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)

The effect of N6,O2'-dibutyryl adenosine 3',5'-cyclic-monophosphate (dbcAMP) on the mobilization of calcium (Ca2+), inorganic phosphate (Pi) and lysosomal enzymes was studied in a bone culture system for 24 h using half calvaria from 6--7 day-old mice. DbcAMP inhibited spontaneous as well as parathyroid hormone-stimulated mineral mobilization. DbcAMP in a concentration of 5 x 10(-4)M also reduced the activities of beta-glucuronidase, beta-galactosidase and acid phosphatase found in the media while the activities of lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were not affected. It is concluded that cAMP is not a stimulator but an inhibitor of bone resorption within the culture period studied (24 h) and that the cyclic nucleotide might interfere with release processes involved in bone resorption.
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PMID:Inhibitory effect of dibutyryl cyclic AMP on the release of calcium, inorganic phosphate and lysosomal enzymes from calvarial bones cultured for 24 hours. 22 6

Ten strains of Propionibacterium shermanii were tested for beta-galactosidase (beta-gal) activity. Of these ten strains, five yielded enhanced enzyme activity when cell suspensions were treated with toluene-acetone; on solvent treatment, the remaining five lost a considerable portion of the activity found in whole-cell suspensions. By using a strain yielding decreased activity upon solvent treatment, explanations for the loss in activity were sought through assays for possible alternative beta-galactoside utilization mechanisms. When this strain was assayed for beta-D-phosphogalactoside galactohydrolase by using orthonitrophenyl-beta-D-galactopyranoside-6-P04 as a substrate, the activity was wither lower or indiffernt as compared with beta-gal activity determined simultaneously. Cell suspensions of P. shermanii 7 and 22 (strains chosen for further work) grown separately on the individual substrates (lactose, glucose, galactose, and sodium lactate) did not show significant differences in beta-gal activity. Optimal temperature for beta-gal activity in untreated and toluene-acetone-treated cell suspensions of strain 7 was 52 C. With strain 22, of the temperatures tested, maximal activity in untreated cell suspensions was noted at 58 C and with solvent-treated cells at 32 C. In the cell-free extract (CFE) system, both strains exhibited maximal activity at 52 C. Optimal pH for untreated and solvent-treated cell suspensions of both strains was around 7.5. In the P. shermanii 22 CFE system, maximal activity occurred at pH 7.0; pH had very little effect on enzyme activity in P. shermanii 7 CFE. Sodium or potassium phosphate buffers in the assay system yielded the best activity. In the CFE system of these two strains, Mn2+ was definitely stimulatory, but in untreated and solvent-treated cell systems of these strains presence or absence of Mn2+ in the assay system had variable effects on enzyme activity. Maximal beta-gal activity was noted in P. shermanii 7 cells harvested after 28 h of growth at 32 C in sodium lactate broth. Sulfhydryl-group blocking agents inhibited enzyme activity in P. shermanii 22 CFE; the inhibition was partly reversed by dithiothreitol.
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PMID:Beta-galactosidase of Propionibacterium shermanii. 23 59

A simple procedure has been devised to isolate beta-galactosidase from jack bean meal. The final preparation gives one major protein banc in disc gel electrophoresis. The substrate specificity of this enzyme toward some natural oligosaccharides, glycoproteins, and sphingoglycolipids has been examined in detail. Among three isomers of N-acetyllactosamine, Galbeta1leads to4GlcNAc; while Galbeta1leads to3GlcNAc was hydrolyzed very slowly. This property can be used to distinguish the galactose linkage in asialo-GM1 (Galbeta1leads to3GalNAcbeta1leads to4Galbeta1leads to4Glcleads toCer) and that in lacto-N-neotetraosylceramide (Galbeta1leads to4GlcNAcbeta1leads to 3Galbeta1leads to4Glcleads toCer). For hydrolyzing glycolipids, the effect of sodium taurodeoxycholate and sodium taurochenodeoxycholate on the rate of hydrolysis was carefully examined. This enzyme hydrolyzes lactosylceramide and asialo-GM1 faster than GM1. These results suggest that in addition to the type and linkage of the penultimate sugar unit, the sugar unit at the distal position of the saccharide chain also affects the hydrolysis rate. It also readily liberates 80% D-galactosyl units from asialo alpha1-acid glycoprotein. Escherichia coli beta-galactosidase on the other hand cannot hydrolyze asialo-alpha1-acid glycoprotein, lactosylceramide, GM1, asialo-GM1, and lacto-N-neotetraosylceramide. The molecular weight of this enzyme is about 75,000 and the isoelectric point is pH 8.0. With p-nitrophenyl beta-D-galactopyranoside as substrate, optimal activity occurs at pH 2.8 with glycine-HCl buffer and at pH 3.5 with citrate-phosphate buffer. With lactose as substrate, the pH optimum in these two buffers are 2.8 and 4.0, respectively. Km values for p-nitrophenyl beta-D-galactopyranoside, o-nitrophenyl beta-D-galactopyranoside and lactose are 0.51 mM, 0.63 mM, and 12.23 mM, respectively. Many inhibitors for this enzyme including inorganic ions, monosaccharides, and glycosides are investigated. In contrast to E. coli beta-galactosidase, jack bean beta-galactosidase is not inhibited by p-aminophenyl thio-beta-D-galactopyranoside.
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PMID:Isolation and characterization of jack bean beta-galactosidase. 23 49

The effect of pH, carbon sources, and some organic substances on the biosynthesis of beta-galactosidase was studied in Alternaria tenuis on a defined medium that had been optimized by the method of mathematical planning of experiments. Optimal conditions for the production of the enzyme and its liberation into the cultural broth were maintained by adding 2 per cent soya flour to the medium and 0.1 M phosphate-citrate buffer pH 3.0. The production of the enzyme was increased by 3 to 4 times. The biosynthesis of beta-galactosidase by Alternaria tenuis is of an induced nature.
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PMID:[Factors influencing the biosynthesis of beta-galactosidase in Alternaria tenuis]. 24 Jan 5

The mechanisms for transport and hydrolysis of lactose were investigated in five cariogenic strains (HS6, AHT, FA1, NCTC 10449, and SL1) representing the four serogenetic groups of Streptococcus mutans. The systems for transport and hydrolysis of lactose had the characteristics of a phosphoenolpyruvate (PEP)-dependent lactose (Lac) phosphotransferase (PT) system and phospho-beta-galactosidase (P-beta-gal), respectively, in all strains tested, except strain HS6. Decryptified cells required PEP and Mg(2+) for transport of the non-metabolizable model beta-galactosides o-nitrophenyl-beta-d-galactopyranoside (ONPG) and thiomethyl-beta-d-galactopyranoside (TMG). Substitution of 2-phosphoglycerate (2-PG) for PEP also stimulated the Lac PT system. Other potential high-energy phosphate donors (adenosine tri-, di-, and monophosphates and guanosine triphosphate) did not stimulate the Lac PT system. Sodium fluoride had no effect upon the PEP-dependent Lac PT system in decryptified cells with PEP as the energy source; however, when 2-PG was used as the energy source, F(-) inhibited ONPG phosphorylation. With intact cells which must generate PEP endogenously, the presence of F(-) in concentration >/= 10 mM completely inhibited the Lac PT system, presumably through inhibition of 2-PG hydrolyase (EC 4.2.1.11; enolase). Both intact and decryptified cells accumulated a phosphorylated derivative of TMG that behaved chromatographically as TMG-phosphate. After alkaline phosphatase treatment, the derivative had an R(f) identical to that of TMG. No beta-galactosidase (beta-gal) activity was detected with ONPG as the substrate; hydrolysis occurred only when ONPG-6-phosphate was supplied as the substrate. Strain HS6 apparently transported lactose by an active transport-type system in which the accumulated intracellular product was the free disaccharide based on the following criteria: (i) ONPG transport and hydrolysis in decryptified cells was not stimulated by PEP; (ii) ONPG hydrolysis occurred in the absence of PEP; and (iii) ONPG-6-phosphate was not hydrolyzed. These data indicate that, in all strains tested except strain HS6, lactose transport was mediated by a PEP-dependent Lac PT system, resulting in accumulation of lactose-phosphate that was hydrolyzed by an enzyme similar to the P-beta-gal of group N streptococci and Staphylococcus aureus; conversely, strain HS6 transported and hydrolyzed lactose by a PEP-independent transport system and beta-gal, respectively.
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PMID:Involvement of phosphoenolpyruvate in the catabolism of caries-conducive disaccharides by Streptococcus mutans: lactose transport. 24 29

The technique of affinity chromatography has been used in the partial purification of complementable fractions and complemented enzyme of beta-galactosidase from Escherichia coli mutant M15. The crude extract of mutant M15 was incubated with fragment CM-B. The complemented enzyme and complementable fractions were passed through a small column of p-aminophenyl-beta-D-thiogalactoside to which inhibitors had been covalently attached. A high percentage of the nonspecific protein passed directly through the affinity column while the specific enzymatic protein remained bound to the gel. Phosphate buffer with NaCl was used to elute the complementable fractions from the column. Sodium borate buffer was used to elute the bound complemented enzyme from the affinity support. The results of this study show that 100% of the complemented enzyme was bound to the column. The partially purified enzyme had the same position in disc gel electrophoresis as beta-galactosidase from E. coli.
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PMID:Complementable fraction and complemented enzyme of mutant M15 from Escherichia coli: partial purification by affinity chromatography. 32 18

Salmonella typhimurium does not produce alkaline phosphatase (nor beta-galactosidase). Nevertheless, it has the function of the phoR+ regulatory gene but lacks the function of the lacI+ regulatory gene. Several periplasmic proteins are derepressed when cells of S. typhimurium are starved for inorganic phosphate. The role of phoR is discussed.
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PMID:Repression of alkaline phosphatase in Salmonella typhimurium carrying a phoA+ phoR- episome from Escherichia coli. 78 59

In view of recent conflicting reports from two laboratories, activities of lactosylceramide beta-galactosidase were reinvestigated in detail in brains and livers of normal individuals and of patients with globoid cell leukodystrophy or GM1-gangliosidosis. Both sets of the apparently totally contradictory results were readily reproduced simply by using the different assay systems of the respective laboratories. With our own assay system, hepatic lactosylceramide beta-galactosidase appeared deficient only in Gm1-gangliosidosis, while it appeared deficient only in globoid cell leukodystrophy when the assay system of Wenger et al. (Wenger, D.A., Sattler, M., Clark, D., and McKelvey, H. (1974) Clin. Chim. Acta 56, 199-206) was used. Analyses of individual constitutents in the two assay systems revealed their complex effects on measured activities of the enzyme. The findings were strongly indicative of the existence of two genetically distinct lactosylceramide-cleaving enzymes. One enzyme (lactosylceramidase I) may be identical with galactosylceramide betal-galactosidase, and the other (lactosylceramidase II) is closely related to nonspecific 4-methylumbelliferyl beta-galactosidase. Normal human brain contains mostly lactosylceramidase I, while normal liver contains predominantly lactosylceramidase II. Lactosylceramidase I is genetically lacking globoid cell leukodystrophy, and lactosylceramidase II in GM1-gangliosidosis. Lactosylceramidase I is activated by either pure or crude taurocholate and by oleic acid and is only slightly activated by chloride ions. Lactosylceramidase II is activated by crude taurocholate but not by pure taurocholate. As activators, oleic acid is less effective and chloride more effective than for lactosylceramidase I. Citrate-phosphate buffer is more favorable to lactosylceramidase I than citrate buffer, while lactosylceramidase II responds in reverse. The standard assay system used by Wenger et al. determines almost exclusively lactosylceramidase I, while our own standard system is optimal for lactosylceramidase II and is less favorable for lactosylceramidase I. With a highly purified human hepatic beta-galactosidase preparation, exxentially free of galactosylceramide beta-galactosidase activity, lactosylceramide-cleaving activity determined by the Wenger system was less than 2 per cent of that determined by our system. If lactosylceramide beta-balactosidase assays are to be used for diagnosis of globoid cell leukodystrophy, it is absolutely essential to use an appropriate assay system in order to avoid errors of serious consequences.
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PMID:Lactosylceramide beta-galactosidase in human sphingolipidoses. Evidence for two genetically distinct enzymes. 80 71

The buoyant densities of mouse immunoglobulins were determined by isopycnic centrifugation in phosphate-buffered cesium chloride using beta-galactosidase as marker. The buoyant densities of IgG, TEPC 15 IgA, secreted IgM, and MOPC 104E IgM were consistent with their carbohydrate contents both in the presence and the absence of the nonionic detergent, Nonidet P-40. Intracellular IgM from spleen cell lysates had a buoyant density corresponding to a carbohydrate content of 6%. Membrane IgM from detergent lysates of spleen cells was less dense than either intracellular or secreted IgM in the presence of detergent. The IgD-like membrane molecules were more dense than membrane IgM.
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PMID:Density differences between membrane and secreted immunoglobins of murine splenocytes. 83 75

The determination of various reaction constants yields the following assay for the photometric evaluation of acid beta-galactosidase (measurement of the azoindoxyl dye at 540 nm after extraction with dimethylformamide or -acetamide): 1.5 mM 5-Br-4-Cl-3-indolyl-beta-D-galactoside (1 mg dissolved in 0.05 ml dimethylformamide) and 0.01-0.015 ml hexazotized p-rosaniline/ml in 0.1 M citric acid-phosphate buffer, pH 4. By means of this procedure it becomes evident that the activity of the enzyme differs considerably in various rat organs; NaCl does not influence acid beta-galactosidase. -- Similar results were obtained with the indigogenic method; indigo can be dissolved and measured photometrically as the azoindoxyl dye. The enzyme is suppressed by high concentrations of hexazotized p-roaniline to 50%; low concentrations do not inhibit; the same is true for ferricyanide-ferrocyanide employed in the indigogenic media. -- The effect of glutar- and formaldehyde on acid beta-galactosidase cannot be investigated with the azoindoxyl reaction since the azoindoxyl dye partially withstands extraction from fixed blocks of tissue. On the basis of the biochemical findings the azoindoxyl technique can be recommended for the histochemical demonstration of acid beta-galactosidase: 7.5 mg (1.5 mM) 5-Br-4-Cl-3-indolyl-beta-D-galactoside (dissolved in 0.25 ml dimethylformamide) and 0.05-0.15 ml hexazonium-p-rosaniline in 10 ml 0.1 M citric acid-phosphate buffer, pH 4. After incubation the sections can be treated with osmium tetroxide followed by dehydration and mounting in resins or can be mounted without prior osmification of the azoindoxyl dye in glycerin jelly. The osmium chelate resists treatment with organic solvents; the stability of the chelate depends on the concentration of hexazotized p-rosaniline. After fixation in glutaraldehyde or in a mixture of form- and glutaraldehyde acid beta-galactosidase can be exactly localized in the lysosomes of many rat organs. In comparison with the indigogenic, the metal precipitation and the simultaneous azocoupling reactions for the in situ detection of acid beta-galactosidase the azoindoxyl procedure is superior if fixed material is used; it is equivalent or inferior in connection with membrane technique. The biochemical azoindoxyl assay represents a useful method for combined qualitative and quantitative studies of acid beta-galactosidase.
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PMID:[Azoindoxyl methods for the investigation of hydrolases. II. Biochemical and histochemical studies of acid beta-galactosidase (author's transl)]. 84 61


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