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)

We developed a sensitive and specific heterogeneous enzyme immunoassay for measuring angiotensin I (AI) or renin (EC 3.4.99.19) activities. Linking AI under carefully controlled conditions by means of N-succinimidyl-3-(2-pyridyldithio)propionate to highly purified beta-D-galactosidase (EC 3.2.1.23) produced a well-defined conjugate in high yield. The procedure is simple and consists of three steps: (a) incubate 0.5 mL of plasma with 100 microL of inhibitor solution for 1 h to generate renin activity; (b) incubate this with labeled AI for 1 h at 37 degrees C; and (c) do a double-antibody precipitation. Bound beta-D-galactosidase activity is determined, with O-nitrophenyl-beta-D-galactoside as substrate, by measuring the liberated O-nitrophenol at 410-420 nm. The analytical range of the assay extends from 62.5 to 4000 ng/L, and renin activities so measured in plasma correlate well with those measured by an established radioimmunoassay (n = 35, r = 0.97, intercept -0.6, and slope 1.44).
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PMID:Enzyme immunoassay of angiotensin I and renin. 311 31

A brother and sister with clinical and radiological features of Morquio disease, but with atypical mental regression, are described. Leucocyte and fibroblast beta-galactosidase activity was deficient in the siblings, while N-acetylgalactosamine 6-sulphate sulphatase and neuraminidase were normal. Study of the residual fibroblast beta-galactosidase activity towards 4-methylumbelliferyl and p-nitrophenyl beta-D-galactosides indicated that the mutation resembles that in typical Morquio B disease (increased Km and similar pH maximum) rather than that in GM1-gangliosidosis. The patients have therefore been classified as having Morquio B disease with atypical mental regression rather than GM1-gangliosidosis variants with particularly severe bony abnormalities. The mutation was, however, distinct from that in Morquio B disease since residual activity towards the alternative artificial substrate 4-methylumbelliferyl-beta-D-fucoside was increased. The patients represent further examples of the heterogeneity that can result from mutation at the beta-galactosidase locus.
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PMID:Progressive mental regression in siblings with Morquio disease type B (mucopolysaccharidosis IV B). 312 Dec 19

We established a new method for detecting enteropathogenic Escherichia coli adhering to HEp-2 cells. An essential part of the method is an assay of beta-galactosidase activity of adhered bacterial cells. It consisted of the following steps: (1) culture of bacterial cells in a medium containing isopropyl-thio-beta-D-galactoside, an inducer of beta-galactosidase; (2) incubation of a bacterial culture with monolayered HEp-2 cells in a 96-well culture plate; (3) washing wells to remove bacterial cells which did not adhere to HEp-2 cells, and (4) enzymic reaction for beta-galactosidase activities. However, a calibration curve for the enzyme activity, obtained from each bacterial sample, showed that 10(5) bacteria per well permitted an accurate estimation. The enzyme activity of adhered bacteria to the monolayered cells showed that 10(7) bacteria were appropriate for the adherence assay. The number of adhered bacteria thus obtained was in good agreement with a viable cell count. The result indicates that the new method is more reliable than a widely used method, counting the number of bacteria under a microscope. The present method also makes it easy to detect adherent strains of E. coli in large numbers of specimens.
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PMID:Enzymic detection of adhesion of enteropathogenic Escherichia coli to HEp-2 cells. 312 86

beta-Galactosidases were purified to homogeneity from livers of a normal control and a patient with the adult form of GM1 gangliosidosis. The purification was achieved by chromatography on DEAE-Sepharose fast flow, Con A-Sepharose, p-aminophenyl-1-thio-beta-D-galactopyranoside-Sepharose, and QAE-Mono Q. The normal and mutant enzymes were purified about 5000-fold with a yield of 10% and 1800-fold with a yield of 34%, respectively, and could hydrolyze 4-methylumbelliferyl-beta-D-galactoside, GM1 ganglioside, and asialofetuin. The purified normal enzyme was eluted from a TSK gel G-4000SW column as three symmetrical peaks of protein which were coincident with the three peaks of enzyme activity. The enzyme in these three peaks had apparent molecular weights of 800,000 (polymer), 140,000 (dimer), and 65,000 (monomer), whereas the mutant enzyme was eluted as two symmetrical peaks of protein and enzyme activity. The apparent molecular weight of a major monomeric form of the enzyme (beta-galactosidase A) was 60,000, and no dimeric form of the enzyme existed. Normal and mutant purified enzyme preparations migrated as a single major protein band with apparent molecular weights of 65,000 or 60,000, respectively, by SDS-polyacrylamide gel electrophoresis after treatment with mercaptoethanol. On isoelectric focussing, the mutant enzyme migrated more anodally than the normal enzyme. The mutant enzyme also had altered enzyme properties, such as pH optimum, Km values, substrate specificity and heat-stability. These data on the characteristics of the purified enzyme preparations provide the first direct evidence that patients with the adult form of GM1 gangliosidosis have a structurally altered beta-galactosidase.
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PMID:Purification and characterization of human liver beta-galactosidase from a patient with the adult form of GM1 gangliosidosis and a normal control. 312 90

A non-radioisotopic and sensitive method for quantification of specific DNA immobilized in microtiter wells has been developed. This method is based upon the immobilization of DNA in microtiter wells and hybridization with biotinylated DNA probe which is followed by complexing with avidin-beta-galactosidase. By measuring fluorescence emitted from the hydrolyzed product by beta-galactosidase of 4-methylumbelliferyl-beta-D-galactoside, it has become possible to quantify a few picograms of specific DNA in DNA samples immobilized in plastic microtiter wells.
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PMID:Quantification of picogram levels of specific DNA immobilized in microtiter wells. 315 98

A double antibody sandwich immunoassay (EIA) was developed for the detection of Salmonella. The assay utilizes a beta-galactosidase-murine myeloma monoclonal antibody (M467) conjugate prepared with the heterobifunctional coupling reagent, N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) and uses 4-methyl umbelliferyl beta-D-galactoside as a fluorogenic substrate for the enzyme. The EIA is sensitive and rapid, and compared favorably with the conventional cultural technique in the analysis of 60 feed samples naturally contaminated with Salmonella. Proteins or natural contaminants from the sample did not interfere in the assay.
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PMID:A fluorescent enzyme immunoassay for Salmonella detection. 328 71

We have developed a fluorometric enzyme-linked immunosorbent assay for measuring IgE antibody to Dermatophagoides farinae. Polystyrene microplates were coated with proteins extracted from the mites. The IgE antibody which attached to the solid-phase antigen was detected by anti-IgE antibody conjugated with beta-galactosidase. Four-methylumbelliferyl-beta-D-galactoside was used as the enzyme substrate and the fluorescence intensity of the reaction product was measured. The antibody levels determined by this method well correlated with those determined by the radioallergosorbent test (RAST). This method is simpler and less expensive to carry out than the RAST when dealing with a large number of serum specimens for seroepidemiological studies of asthma and nasal allergy.
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PMID:Fluorometric enzyme-linked immunosorbent assay for the measurement of IgE antibody to mite Dermatophagoides farinae. 332 83

Relationships between cholinergic neurons and adrenergic fibers in the intermediate region of the rat thoracic spinal cord were examined using a new immunohistochemical double-staining method for light and electron microscopic observations. Cholinergic neurons were labeled by a monoclonal antibody to choline acetyltransferase and stained bluish green by 5-bromo-4-chloro-3-indolyl-beta-D-galactoside reaction products using beta-galactosidase as a marker. On the same sections, adrenergic fibers were labeled by a polyclonal antiserum to phenyl-ethanolamine-N-methyltransferase and stained brown by diaminobenzidine reaction products using peroxidase as a marker. After embedding in Epon, the sections were examined in the light and electron microscopes. In the light microscope, choline acetyltransferase-like immunoreactive cells were seen in the four discrete areas of the intermediate region: the principal intermediolateral nucleus, the central autonomic nucleus, the intercalated nucleus and the funicular intermediolateral nucleus. These cell groups seemed to be connected to each other by their processes, and they showed a "ladder-like appearance" as a whole. Phenylethanolamine-N-methyltransferase-like immunoreactive fibers were present only along this "ladder-like structure" and were the most rich in the principal intermediolateral nucleus. In the electron microscope, some of the choline acetyltransferase-like immunoreactive neurons, which were identified by light micrographs, were found to receive synaptic inputs from phenylethanolamine-N-methyltransferase-like immunoreactive boutons in the principal intermediolateral nucleus. These findings suggest that the adrenergic axons in the principal intermediolateral nucleus directly affect the activity of the cholinergic preganglionic sympathetic neurons.
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PMID:Interaction between adrenergic fibers and intermediate cholinergic neurons in the rat spinal cord: a new double-immunostaining method for correlated light and electron microscopic observations. 339 73

In steady state E. coli cells growing at their maximal rate in broth, maximum induction of beta-galactosidase occurs at 0.10 mM isopropyl-thio-beta-D-galactoside (IPTG). Although induction of lac is near zero in steady state cells that are growing in 0.01 mM IPTG, induction at mildly subdued levels persists down to at least 0.001 mM in post-steady state cultures. Meanwhile, thiogalactoside transacetylase remains uninduced over the full range in which the cells are in steady state.
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PMID:Effect of iso-propyl-thio-beta-D-galactoside concentration on the level of lac-operon induction in steady state Escherichia coli. 392 43

The general methodology used for the determination of lactose in milk is considered, namely, polarimetry, gravimetry, infrared, colorimetry, gas-liquid chromatography, and high pressure liquid chromatography. The criteria for selecting an ideal analytical method followed by the relevance of most of these criteria in enzymatic methodology are discussed. The principle of the Boehringer-Mannheim method is presented, i.e., lactose is hydrolyzed to glucose and beta-galactose in the presence of beta-galactosidase and water. beta-Galactose is then oxidized by nicotinamide-adenine dinucleotide to galactonic acid in the presence of beta-galactose dehydrogenase. The amount of reduced nicotinamide-adenine dinucleotide formed is stoichiometric with the amount of lactose and is measured at 340 nm in a spectrophotometer possessing a slit width of less than or equal to 10 nm. The results of a recent Association of Official Analytical Chemists collaborative study of the B-M method are presented. From the overall mean of results on all samples, determinations by the enzymatic method averaged .49% lower than by the Association of Official Analytical Chemists gravimetric method. Standard deviations were similar for three sets of blind duplicates, which ranged between 3.67 and 4.55% lactose. F-Values revealed that variations between means obtained by laboratories differed significantly as compared with variations within laboratory means. The method has received Official First Action recognition by Association of Official Analytical Chemists.
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PMID:Determination of lactose by an enzymatic method. 406 42


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