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 disaccharide lactose is naturally present as a component of foods in milk and dairy products. In the gastrointestinal tract, lactose is hydrolysed by the enzyme beta-galactosidase (lactase) into glucose and galactose. These components are absorbed. In most people lactase activity decreases at the age of approximately 2 years of age. After this lactose intake can cause symptoms of bloating, flatulence, abdominal pain and diarrhoea due to the lactose reaching the large intestine. This phenomenon is called lactose intolerance. It is generally recommended that these people abandon the consumption of milk and dairy products. However, most lactose-intolerant people are able to digest small amounts of milk (approximately 200 ml). They can also consume cheese without (hard and semi-hard cheese) or only low lactose content (only present in 10% of soft cheese). These products are a very important source of calcium.
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PMID:[Lactose in human nutrition]. 978 54

The cladoceran Daphnia pulex is well established as a model for ecotoxicology. Here, we show that D. pulex is also useful for investigating the effects of toxins on the heart in situ and the toxic effects in lactose intolerance. The mean heart rate at 10 degrees C was 195.9+/-27.0 beats/min (n=276, range 89.2-249.2, >80% 170-230 beats/min). D. pulex heart responded to caffeine, isoproteronol, adrenaline, propranolol and carbachol in the bathing medium. Lactose (50-200 mM) inhibited the heart rate by 30-100% (K(1/2)=60 mM) and generated severe arrhythmia within 60 min. These effects were fully reversible by 3-4 h. Sucrose (100-200 mM) also inhibited the heart rate, but glucose (100-200 mM) and galactose (100-200 mM) had no effect, suggesting that the inhibition by lactose or sucrose was not simply an osmotic effect. The potent antibiotic ampicillin did not prevent the lactose inhibition, and two diols known to be generated by bacteria under anaerobic conditions were also without effect. The lack of effect of l-ribose (2 mM), a potent inhibitor of beta-galactosidase, supported the hypothesis that lactose and other disaccharides may affect directly ion channels in the heart. The results show that D. pulex is a novel model system for studying effects of agonists and toxins on cell signalling and ion channels in situ.
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PMID:Lactose causes heart arrhythmia in the water flea Daphnia pulex. 1546 69

Previous studies suggest that, besides the maldigestion of lactose in the small intestine, the colonic processing of lactose might play a role in lactose intolerance. beta-Galactosidase is the bacterial enzyme which catalyzes the first step of lactose fermentation in the colon. We propose a practical method to differentiate and identify bacteria with beta-galactosidase activity in faeces which combines a colony-lift filter assay with X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) as substrate for differentiation and the fluorescent in situ hybridization technique for identification. The method was applied to faeces from lactase non-persistent subjects. After 28 subjects had undergone one glucose and two lactose challenges, consistent intolerant (n=5) and tolerant (n=7) groups were defined according to their symptom scores. Of the 28 faecal samples, 80.6% (mean, SD: 12.1, range: 47.8-100%) of the total cultured bacteria were found to possess beta-galactosidase activity, which indicates that the bacterial beta-galactosidase is abundant in the colon. The tolerant and intolerant groups did not differ in the percentage or composition of the bacteria with beta-galactosidase activity or beta-galactosidase activity in faeces. Results suggest that the percentage or composition of the bacteria with beta-galactosidase activity in faeces do not play a role in lactose intolerance.
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PMID:Identification of bacteria with beta-galactosidase activity in faeces from lactase non-persistent subjects. 1633 43

Lactose malabsorption is a very common condition characterized by intestinal lactase deficiency. Primary lactose malabsorption is an inherited deficit present in the majority of the world's population, while secondary hypolactasia can be the consequence of an intestinal disease. The presence of malabsorbed lactose in the colonic lumen causes gastrointestinal symptoms. The condition is known as lactose intolerance. In patients with lactase nonpersistence, treatment should be considered exclusively if intolerance symptoms are present. In the absence of guidelines, the common therapeutic approach tends to exclude milk and dairy products from the diet. However, this strategy may have serious nutritional disadvantages. Several studies have been carried out to find alternative approaches, such as exogenous beta-galactosidase, yogurt and probiotics for their bacterial lactase activity, pharmacological and non pharmacological strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation. In this review the usefulness of these approaches is discussed and a therapeutic management with a flow chart is proposed.
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PMID:Management and treatment of lactose malabsorption. 1648 16

The research field for applications of lactose hydrolysis has been investigated for several decades. Lactose intolerance, improvement for technical processing of solutions containing lactose, and utilization of lactose in whey are the main topics for development of biotechnological processes. We report here the optimization of a hollow-fiber membrane reactor process for enzymatic lactose hydrolysis. Lactase was circulated abluminally during luminal flow of skim milk. The main problem, the growth of microorganisms in the enzyme solution, was minimized by sterile filtration, ultraviolet irradiation, and temperature adjustment. Based on previous experiments at 23 +/- 2 degrees C, further characterization was carried out at 8 +/- 2 degrees C, 15 +/- 2 degrees C (beta-galactosidase), and 58 +/- 2 degrees C (thermostable beta-glycosidase) varying enzyme activity and flow rates. For a cost-effective process, the parameters 15 +/- 2 degrees C, 240 U/mL of beta-galactosidase, an enzyme solution flow rate of 25 L/h, and a skim milk flow rate of about 9 L/h should be used in order to achieve an aimed productivity of 360 g/(L x h) and to run at conditions for the highest process long-term stability.
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PMID:Optimization of an innovative hollow-fiber process to produce lactose-reduced skim milk. 1689 62

Functional screening studies revealed that Aspergillus carbonarius ATCC6276 produced extracellular beta-galactosidase activity potentially suited for use as a lactase digestive supplement in the treatment of lactose intolerance. The crude preparation contained two beta-galactosidase activities, beta-gal 1 and beta-gal 2, which were separated by ion-exchange chromatography. Both enzymes were purified to homogeneity by a combination of gel filtration, ion-exchange, chromatofocusing and hydrophobic interaction chromatographies. beta-gal 1 and beta-gal 2 displayed differences in molecular mass (110 kDa versus 120 kDa as judged by SDS PAGE) and in a range of additional physicochemical properties. Km values of 83 and 309 mM, respectively, were recorded using lactose as substrate while temperature optima of 55 degrees C versus 65 degrees C were obtained. Unlike current commercialized supplemental lactases, both of the purified enzymes displayed significant stability when exposed to simulated gastric conditions, with beta-gal 1 in particular retaining 70% residual activity after exposure to pH 2.0 in the presence of pepsin for 2 h. Overall the results indicate that the beta-galactosidases of Aspergillus carbonarius ATCC6276, either individually or in combination, may be suitable for use as a digestive supplement for the alleviation of lactose intolerance.
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PMID:Application relevant studies of fungal beta-galactosidases with potential application in the alleviation of lactose intolerance. 1840 43

Lactose malabsorption is a very common condition characterized by intestinal lactase deficiency. Primary lactose malabsorption is an inherited deficit present in the majority of the world's population, while secondary bypolactasia can be the consequence of an intestinal disease. The presence of malabsorbed lactose in the colonic lumen may cause gastrointestinal symptoms. This condition is known as lactose intolerance. Lactase non-persistence is the ancestral state, whilst two single nucleotide polymorphisms in the lactase gene have been associated with lactase persistence. These are C/T 13910 and G/A 22018 substitutions. Lactase persistence, this Mendelian dominant trait, only became advantageous after the invention of agriculture, when milk from domesticated animals became available for adults to drink. Lactase persistence is then strongly correlated with the diary history of the population. Diagnosis is assessed clinically by elimination of dietary lactose or, better, by non-invasive tests including hydrogen breath test and genetic test. In patients with lactase non-persistence, treatment should be considered exclusively if intolerance symptoms are present. In the absence of guidelines, the common therapeutic approach tends to exclude milk and dairy products from the diet. However, this strategy may have serious nutritional disadvantages. Several studies have been carried out to find alternative approaches, such as exogenous beta-galactosidase, yogurt and probiotics for their bacterial lactase activity, strategies that can prolong contact time between enzyme and substrate delaying gastrointestinal transit time, and chronic lactose ingestion to enhance colonic adaptation.
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PMID:Lactose intolerance: a non-allergic disorder often managed by allergologists. 1949 47

The hydrolysis of oligosaccharides and lactose is of great importance to the food industry. Normally, oligosaccharides like raffinose, stachyose, and verbascose which are rich in different plants like soy bean are considered indigestible by the human gut. Moreover, many humans suffer from lactose intolerance due to the absence of effective enzyme that can digest lactose. alpha-Galactosidase can digest oligosaccharides like raffinose, while beta-galactosidases can hydrolyze lactose. Therefore, selection of microorganisms safe for human use and capable of producing high levels of enzymes becomes an attractive task. The objective of this study was to investigate the enhancement of alpha- and beta-galactosidase activity in Lactobacillus reuteri by different metal ions. Ten millimolar of Na(+), K(+), Fe(2+), and Mg(2+) and 1 mM of Mn(2+) were added separately to the growth culture of six strains of L. reuteri (CF2-7F, DSM20016, MF14-C, MM2-3, MM7, and SD2112). Results showed that L. reuteri CF2-7F had the highest alpha- and beta-galactosidase activity when grown in the medium with added Mn(2+) ions (22.7 and 19.3 Gal U/ml, respectively). 0.0274% of Mn(2+) ions lead to 27, 18% enhancement of alpha- and beta-galactosidase activity over the control group, and therefore, it could be added to the growth culture of CF2-7F to produce enhanced levels of alpha- and beta-galactosidase activity. The addition of Fe(2+) led to a significant (P < 0.01) decrease in the activity of both enzymes for most strains. This study shows that modified culture medium with that 0.0274% Mn(2+) can be used to promote the production for alpha- and beta-galactosidase in L. reuteri CF2-7F, which may lead to enhancement of alpha- and beta-galactosidase activity and have a good potential to be used in the food industry.
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PMID:Enhancement of alpha- and beta-galactosidase activity in Lactobacillus reuteri by different metal ions. 1977 68

The LacZ gene encoding beta-galactosidase from Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 (L. bulgaricus) was cloned, sequenced and expressed in Escherichia coli, followed by purification and characterization of the protein. The recombinant enzyme was shown to be a homotetramer and could be distinguished from homologues by its relatively low and broad optimal temperature range, from 35 to 50 degrees C, coupled with an optimal pH of 5.0-5.5. Remarkably, the E491A mutant showed the same optimal temperature, but displayed an optimal pH at 6.5-7.0. Whilst these beta-galactosidases are inhibited by Cu(2+) they require only 1mM Mn(2+) and 1mM Co(2+) for optimal activity and thermostability. The wild-type enzyme was remarkably stable at acid pH values when compared to mutant E491A. Kinetic studies demonstrated that the E491A mutation affected catalysis rather than enzyme affinity. Furthermore, the wild-type protein efficiently cleaved lactose extracted from whey; however, in milk the E491A mutant showed the highest lactose bioconversion rate. Thus, these enzymes are interesting at the industrial level for hydrolysis of lactose extracted from whey or milk, and thus could contribute to overcoming the lactose intolerance problem generated by milk products.
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PMID:Exploring the acidotolerance of beta-galactosidase from Lactobacillus delbrueckii subsp. bulgaricus: an attractive enzyme for lactose bioconversion. 1978 95

Extracellular beta-galactosidase produced by a strain of Aspergillus niger van Tiegh was purified to homogeneity using a combination of gel filtration, ion-exchange, chromatofocusing, and hydrophobic interaction chromatographies. The enzyme displayed a temperature optimum of 65 degrees C and a low pH optimum of between 2.0 and 4.0. The monomeric glycosylated enzyme displayed a molecular mass of 129 kDa and an isoelectric point of 4.7. Protein database similarity searching using mass spectrometry-derived sequence data indicate that the enzyme shares homology with a previously sequenced A. niger beta-galactosidase. Unlike currently commercialised products, the enzyme displayed a high level of stability when exposed to simulated gastric conditions in vitro, retaining 68+/-2% of original activity levels. This acid-stable, acid-active beta-galactosidase was formulated, along with a neutral beta-galactosidase from Kluyveromyces marxianus DSM5418, in a novel two-segment capsule system designed to ensure delivery of enzymes of appropriate physicochemical properties to both stomach and small intestine. When subjected to simulated full digestive tract conditions, the twin lactase-containing capsule hydrolyzed, per unit activity, some 3.5-fold more lactose than did the commercial supplemental enzyme. The acid-stable, acid-active enzyme, along with the novel two-segment delivery system, may prove beneficial in the more effective treatment of lactose intolerance.
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PMID:A novel acid-stable, acid-active beta-galactosidase potentially suited to the alleviation of lactose intolerance. 1980 54


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