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)

Factors affecting the beta-galactosidase production by Penicillium notatum 1 were studied using fermentation media of different chemical composition. The medium containing lactose, salts, peptone and yeast extract with initial pH 2.5 was selected as the best for enzyme production. Monobasic ammonium phosphate (0.9%) was found to be the best inorganic nitrogen source for lactase production. Various extraction media and metabolic inhibitors were examined for effective releasing of beta-galactosidase from the fungal cells. Using a simple method of mycelium extraction with 0.1 Triton X-100, it was possible to obtain about 4-fold higher amounts of enzyme in the cell free extracts, than those excreted into the post-culture liquid.
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PMID:Effect of medium components and metabolic inhibitors on beta-galactosidase production and secretion by Penicillium notatum 1. 881 42

The ontogeny and cellular specificity of expression of beta-galactosidase activity and olfactory marker protein (OMP) are compared in olfactory tissue of the H-OMP-lacZ-3 line of transgenic mice. In this line the expression of lacZ is driven by a 0.3 kb fragment of the rat OMP promoter. During fetal development, lacZ expression is detectable in olfactory receptor neurons (ORNs) shortly after the initial appearance of endogenous OMP. The beta-galactosidase marker was observed only in mature olfactory receptor neurons where it co-localized with endogenous OMP. It was absent from immature neurons that express the growth associated phosphoprotein B50/GAP43. Lesion of the peripheral olfactory pathway by intranasal irrigation with Triton X-100 eliminated expression of both OMP and lacZ in the olfactory neuroepithelium. Subsequent regeneration of the full complement of olfactory receptor neurons was associated with co-expression of both OMP and beta-galactosidase activity. Neither OMP nor beta-galactosidase activity was induced in any other cell type of the regenerating olfactory mucosa. Thus, as little as 0.3 kb of the OMP promoter has the ability to target lacZ expression to olfactory receptor neurons in a temporally and spatially defined manner. We discuss the potential utility of this transgenic line for future studies of the olfactory system.
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PMID:LacZ and OMP are co-expressed during ontogeny and regeneration in olfactory receptor neurons of OMP promoter-lacZ transgenic mice. 901 Jul 27

We have established the feasibility of using Neospora caninum as a heterologous system for the expression of genes from the closely-related parasite Toxoplasma gondii. Plasmid construct containing the lacZ gene from Escherichia coli driven by T. gondii promoters were electroporated into N. caninum parasites, and expression of beta-galactosidase (beta-Gal) activity was assayed enzymatically. In transient assays, expression of beta-Gal driven by the GRA1 promoter was approximately 10-fold higher than the expression obtained with the SAG1 promoter. Enzyme activity was not detected when N. caninum parasites were transfected with a promoterless lacZ construct. Transfection of N. caninum with complete genomic clones of SAG1 or GRA2 from T. gondii yielded parasites that transiently expressed the respective gene products, as detected by immunofluorescence and Western blot. Additionally, these transiently expressed T. gondii proteins appeared by immunofluorescence localization and Triton X-114 partitioning to be correctly targeted in both extracellular and intracellular N. caninum parasites. Heterologous gene expression should be useful for studying the function of specific gene products and may facilitate the identification of genes responsible for the phenotypic differences observed between these two closely-related apicomplexan parasites.
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PMID:Expression of Toxoplasma gondii genes in the closely-related apicomplexan parasite Neospora caninum. 917 65

Members of the Src family of protein tyrosine kinases are localized to subspecialized regions of the plasma membrane. Herein we show that the N-terminal SH4 region of the Src family member p59fyn (Fyn) is both necessary and sufficient for targeting of Fyn and heterologous proteins to the plasma membrane and detergent-insoluble subdomains. Attachment of the first 16 amino acids of Fyn to a normally cytosolic protein, beta-galactosidase, resulted in distinct plasma membrane localization of the chimeric protein. Mutation of the palmitoylation site (cysteine-3) within Fyn16-beta-galactosidase or wild-type Fyn abrogated plasma membrane localization, resulting in redistribution of the mutant proteins into intracellular membranes. Substitution of the SH4 motif within Fyn with heterologous sequences from other palmitoylated proteins (G alpha o and GAP43) revealed that the presence of palmitate is sufficient to direct plasma membrane localization independent of surrounding amino acid sequences and myristate. Palmitoylated Fyn chimeras were also enriched in the Triton X-100-resistant matrix, whereas nonpalmitoylated forms of these proteins were detected in the detergent-soluble fraction. The palmitate moiety on Fyn exhibited a half-life of 1.5-2 h. In contrast, the half-life of the polypeptide backbone was 8 h, indicating that palmitoylation is a reversible modification. These studies establish that the palmitoylated SH4 sequence of Fyn can be used to specifically target proteins to the plasma membrane in a reversible manner.
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PMID:Palmitoylation of p59fyn is reversible and sufficient for plasma membrane association. 920 23

GAP-43 is an abundant protein in axonal growth cones of developing and regenerating neurons. We found that GAP-43 was enriched in detergent-resistant membranes (DRMs) isolated by Triton X-100 extraction from PC12 pheochromocytoma cells and could be detected in detergent-insoluble plasma membrane remnants after extraction of cells in situ. GAP-43 is palmitoylated at Cys-3 and Cys-4. Mutation of either Cys residue prevented association with DRMs. A hybrid protein containing the first 20 amino acid residues of GAP-43 fused to beta-galactosidase was targeted to DRMs even more efficiently than GAP-43 itself. We conclude that tandem palmitoylated Cys residues can target GAP-43 to DRMs, defining a new signal for DRM targeting. We propose that tandem or closely spaced saturated fatty acyl chains partition into domains or "rafts" in the liquid-ordered phase, or a phase with similar properties, in cell membranes. These rafts are isolated as DRMs after detergent extraction. The brain-specific heterotrimeric G protein Go, which may be regulated by GAP-43 in vitro, was also enriched in DRMs from PC12 cells. Targeting of GAP-43 to rafts may function to facilitate signaling through Go. In addition, raft association may aid in sorting of GAP-43 into axonally directed vesicles in the trans-Golgi network.
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PMID:Association of GAP-43 with detergent-resistant membranes requires two palmitoylated cysteine residues. 977 77

The effective bioseparation process was developed by exploiting the cell response under heat, chemical, and combined stresses for selective recovery of cytoplasmic beta-galactosidase from Escherichia coli cells. At the observed optimal condition for heat stress (45 degrees C, 30 min) and that for chemical stress (20 mM Triton X-100, 5 mM EDTA, 30 min), E. coli cells were exposed to these stresses either simultaneously or sequentially. The operational sequence highly affected the yield and selectivity of the target recovery. Exposing the cells to the sequential stress (heating at 45 degrees C for more than 30 min after Triton X-100/EDTA treatment for 30 min) was found to be most effective for selective recovery of target beta-galactosidase among possible sequences.
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PMID:Utilization of cell response under heat, chemical, and combined stresses for selective recovery of cytoplasmic beta-galactosidase from Escherichia coli cells. 984 55

The olfactory epithelium (OE) is unusual in its ability to regenerate and reinnervate its target, the olfactory bulb (OB), after deafferentation. To address the question of whether olfactory receptor neuron (ORN) axons preserve their topographic organization when they reestablish synaptic contact with the OB, the authors examined the pattern of ORN axon reinnervation into the bulb of adult H-OMP-lacZ-6 transgenic mice during and after recovery from chemical deafferentation. In the H-OMP-lacZ-6 mouse strain, lacZ expression is limited to a subset of ORNs that are distributed bilaterally in the OE and project primarily to a few glomeruli in the ventromedial region of the OB. The OE was lesioned by intranasal irrigation with Triton X-100, and the distribution of 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal)-stained cells was examined in the OE along with beta-galactosidase-immunoreactive (beta-gal-ir) axonal processes in the OB after short (1 week), intermediate (3 week), and long (6-7 weeks) recovery times. One week after the lesion, immunostaining for beta-gal and olfactory marker protein was virtually eliminated in the bulb. After 3 weeks of recovery, beta-gal-containing axons appeared to target many of the same locations innervated in bulbs of unlesioned mice. The region that received the highest density of axonal innervation in controls, however, contained only a few processes at that time. After 6-7 week recovery periods, the pattern of X-gal staining in the OE and beta-gal-ir axons in the OB closely resembled that of unlesioned mice. These results demonstrate that the topographic distribution of ORNs in the OE and the pattern of axon innervation in the OB can be reconstituted after chemical deafferentation.
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PMID:Pattern of olfactory bulb innervation returns after recovery from reversible peripheral deafferentation. 1081 92

The effect of bio-surfaces of contrasting curvature, on the kinetic parameters of ortho-nitrophenyl-beta-D-galactopiranoside hydrolysis catalyzed by E. coli beta-galactosidase, was investigated. The self-aggregating state and structure of the amphiphiles (Phosphatidylcholine, Lubrol-PX, Triton X-100, DocNa, SDS and CTAB) were inferred from their c.m.c. values and light-scattering measurements. Low curvature phosphatidylcholine or mixed phosphatidylcholine-detergent vesicles increased V(max) without affecting K(M). High curvature micellar structures containing ionic detergents modulated negatively the enzyme activity (decreased or abolished V(max) and increased K(M)). Neither micelles containing non-ionic detergents nor the amphiphiles in a monomeric form, affected enzyme activity. CTAB at a concentration below its c.m.c but incorporated into a bilayer, became an activator (K(M) decreased respect to the control). Non-enzymatic interfacial hydrolysis of the substrate was discarded. Enzyme-membrane interaction and membrane elasticity, were evaluated using monomolecular layers at the air-water interface. Beyond particular molecular structures, topology affected the direction of the modulatory effects exerted by these amphiphiles on beta-galactosidase activity.
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PMID:Membrane topology modulates beta-galactosidase activity against soluble substrates. 1240 42

The midgut of the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae) larvae has four beta-glycosidases. The properties of two of these enzymes (betaGly1 and betaGly2) have been described elsewhere. In this paper, the characterization of the other two glycosidases (betaGly3 and betaGly4) is described. BetaGly3 has one active site, hydrolyzes disaccharides, cellodextrins, synthetic substrates and beta-glucosides produced by plants. The enzyme is inhibited by amygdalin, cellotriose, cellotetraose and cellopentaose in high concentrations, probably due to transglycosylation. betaGly3 hydrolyzes beta 1,4-glycosidic linkages with a catalytic rate independent of the substrate polymerization degree (k(int)) of 11.9 s(-1). Its active site is formed by four subsites, where subsites +1 and -1 bind glucose residues with higher affinity than subsite +2. The main role of betaGly3 seems to be disaccharide hydrolysis. BetaGly4 is a beta-galactosidase, since it has highest activity against beta-galactosides. It can also hydrolyze fucosides, but not glucosides, and has Triton X-100 as a non-essential activator (K(a)=15 microM, pH 4.5). betaGly4 has two active sites that can hydrolyze p-nitrophenyl beta-galactoside (NPbetaGal). The one hydrolyzing NPbetaGal with more efficiency is also active against methylumbellipheryl beta-D-galactoside and lactose. The other active site hydrolyzes NPbetaFucoside and binds NPbetaGal weakly. BetaGly4 hydrolyzes hydrophobic substrates with high catalytical efficiency and is able to bind octyl-beta-thiogalactoside in its active site with high affinity. The betaGly4 physiological role is supposed to be the hydrolysis of galactolipids that are found in membranes from vegetal tissues. As the enzyme has a hydrophobic site where Triton X-100 can bind, it might be activated by membrane lipids, thus becoming fully active only at the surface of cell membranes.
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PMID:Characterization of a beta-glycosidase highly active on disaccharides and of a beta-galactosidase from Tenebrio molitor midgut lumen. 1253 83

Galactosyltransferase (GalT) activity that results in the transfer of galactose (Gal) from UDP-Gal to exogenous (1-->4)-beta-galactooligosaccharides labeled with 2-aminobenzamide (2AB) at their reducing ends was identified in a particulate preparation obtained from 2-day-old mung bean (Vigna radiata L. Wilezek) hypocotyls. The enzymes responsible were shown, by high-performance anion-exchange chromatography and normal-phase liquid chromatography-electrospray ionization mass spectrometry, to transfer up to eight Gals to the non-reducing end of 2AB-labeled galactooligosaccharide. Using 1H nuclear magnetic resonance spectroscopy, and beta-galactosidase and endo-beta-(1-->4)-galactanase treatments of the enzymatically formed 2AB-labeled galactooligosaccharides, the newly incorporated Gal residues were shown to be beta-(1-->4) linked. Time-course studies indicated that at least two different types of GalT isoform are involved in the elongation of the acceptor substrates. 2AB-labeled galactoheptaose was the most effective acceptor substrate analyzed, although galactooligosaccharides with a degree of polymerization between 4 and 6 were also acceptor substrates. 2AB-labeled penta- and heptasaccharides (RG5 and RG7) generated from rhamnogalacturonan I (RG-I) were not acceptor substrates, suggesting that the GalTs were not capable of adding Gal residues directly to the RG-I backbone. Maximum GalT activity was obtained at pH 6.5 and 20 degrees C in the presence of 25 mM Mn2+ and 0.75% (w/v) Triton X-100. The enzyme had an apparent Km of 20 microM for 2AB-labeled galactoheptaose and 32 microM for UDP-Gal. The characteristics of the enzyme in mung bean microsomal membranes and the usefulness of fluorogenic 2AB-labeled galactooligosaccharides for the assay of GalT are discussed.
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PMID:Identification of elongating beta-1,4-galactosyltransferase activity in mung bean (Vigna radiata) hypocotyls using 2-aminobenzaminated 1,4-linked beta- D-galactooligosaccharides as acceptor substrates. 1498 44


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