. The pH optimum of the enzyme activity is 6.3 and it is stable in water solutions at pH from 6 to 9 and can be lyophilized. The given preparation of beta-galactosidase has a high affinity for synthetic substrates such as o- and p-nitrophenyl-beta-D-galactopyranosides and 4-methylumbelliferyl-beta-D-galactopyranoside.
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PMID:[Isolation of a highly active preparation of beta-D-galactosidase]. 311 62

Three Portuguese water dog siblings, all females aged 5 to 7 months, were killed following a brief period of neurologic disease. Tissues were processed for light and electron microscopy and for biochemical analyses. All pups had membranous cytoplasmic inclusions in neurons throughout the brain and spinal cord. Cytoplasmic vacuoles were present in cells of many organs outside the nervous system. GM1 ganglioside in brain was markedly elevated in all three dogs, and beta-galactosidase activity was less than 10% of control values. These findings are similar to those in GM1 gangliosidosis of man and animals although the number of organs and tissues containing vacuolated cells is greater.
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PMID:GM1 gangliosidosis in Portuguese water dogs: pathologic and biochemical findings. 313 86

The cytochrome d terminal oxidase complex is a component of the aerobic respiratory chain of Escherichia coli. This enzyme catalyzes the oxidation of ubiquinol-8 within the cytoplasmic membrane and the reduction of molecular oxygen to water along with the concomitant generation of a proton-motive force across the membrane. Previous studies have established that the oxidase is composed of one copy of each of two subunits (I and II), and contains four heme prosthetic groups. The hydropathy profiles of the amino acid sequences suggest that each subunit has multiple transmembrane-spanning helical segments. The goal of the current work is to obtain experimental information about which portions of the two polypeptide chains are facing the cytoplasm. This is part of an effort to determine the topological folding of the two subunits across the membrane. A number of random gene fusions were generated in vitro which encode hybrid proteins in which the amino-terminal portion is provided by one of the two subunits of the oxidase, and the carboxyl-terminal portion is beta-galactosidase. Studies from other systems have indicated that the only hybrid proteins which will manifest high beta-galactosidase specific activity and be membrane-bound will be those where the fusion junction is in a region of the cytochrome polypeptides facing the cytoplasm. Fusions were obtained in eight positions within subunit I and 11 positions within subunit II. These identified four cytoplasmic-facing regions within subunit II, consistent with its hydropathy profile showing eight transmembrane helices. The data with subunit I are less conclusive.
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PMID:Beta-galactosidase gene fusions as probes for the cytoplasmic regions of subunits I and II of the membrane-bound cytochrome d terminal oxidase from Escherichia coli. 313 32

Each epididymis of control and swainsonine-fed rats (5 micrograms/ml drinking water) was divided into 5 segments, and tissue, spermatozoa and sperm-free supernatants were prepared from each segment. When levels of 3 lysosomal glycosidases and total protein were determined, the proximal cauda contained the greatest concentration of glycosidase. The specific-activity profile for beta-glucuronidase and beta-galactosidase was similar in swainsonine-fed and control rats. However, the concentration of alpha-D-mannosidase in tissue of all segments was significantly greater in swainsonine-fed rats than in age-matched controls. Enzyme activity for alpha-D-mannosidase after swainsonine treatment was significantly greater in spermatozoa from the caput, than in spermatozoa from the corpus and the cauda epididymidis. Since the alpha-D-mannosidase activity was optimal at pH 4.5 and studies with highly specific antibody to lysosomal alpha-D-mannosidase immunoprecipitated all of the alpha-D-mannosidase present in detergent extracts of epididymal tissue, spermatozoa, and sperm-free supernatant, the enzyme studied is of lysosomal origin.
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PMID:Effect of swainsonine on rat epididymal glycosidases. 314 32

The enzyme beta-galactosidase has been immobilized within thermally reversible hydrogel beads that exhibit LCST (lower critical solution temperature) behavior. The hydrogel beads containing the immobilized enzymes swell and expand below the LCST and deswell and shrink above the LCST. This behavior is reversible. The enzyme was physically entrapped in a crosslinked hydrogel of a copolymer of N-isopropylacrylamide (NIPAAm) and acrylamide (AAm), and formed as beads in an inverse suspension polymerization. The beads were placed in a packed bed column reactor which was operated in a continuous, single pass mode, either isothermally at 30 or 35 degrees C, or with temperature cycling between 30 and 35 degrees C. The thermal cycling significantly enhanced overall reactor enzyme activity relative to isothermal operation at either the higher or lower temperature. It is postulated that mass transfer rates within the hydrogel beads are greatly enhanced by the movement of water in and out of the beads during the expansion or collapse of the polymer chain network as temperature is cycled.
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PMID:Effect of temperature cycling on the activity and productivity of immobilized beta-galactosidase in a thermally reversible hydrogel bead reactor. 314 42

Phycoerythrin, ferritin, urease, beta-galactosidase and thyroglobulin, with molecular masses in excess of 200 kDa, adsorb and consequently fail to migrate to, and focus at, their pI positions in electrofocusing in immobilized pH gradients at a total Immobiline concentration of 20 mM while they do focus normally in pH gradients formed by carrier ampholytes. The addition of carrier ampholytes (pH range 3.5-9.5) at concentrations of 0.1 to 5% to the Immobiline-containing gels reduces adsorption (desorbs) some but not all of the 5 proteins at specific Immobiline concentrations. The adsorption is not due to water redistribution and consequent reduction in gel porosity; nor is it due to conductivity minima across the pH gradient. The hypothesis that the presence of oligomeric Immobiline contributed to the protein adsorption is the subject of the accompanying report.
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PMID:The adsorption of large proteins in electrofocusing on immobilized pH gradients: I. Protein specificity and dependence on Immobiline and carrier ampholyte concentrations. 324 43

N-methyl-N-nitrosoguanidine (MNNG) decomposition kinetics in H2O was studied under in vitro conditions by spectrometry in different buffers and at different pH. Parallely the change of mutagenic activity of decomposing mixture was studied by SOS chromotest (in which the change of beta-galactosidase was observed). The MNNG decomposition was confirmed to be the reaction of the pseudofirst order. MNNG mutagenic activity decreases parallely with MNNG decomposition. From the observed facts it has been concluded that the MNNG decomposition proceeding outside the biological target gradually leads to the inactive stable decomposition products.
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PMID:Change of mutagenic activity of N-methyl-N-nitrosoguanidine during its decomposition studied by SOS chromotest. 353 95

A reverse micellar system containing Tween 85 and water in isopropylpalmitate was developed which permitted the solubilization of bacteria in the form of homogenous organic solutions. The presence of the bacteria in solution was demonstrated by light microscopy. Immediately after solubilization, isolated bacterial cells were observed, which by aging tend to form larger aggregates. Cells of Escherichia coli remained viable in this system for at least one day and retained beta-galactosidase activity for an even longer period as indicated by the hydrolysis of x-gal. Cells of an alkane-degrading strain of Acinetobacter calcoaceticus remained viable in the system for several days.
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PMID:Solubilization of bacterial cells in organic solvents via reverse micelles. 392 Oct 20

An enzyme immunoassay (EIA) was developed to screen for residues of sulfamethazine (SMT) and its metabolites in swine blood. Swine blood was treated with perchloric acid and centrifuged. The supernatant solution was neutralized with K2HPO4, centrifuged, and applied to a reverse phase C8 cartridge. The analytes were eluted with methanol-water (2 + 3), and the eluate was diluted and assayed. Average recoveries, using 14C-labeled compounds, were 73, 72, 61, and 62% for SMT, N4-glucosylSMT, N4-acetylSMT, and N4-desaminoSMT, respectively. Tubes coated with antibody were incubated with the eluate and an SMT-beta-galactosidase conjugate. Bound enzyme was detected with fluorogenic substrate. When blood was fortified with 0.1 ppm SMT or a molar equivalent of metabolite, the average relative response of the EIA was 100%, control blood; 61%, SMT; 66%, glucosylSMT; 60%, acetylSMT; and 77% desaminoSMT.
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PMID:Enzyme immunoassay for screening sulfamethazine residues in swine blood. 392 22

The effects of a chronic load of nonabsorbable sugars on intracolonic bacterial metabolism of carbohydrates and on H2 breath excretion are disputed. However, most of the discussion relies on indirect evidence or on results of in vitro studies. Thus, we attempted to assess directly and in vivo the effects on intracolonic metabolism of lactulose of a chronic oral load of this nonabsorbable disaccharide. 20 g of lactulose was given orally twice daily during 8 d to eight normal volunteers. In all, breath H2 concentration was measured on days 1 and 8 after ingestion of the morning lactulose dose. In four subjects, stools were collected during 2 d at the beginning and at the end of the lactulose maintenance period to measure fecal pH and daily outputs of carbohydrates and beta-galactosidase. The four other subjects were intubated on days 1 and 8 to measure the pH and the concentrations of carbohydrates, lactic acid, and volatile fatty acids (VFA) in the distal ileum and cecal contents. Moreover, 14C-lactulose was added to cold lactulose and 14CO2 breath outputs determined. Pulmonary H2 excretion fell from day 1 to day 8 (P less than 0.05), whereas 14CO2 excretion increased (P less than 0.01). Fecal water pH, lactic acid, and VFA concentrations did not vary between the two stool collection periods. 24-h fecal weight, fecal water, and carbohydrate outputs showed a trend to decrease between days 1 and 2 and days 7-8, whereas beta-galactosidase activity rose markedly (P less than 0.01). No significant variations were observed for all parameters measured in ileal fluid. In the cecum, areas under the concentration curves decreased from day 1 to day 8 for lactulose, galactose, and fructose (P less than 0.01), while an increase was found for lactic acid (P less than 0.001), acetic acid (P less than 0.0001), and total VFA (P less than 0.001). Cecal fluid pH dropped faster (P less than 0.05) and to a lower level (P less than 0.05) on day 8 than on day 1. These data clearly show that a chronic load of a nonabsorbable sugar induces changes in colonic bacterial metabolic pathways resulting in a better efficiency of the flora to digest the carbohydrate.
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PMID:Influence of chronic lactulose ingestion on the colonic metabolism of lactulose in man (an in vivo study). 397 20


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