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)

Three beta-N-acetylhexosaminidases [EC 3.2.1.52] and one beta-galactosidase [EC 3.2.1.23] were purified from the culture filtrate of streptococcus 6646 group K by a combination of column chromatographies on p-aminophenyl beta-D-thiogalactopyranoside-substituted Sepharose and N-(paminophenyl)oxamic acid-substituted Sepharose. These beta-N-acetylhexosaminidases showed optimal activities between pH 5.0 and 5.5 and could hydrolyze synthetic and glycopeptidic substrates. Glycolipids such as GM2, asialo-GM2, and globoside I were no susceptible to these beta-hexosaminidases. beta-Galactosidase, which was purified more than 11,000-fold, had a substrate specificity rather similar to that of beta-galactosidase from E. coli. This enzyme was inhibited by EDTA and activated by Mn2+, Ca2+, and Mg2+. Problems pertinent to the application of affinity chromatography to the purification of glycosidases are also discussed.
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PMID:Purification and characterization of beta-N-acetylhexosaminidases and beta-galactosidase from Streptococcus 6646 K. 0 84

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.
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PMID:Characterization of beta-galactosidase from a special strain of Aspergillus oryzae. 1 18

beta-Galactosidase (EC 3.2.1.23) from fungus Curvularia inaequalis was modified by active brilliant orange KH and adsorbed on DEAE-Sephadex A-50. The lactose hydrolysis was studied in a continous flow on the column packed with the immobilized enzyme. The pH and temperatures optima for the substrate hydrolysis by the immobilized enzyme were shown to remain unchanged. A certain destabilizing effect of the matrix on the enzyme resistance to hear denaturation was observed. The activation parameters of denaturation of the native enzyme as well as those of the dye-modified and immobilized preparations were determined.
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PMID:[Enzymatic properties of immobilized beta-galactosidase from Curvularia inaequalis]. 1 60

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.
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PMID:A pH-conditional mutant of Escherichia coli. 2 35

beta-Galactosidase activity was investigated in one case of juvenile GM1-gangliosidosis. This patient exhibited normal activity of the neutral form of beta-galactosidase (measured as beta-glucosidase activity) and normal pH curve of residual acid beta-galactosidase activity in leucocytes and fibroblasts. A shift towards more neutral pH optimum was seen in the beta-galactosidase enzyme occurring in serum. The communication also presents a study of the relationship of the different beta-galactosidases in human liver using isolated urine oligosaccharide from this patient as a beta-galactoside substrate. The other natural beta-galactoside substrates used in this investigation were different oligosaccharides, one glycopeptide and ceramide-beta-galactosidase. The beta-galactosidase forms with acidic pH optimum towards synthetic substrate (A forms) exhibit activity towards the natural substrate (except ceramide-beta-galactoside). The "neutral" beta-galactosidase with broad substrate specificity (B form) which includes beta-glucosides had no activity towards the natural substrates used. It could also be shown that the activity towards ceramide-beta-galactoside was a third type of beta-galactosidase different from A and B forms.
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PMID:beta-D-galactosidase activities in juvenile GM1-gangliosidosis. 3 Oct 52

beta-Galactosidase (EC 3.2.1.32) was purified 80-fold from the yeast Kluyveromyces lactis induced for this enzyme by growth on lactose. When the purified enzyme was subjected to electrophoresis on an acrylamide gel in the presence of sodium dodecyl sulfate, one protein with an apparent molecular weight of 135,000 was observed. The enzyme has a sedimentation coefficient of 9.6S. This beta-galactosidase and the one from Escherichia coli are not antigenically related. Maximal enzyme activity requires Na+ and Mn2+ and a reducing agent. beta-Galactosidase has Km values of 12 to 17 and 1.6 mM for lactose and o-nitrophenyl-beta-D-galactoside, respectively. The hydrolase and transgalactosylase activities of the enzyme are similar to those of E. coli beta-galactosidase.
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PMID:Purification and properties of an inducible beta-galactosidase isolated from the yeast Kluyveromyces lactis. 3 53

A 28-month-old child was found to have several clinical features of lysosomal storage diseases, including: coarse facies, hepatosplenomegaly, lumbar kyphosis due to hypoplastic beaked L1 and L2 vertebral bodies, vacuolated lymphocytes in blood smears and rare foamy hystiocytes in bone marrow. However, no signs of neurological or ocular abnormalities were detected. A beta-galactosidase deficiency was demonstrated in leukocytes and cultured skin fibroblasts, with a residual activity toward 4-methylumbelliferyl-beta-galactopyranoside ranging between 5 and 15% of the normal mean. Normal activities were found for several other lysosomal acid hydrolases. beta-Galactosidase activities in leukocytes and cultured skin fibroblasts from both parents were within the normal ranges. The patient seems to represent an atypical expression of acid beta-galactosidase deficiency, since his clinical picture does not exaclty correspond to that of either the two classical types of GM1-gangliosidosis or other atypical patients reported in the literature havining beta-galactosidase deficiency.
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PMID:Atypical expression of beta-galactosidase deficiency in a child with Hurler-like features but without neurological abnormalities. 9 48

1. Human liver acid beta-galactosidase A2 and A3 were isolated by chromatography on concanavalin A-Sepharose 4B, Sepharose 6B, and Sepharose 4B-6-aminohexyl 1-thio-beta-D-galactopyranoside. beta-Galactosidase A2 and A3 were purified to final specific activities of 45.5 and 20.6 mumol/min per mg respectively with 4-methylumbelliferyl beta-D-galactopyranoside as substrate. 2. Form A2 had a mol.wt. of 150000 +/- 15000 (gel filtration) and appeared as a single band of protein (mol.wt 65000 +/- 1000) on electrophoresis in the presence of sodium dodecyl sulphate. 3. Form A3 had a mol.wt. (gel filtration) of 660000 +/- 66000. On electrophoresis in the presence of sodium dodecyl sulphate, form A3 appeared as a major band of protein (72% of total) of mol.wt. 65000 +/- 1000 and minor protein bands of mol.wt. 44000 +/- 1000 and 26,000 +/- 1000 and 22000 +/- 1000. 4. Gel-filtration chromatography of purified beta-galactosidase A3 generated approximately equal amounts of forms A3 and A2. beta-Galactosidase A1 was not detected by gel-filtration chromatography of partially or highly purified preparations of forms A2 and A3. 5. Both forms A2 and A3 had identical isoelectric points of 4.42 +/- 0.02. The data suggest that forms A2 and A3 are dimeric and multimeric forms of beta-galactosidase A1. 6. Amino acid analysis of beta-galactosidase A2 gave a ratio of acidic to basic amino acids of 2.6:1. 7. beta-Galactosidase A2 contained 7.5% carbohydrate by weight and sialic acid, D-galactose, D-glucosamine and D-mannose were present in the molar proportions 1.1:1.0:1.7:2.7.
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PMID:Characterization of purified human liver acid beta-D-galactosidases A2 and A3. 10 12

A clinical description of an apparently classical case of type 1 GM1 gangliosidosis is presented. The patient was the first-born child of first cousins. She was diagnosed at 6 weeks and died at 6 months. beta-Galactosidase activity was deficient in cultured fibroblasts using [3H]GM1 ganglioside and [3H]ceramide-lactose as substrates. Genetic complementation studies performed after cell fusion between cultured fibroblasts from the patient and from two other type 1, one type 2, and one juvenile GM1 gangliosidosis strain were positive with all strains. Subsequent studies revealed an increased excretion of a sialic acid-containing hexasaccharide in the patient's cells. Parents' fibroblasts contained normal levels of beta-galactosidase. The case emphasizes the variability of the clinical expression in sialidosis and the importance of demonstrating a primary gene defect in establishing a diagnosis of an inborn error or metabolism.
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PMID:Infantile sialidosis: a phenocopy of type 1 GM1 gangliosidosis distinguished by genetic complementation and urinary oligosaccharides. 11

The ability of two different enzyme-antibody conjugates to detect specific antibodies has been compared. beta-Galactosidase was conjugated to antibodies raised against rabbit Fc fragments using m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS). Horseradish peroxidase (HRP) was conjugated to part of the same batch of antibodies using the periodate method. The beta-galactosidase and HRP labels enabled detection of approximately 8 fmoles and 4 fmoles respectively of human growth hormone (HGH) antibodies, when their enzyme activities were measured spectrophotometrically. The detection limit of the beta-galactosidase label was increased 4-fold when a fluorimetric detection system was employed.
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PMID:A comparison of the ability of beta-galactosidase and horseradish peroxidase enzyme-antibody conjugates to detect specific antibodies. 11 16


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