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)

Activities of maltase, sucrase, lactase and acid-beta-galactosidase were studied in jejunum and ileum of term rat fetuses obtained by cesarian section. Female rats were either untreated or injected daily in the last (3rd) week of pregnancy with cortisone acetate (10 or 50 mg/100 g body weight) or L-triiodothyronine (20 or 50 microgram/100 g body weight). Two other control groups were injected with appropriate solvents. Cortisone or T3 treatment to mothers increased sucrase and maltase activity in jejunum and ileum of the offspring. Generally, higher doses of hormone were more effective. Lactase activity was increased by 25% in the jejunum by the higher dose of cortisone. Both doses of cortisone increased ileal lactase. Jejunal acid-beta-galactosidase activity was decreased in fetuses of T3-treated mothers.
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PMID:Effect of cortisone or L-triiodothyronine administration to pregnant rats on the activity of fetal intestinal disaccharidases and lysosomal acid beta-galactosidase. 41 95

Lactase (beta-galactosidase) was attached to the inner surface of nylon tubing. Tubes of various lengths were used to bring about the hydrolysis of o-nitrophenyl-beta-D-galactoside and of lactose in skim milk. The results with the former substrate were analyzed in the light of a theoretical treatment of Kobayashi and Laidler (Biotechnol. Bioeng., 16, 99, 1974), with the conclusion that the reaction is intermediate between diffusion-free and completely diffusion-controlled behavior. The results with skim milk show that with a single 46 m tube and continuous circulation, 90% of the lactose is removed within 20 hr. A battery of ten such tubes, with single passage, at a flow rate of 2 cm/sec, would remove more than 99% of the lactose in less than 40 min.
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PMID:Hydrolysis of D-galactosides in an open tubular lactase reactor. 104 83

The longitudinal distribution of various enzymes along the human small intestine was studied by analysis of biopsies from different parts of the small intestine, obtained from 13 patients during shunt-operation for severe obesity. Alkaline phosphatase and 3 glycolytic enzyme activities studied were rather uniformly distributed along the small intestine. Acid beta-galactosidase and hetero beta-galactosidase activities were highest in the proximal small intestine with a gradual decline throughout the intestine. The activity in the distal ileum was about half of the maximum activity. Maltase, isomaltase, sucrase, and trehalase activity had a broad maximum in the proximal and middle small intestine with a rather sharp decrease in the distal ileum. Lactase activity had a more pronounced maximum in the middle intestine with a pronounced decrease towards the proximal and distal ends. The disaccharidase activities in surgical biopsies taken 5 cm distal to the ligament of Treitz were about 10% higher than in peroral biopsies taken just at the ligament.
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PMID:Distribution of disaccharidases, alkaline phosphatase, and some intracellular enzymes along the human small intestine. 117 59

Lactase-phlorizin hydrolase is a disaccharidase present in the small intestine of mammals. This enzyme has two active sites, one being responsible for the hydrolysis of lactose. Lactase activity is thought to be selective towards glycosides with a hydrophilic aglycon. In this work, we report a systematic study on the importance of each hydroxyl group in the substrate molecule for lactase activity. For this purpose, all of the monodeoxy derivatives of methyl beta-lactoside and other lactose analogues are studied as lactase substrates. With respect to the galactose moiety, it is shown here that HO-3' and HO-2' are necessary for hydrolysis of the substrates by lactase. Using these chemically modified substrates, it has been confirmed that lactase does not behave as a typical beta-galactosidase, since it does not show an absolute selectivity with respect to substitution and stereochemistry at C4' in the galactose moiety of the substrate. However, the glucose moiety, in particular the HO-6, appears to be important for substrate hydrolysis, although none of the hydroxyl groups seemed to be essential. In order to differentiate both activities of the enzyme, a new assay for the phlorizin-hydrolase activity has also been developed.
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PMID:Substrate specificity of small-intestinal lactase. Assessment of the role of the substrate hydroxyl groups. 139 15

Gastric intubation was adopted to examine the effect of continuous nutrient supply on digestive development of the pig during the immediate post-weaning period. The 14 d-weaned animals were slaughtered at 3, 5 and 7 d post-weaning (3W, 5W and 7W respectively) and the suckled animals were slaughtered at 14 and 22 d of age (14SR and 22SR respectively). The weight of the pancreas (g/kg bodyweight) was significantly greater (P less than 0.05) in the 5W and 7W groups, as was the weight of large intestine (g/kg) in all weaned groups (P less than 0.01) compared with sow-reared pigs. The stomach weight (g/kg) tended to be greater in the weaned groups. Weaning, in conjunction with a continuous nutrient supply, did not significantly alter the time-related changes in the weight of the small intestine (SI) or the SI mucosa, although both variables tended to be lowest in the 3W group. However, there was a 20% reduction in the protein content of the mucosa within the first 3 d post-weaning (P less than 0.01) which persisted during the 7 d experimental period. Lactase, (beta-galactosidase; EC 3.2.1.23) activity (mumol/g protein and mol/d) of the 7W group was reduced to approximately 40% of the 22SR value. Hence, continuous nutrient supply may have delayed, but did not prevent, the loss of lactase activity at weaning. The activity of sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) was significantly higher in 22SR compared with 14SR animals. Sucrase activity in weaned pigs was intermediate to the values for sow-reared pigs whereas maltase (alpha-glucosidase; EC 3.2.1.20) and glucoamylase (glucan 1,4-alpha-glucosidase; EC 3.2.1.3) were significantly increased in relation to their sow-reared counterparts. Continuous nutrient supply did not prevent the reduction in villous height and the crypt hypertrophy associated with weaning. The results of the present study suggest that there may be some degree of interaction between nutrient intake and gut development during the immediate post-weaning period but that there is also a component of the adaptive response which is independent of nutrient intake. They confirm the rapid substrate induction of the brush-border glucoamylases and indicate the importance of considering total as well as specific enzyme activity for satisfactory interpretation of changes in digestive function.
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PMID:Digestive development of the early-weaned pig. 1. Effect of continuous nutrient supply on the development of the digestive tract and on changes in digestive enzyme activity during the first week post-weaning. 190 70

Lactase deficient subjects, who form the bulk of the world population, absorb yogurt lactose because the bacteria used for fermentation produce beta-galactosidase. From a milk fermented by these bacteria and dried by a temperature-controlled process a power could be obtained which possess residual lactase activity but, unlike yogurt, does not need storage at low temperature. The lactose of this fermented powdered milk is perfectly absorbed, as proved by hydrogen respiratory tests performed in 35 lactose intolerant African subjects living in isolated villages. In 25 malnourished children under 3 years of age, this milk allowed renutrition without inducing diarrhoea--a result which could not have been obtained with ordinary milk in two-thirds of the cases. This type of food is potentially valuable to feed the large population of the third world.
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PMID:[Use of a fermented powdered milk in malnourished or lactose intolerant children]. 213 60

Lactase-deficient subjects absorb lactose in yogurt more effectively than lactose in other dairy products. However, as all previous studies were performed without a double-blind design and only after a single ingestion of the test product, the mechanism of this enhanced absorption remains unclear. The aims of this double-blind study were 1) to evaluate lactose absorption after prolonged ingestion of yogurt and fermented-then-pasteurized milk (FPM) and 2) to assess the modification of the lactase activity of the duodenal mucosa. In 16 lactase-deficient subjects we confirmed that yogurt enhances lactose digestion, this beneficial effect being destroyed by pasteurization. Moreover, the long-term (8 d) ingestion of either yogurt or FPM does not modify the results of hydrogen breath tests in comparison with a 24-h ingestion. The mucosal lactase (Dahlquist method) and beta-galactosidase (ONPG method) activities were not significantly modified by yogurt or FPM ingestion. These results suggest that in lactase-deficient subjects no adaptation occurs after eating yogurt or FPM and that the increased lactose absorption in yogurt must be mainly related to an intraluminal process.
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PMID:Yogurt and fermented-then-pasteurized milk: effects of short-term and long-term ingestion on lactose absorption and mucosal lactase activity in lactase-deficient subjects. 249 32

1. Intestinal structure, lactase (beta-galactosidase; EC 3.2.1.23) activity and alkaline phosphatase activity have been determined in mouse jejunal and ileal tissues before and during infection with the intestinal parasite Nematospiroides dubius. 2. Oral infection with small numbers of N. dubius larvae caused villus height, crypt depth and enterocyte migration rate to increase in the mouse jejunum. None of these effects occurred in ileal tissue. 3. Lactase activity also increased in jejunal, but not ileal, tissue of infected mice. This increase was associated with a doubling of the rate at which activity appeared in the brush-border membrane of enterocytes during migration over the basal regions of jejunal villi. Alkaline phosphatase activity in jejunal tissue remained unchanged in infected mice. 4. Attention is drawn to the fact that this is the first occasion when crypt cell hyperplasia has been found to be positively correlated with an increase in lactase activity and a decrease in cytotoxic/suppressor T-cells. Further work is needed to establish the primary cause of these effects.
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PMID:Intestinal infection with Nematospiroides dubius selectively increases lactase expression by mouse jejunal enterocytes. 250 31

Exogenous, microbial beta-D-galactosidases are capable of effecting hydrolysis of lactose in situ in the gastrointestinal tract of lactase-deficient subjects when given as replacement therapy at mealtime. As its digestion products-glucose and galactose-are known to inhibit lactose hydrolysis in vitro, the effect of adding excess monosaccharide to milk on the hydrolytic efficiency of a beta-galactosidase from Aspergillus niger in adult lactose-malabsorbers was tested. Subjects were studied with 360-ml volumes of milk containing 18 g of carbohydrate. This was administered as intact milk, as lactose-prehydrolyzed milk, and as milk to which 399 mg of Lactase N was added within 5 minutes of consumption. This latter Lactase N-treated milk was administered alone and with graded levels of glucose-9, 18, and 36 g-and with similar doses of galactose. The Lactase N enzyme alone at mealtime reduced breath H2 production by 68% as compared to intact milk. The addition of monosaccharides produced no change in the apparent hydrolytic efficiency of the Lactase N in situ. Thus, product inhibition is unlikely to be the basis for the limited efficiency of intraintestinal hydrolysis of milk lactose by the enzyme from A niger.
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PMID:The effect of the digestion products of lactose (glucose and galactose) on its intraintestinal, in vivo hydrolysis by exogenous microbial beta-D-galactosidase. 309 Jan 30

Lactase-deficient subjects more effectively digest lactose in yogurt than lactose in other dairy products, apparently due to yogurt microbial beta-galactosidase (beta-gal) which is active in the GI tract. We evaluated the effects of buffering capacity of yogurt, gastric pH, and microbial cell disruption on beta-gal activity and lactose digestion. Three times more acid was required to acidify yogurt than to acidify milk. Yogurt beta-gal was stable at pH 4.0 but inactivated at lower pH. When yogurt was sonicated to disrupt microbial cell structure, only 20% activity remained after incubation at pH 4.0 for 60 min. In vivo gastric pH remained greater than 2.7 for 3 h after ingestion of yogurt. Acidified milk alone or with disrupted yogurt microorganisms caused twice as much lactose malabsorption as did acidified milk containing intact yogurt microorganisms. The results provide a possible explanation for the survival of beta-gal activity from yogurt in the GI tract.
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PMID:Lactose digestion by yogurt beta-galactosidase: influence of pH and microbial cell integrity. 310 80


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