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)

The beige mouse is an animal model for the human Chediak-Higashi syndrome, a disease characterized by giant lysosomes in most cell types. In mice, treatment with androgenic hormones causes a 20-50-fold elevation in at least one kidney lysosomal enzyme, beta-glucuronidase. Beige mice treated with androgen had significantly higher kidney beta-glucuronidase, beta-galactosidase, and N-acetyl-beta-D-glucosaminidase (hexosaminidase) levels than normal mice. Other androgen-inducible enzymes and enzyme markers for the cytosol, mitochondria, and peroxisomes were not increased in kidney of beige mice. No significant lysosomal enzyme elevation was observed in five other organs of beige mice with or without androgen treatment, nor in kidneys of beige females not treated with androgen. Histochemical staining for glucuronidase together with subcellular fractionation showed that the higher glucuronidase content of beige mouse kidney is caused by a striking accumulation of giant glucuronidase-containing lysosomes in tubule cells near the corticomedullary boundary. In normal mice lysosomal enzymes are coordinately released into the lumen of the kidney tubules and appreciable amounts of lysosomal enzymes are present in the urine. Levels of urinary lysosomal enzymes are much lower in beige mice than in normal mice. It appears that lysosomes may accumulate in beige mice because of defective exocytosis resulting either from decreased intracellular motility of lysosomes or from their improper fusion with the plasma membrane. A similar defect could account for characteristics of the Chediak-Higashi syndrome.
J Cell Biol 1975 Dec
PMID:Defective lysosomal enzyme secretion in kidneys of Chediak-Higashi (beige) mice. 0 Apr 8

N-Bromoacetyl-beta-D-galactosylamine is an irreversible inhibitor of the 'acid' and the 'neutral' beta-galactosidases (beta-D-galactoside galactohydrolase, EC 3.2.1.23) of human liver. The inactivation of acid beta-galactosidase appears to involve a group with a pKa = 4.5. The inhibition of neutral beta-galactosidase only occurs above pH 8.0. Both enzymes are protected against inhibition by the presence of substrates, suggesting that the inhibitor reacts with the active site of the enzymes. Other lysosomal hydrolases are not inhibited by N-bromoacetyl-beta-D-galactosylamine, with the exception of 'neutral' beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21). The pH dependence of neutral beta-glucosidase inactivation is essentially identical to that of the neutral beta-galactosidase. Inhibition of beta-glucosidase by this galactose derivative suggests that the same enzyme may bind glucosides and galactosides. Furthermore, both neutral beta-galactosidase and beta-glucosidase are inactivated at 52 degrees C with a half-life of 7.5 min. The presence of a single enzyme with both beta-glucosidase and beta-galactosidase activities is also supported by mixed-substrate experiments.
Biochim Biophys Acta 1975 Dec 18
PMID:Inhibition of human liver beta-galactosidases and beta-glucosidase by n-bromoacetyl-beta-D-galactosylamine. 0 Oct 95

1. The p-nitrophenyl beta-D-galactosidase asctivity in rat liver homogenates of lysosome-rich fractions was shown to be markedly affected by the ionic composition of the medium. A stimulation of the reaction rate at pH 5 was produced by most of the salts tested, which contained anions such as acetate, SO4(2-) and Cl-, and cations such as Na+, K= and Mg2+. The most pronounced effect was observed with MgCl2. Only potassium glutamate was inhibitory. 2. Five peaks of beta-galactosidase activity obtained by DEAE-cellulose chromatography were equally sensitive to changes in the ionic composition of the medium. In the presence of added NaC1, the whole rate-pH curve was displaced towards higher pH values, the optimum being shifted from 2.0-2.5 to 3.5. The stimulation at pH 5.0 appeared to be mainly due to changes in Vmax., whereas the apparent Km was slightly modified. 3. Unlike the total, the free beta-galactosidase activity remained unchanged or even declined when KC1 was added to the reaction medium.
Biochem J 1975 Dec
PMID:Stimulation of rat liver beta-galactosidase activity by ions. 0 74

Colorimetric methods using 4-nitrophenyl-glycoside substrates for the assay of beta-galactosidase and N-acetyl-beta-glucosaminidase in human urine are described. Interfering substances were removed by gel-filtration of urine. An unidentified low-molecular-weight inhibitor of N-acetyl-beta-glucosaminidase was found. Increased sensitivity of the methods was achieved by high sample volumes, small volumes of buffer to terminate the enzyme reaction and optimal substrate concentration and buffer pH. Incubation periods were shortened to 15 min. Both methods were designed as single-tube tests in which buffer-substrate solutions are prepared in bulk and aliquots are stored in individual containers at -25 degrees C. Under these conditions reagents were stable for at least six months. Precision of both methods was satisfactory. Estimates of normal limits are reported.
Clin Chim Acta 1976 Dec
PMID:Rapid colorimetric assay of beta-galactosidase and N-acetyl-beta-glucosaminidase in human urine. 1 13

beta-Galactosidase [EC 3.2.1.23] was isolated from a partially purified preparation obtained from cultured cells of a special strain of Aspergillus oryzae, RT 102 (FERM-P1680). The enzyme preparation gave a single protein band on polyacrylamide gel electrophoresis and was free from alpha-galactosidase, alpha- and beta-mannosidase, alpha- and beta-N-acetylhexosaminidase, and protease activities. The beta-galactosidase was capable of acting on aryl beta-galactosides, lactose, and lactosides. It also hydrolyzed beta-galactosyl linkages in urinary glycoasparagines and asialo alpha1-acid glycoprotein. The enzyme was rather stable in aqueous solution, retaining full activity at 4 degrees for at least several months. At pH 4.5, the optimum pH for the enzyme activity, and 37 degrees, full activity was maintained for several days.
J Biochem 1976 Dec
PMID:Characterization of beta-galactosidase from a special strain of Aspergillus oryzae. 1 18

Mutants of Escherichia coli have been isolated that are able to grow on lactose at pH 7.0 but not at pH 8.1. One of these mutants was analyzed and shown to map in the Z region of the lactose operon. beta-Galactosidase (beta-D-galactoside galactohydrolase; EC 3.2.1.23) activity in toluenized mutant cells at pH 8.0 was one-tenth that at pH 7.0. Enzyme purified to near homogeneity from the pH-conditional mutant similarly exhibited pH-conditional activity under conditions where wild-type enzyme was unaffected over a pH range of 6.0-8.0. The pH-conditional beta-galactosidase was used in vivo as a probe for intracellular pH. We show that an internal pH of approximately 7.8-8.0 is maintained through an external pH range of 5.9-7.8. The phenotype of pH-conditional mutants was defined on medium with lactose as the sole carbon source. Under such conditions the gene product itself, beta-galactosidase, is required to maintain intracellular pH, since such maintenance is clearly energy-dependent. Therefore, we were able to recover a pH-conditional mutant in a cytoplasmic gene product. We predict that with any phenotype independent of energy production, however, pH-sensitive mutants will be recovered only in surface elements.
Proc Natl Acad Sci U S A 1977 Dec
PMID:A pH-conditional mutant of Escherichia coli. 2 35

Antisera against tetrahydronaphthalenols, which are conformationally rigid derivatives of adrenergic catecholamine, were produced in rabbits immunized with trans-5-amino-6-hydroxy-2-isopropylamino-1,2,3,4-tetrahydronaphthalene-1 -ol (I) conjugated to succinylated bovine serum albumin at the C5 position on the tetralin ring. Antisera were screened by immunodiffusion and further characterized by passive hemagglutination assay using erythrocytes sensitized with trans-I-ovalbumin conjugate and by enzyme immunoassay using trans-I-beta-galactosidase conjugate. Cross-reactivity studies indicated that the antiserum was highly specific for the tetralin structure and for substitution at the C2 position. The antiserum also selectively discriminated the stereoisomers about the C1-C2 bond. The anti-trans-I serum was used to develop EIA for trans-5-hydroxymethyl-6-hydroxy-2-isopropylamino-1,2,3,4-tetrahydronapht halene- 1-ol (IIb), which exhibited strong beta-stimulating activity fairly selective to tracheal muscle, since it recognized trans-IIb to the same degree as trans-I. The assay could detect as little as 100 pg of this compound. The mean recovery of trans-IIb added to plasma was 105%, and values for plasma trans-IIb determined by this immunoassay correlated well with those determined by gas chromatography-mass spectrometry.
Immunopharmacology 1978 Dec
PMID:Enzyme immunoassay of a beta-adrenergic agent using beta-galactosidase as label. 4 9

The plasmid pBGP120 is a ColE1 derivative that contains elements of the Escherichia coli lac operon and the Tn3 transposon. We have selected and isolated a copy-number mutant of pBGP120. In exponentially growing cultures, the copy-number mutant, pOP1, represents approximately 30% of total intracellular DNA compared to about 5% for pBGP120. Plasmid-encoded beta-galactosidase monomer can represent 50% of newly synthesized protein in cells carrying pOP1. pOP1 is structurally unstable in certain genetic backgrounds and under certain growth conditions, breaking down to a smaller sized plasmid that retains the DNA overproducer phenotype and the Tn3 transposon. The smaller overproducer plasmid, pOP1delta6, is generated by a continuous deletion of sequences located between one end of the Tn3 transposon and a site about 630 nucleotides from the EcoRI site in the beta-galactosidase structural gene of pOP1. pOP1delta6 retains the ColE1 origin of replication but has lost the lac promotor and operator and most of the beta-galactosidase structural gene. pOP1delta6 exists at approximately 210 copies per chromosome in exponentially growing cells.
Proc Natl Acad Sci U S A 1978 Dec
PMID:Isolation and characterization of ColE1-derived plasmid copy-number mutant. 10 93

Drosophila melanogaster cell lines Kc and Ca and clones FC and RF6, cultured in vitro, have no detectable beta-galactosidase (beta-galactoside galactohydrolase, EC 3.2.1.23) activity (as measured by hydrolysis of o-nitrophenyl-beta-D-galoctoside). Ecdysterone, a hormonal steroid of critical importance in insect physiology, clearly induces beta-galactosidase activity in D. melanogaster cells cultured in vitro. Induction occurs in cell lines or clones known to be sensitive to ecdysterone (K, Ca, and Fc) and does not occur in clones known to be resistant to the hormone (RF6). Some properties of the hormone-induced beta-galactosidase activity were studied. The Km for o-nitrophenyl galactoside is 0.35 mM and the Ki for lactose is 12 mM (similar to those of Escherichia coli beta-galactosidase); the activity can be recovered after sodium dodecyl sulfate treatment; the enzyme is a tetramer (Mr of the monomer is 64,000).
Proc Natl Acad Sci U S A 1978 Dec
PMID:beta-Galactosidase is induced by hormone in Drosophila melanogaster cell cultures. 10 99

In Escherichia coli, the wild-type repressor of ebg (evolved beta-galactosidase) enzyme synthesis, specified by the ebgR+ gene, responds very weakly to lactulose (fructose-beta-D-galactopyranoside). Selection for a functional repressor that responds strongly to lactulose as an inducer reveals the existence of ebgR+L mutants, which occur spontaneously at a frequency of about 2 X 10(-10) . EBGR+L mutants are pleiotropic in that they specify ebg repressor with a greatly increased response to lactulose, lactose, galactose-arabinoside and methyl-galactoside as inducers. Selection of ebgR+L mutants is discussed within the framework of directed evolution of a regulatory function.
Genetics 1978 Dec
PMID:Regulation of newly evolved enzymes. IV. Directed evolution of the Ebg repressor. 10 63


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