Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activities of the brush border enzymes alkaline phosphates, leucine aminopeptidase and lactase and the lysosomal enzymes alpha-mannosidase and beta-N-acetylglucosaminidase increased in the serum of newly-born lambs fed colostrum. Feeding lipid and protein components of colostrum and bovine serum resulted in enzyme responses similar to those observed after feeding colostrum. Activities of each of the enzymes increased in mesenteric lymph collected from newly-born lambs when immunoglobulins were being absorbed from the jejunum and ileum.
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PMID:Intestinal brush border and lysosomal enzymes and immunoglobulin absorption in the newly-born lamb. 41 Apr

The effect of intestinal bacterial over-growth on brush border hydrolases and brush border glycoproteins was studied in nonoperated control rats, control rats with surgically introduced jejunal self-emptying blind loops, and rats with surgically introduced jejunal self-filling blind loops. Data were analyzed from blind loop segments, segments above and below the blind loops, and three corresponding segments in the nonoperated controls. Rats with self-filling blind loops had significantly greater fat excretion than controls and exhibited significantly lower conjugated:free bile salt ratios in all three segments. Maltase, sucrase, and lactase activities were significantly reduced in homogenates and isolated brush borders from the self-filling blind loop, but alkaline phosphatase was not affected. The relative degradation rate of homogenate and brush border glycoproteins was assessed by a double-isotope technique involving the injection of d-[6-(3)H]glucosamine 3 h and d-[U-(14)C]glucosamine 19 h before sacrifice, and recorded as a (3)H:(14)C ratio. The relative degradation rate in both homogenate and brush border fractions was significantly greater in most segments from rats with self-filling blind loops. In the upper and blind loop segments from rats with self-filling blind loops, the (3)H:(14)C ratios were higher in the brush border membrane than in the corresponding homogenates, indicating that the increased rates of degradation primarily involve membrane glycoproteins. Incorporation of d-[6-(3)H]glucosamine by brush border glycoproteins was not reduced in rats with self-filling blind loops, suggesting that glycoprotein synthesis was not affected. Polyacrylamide gel electrophoresis of brush border glycoproteins from the contaminated segments indicated that the large molecular weight glycoproteins, which include many of the surface hydrolases, were degraded most rapidly. Brush border maltase, isolated by immunoprecipitation, had (3)H:(14)C ratios characteristic of the most rapidly degraded glycoproteins. The results indicate that bacteria enhance the destruction of intestinal surface glycoproteins including disaccharidases. Since alkaline phosphatase, a glycoprotein, is not affected, the destruction is selective and presumably involves only the most exposed membrane components.
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PMID:Pathogenesis of mucosal injury in the blind loop syndrome. Brush border enzyme activity and glycoprotein degradation. 41 Aug 30

1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12--37). 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100000 X g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counter-parts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5--6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of the lysosomal origin, but have characteristics of membrane-bound enzymes. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.
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PMID:Development of intestinal brush border membrane proteins in the rat. 41 9

The disaccharidase activities in small intestinal biopsies were related to the morphology of the mucosa and the ages of 63 patients with cystic fibrosis and 177 healthy control subjects of Caucasian origin. In patients with CF and in the healthy control subjects under 5 years of age with normal intestinal mucosa, no low lactase activity was found. In those patients with CF who were over 5 years of age, one group had high and one group had low lactase activity, as occurs in healthy Caucasian control subjects of the same age. This finding supports the view that in patients with CF, lactase deficiency is not related to the disease entity. In patients with or without CF who had the same degree of mucosal atrophy, the decrease of disaccharidase activities followed the same pattern, indicating that enzyme activities are affected to the same extent by the damage of the mucosa. In patients with CF with pancreatic insufficiency, the disaccharidase activities were significantly (P less than 0.001) higher when compared to those in control subjects of the same age and ethnic group, although the increase was not uniform in all patients with cystic fibrosis.
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PMID:Disaccharidase activities in small intestinal mucosa in patients with cystic fibrosis. 41 96

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

The changes with age of intestinal mucosa, protein, lactase, maltase and sucrase were followed in the piglet between day 105 of gestation and 8 weeks after birth. Lactase and maltase activities appeared during fetal life in the whole of the small intestine. Activity of sucrase was recorded after the 1st postnatal week. Lactase activity was high at birth and reached a maximum at 1 week (X 2.5); maltase activity which was low at birth increased to the 8th week (X 143). Activities of all enzymes were low in the duodenum; lactase was most active in the jejumum. Similar activities of maltase and sucrase were found in the two distal parts of the small intestine. Specific activity (related to protein content) of lactase reached a maximum at the end of the 1st week after birth and decreased afterwards. Specific maltase and sucrase activities were higher in the 2nd week, decreased between the 2nd and 4th week and increased afterwards (maltase) or decreased to the 6th--8th week (sucrase).
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PMID:Development of digestive enzymes in the piglet from birth to 8 weeks. II. Intestine and intestinal disaccharidases. 41 3

The circadian rhythms in the activities of maltase and lactase of the small intestine were examined at various stages of postnatal development in rats. When the rats were fed ad libitum, no circadian change in the enzyme activities was found during the suckling period or the weaning period. However, several days after the time of weaning, the enzymes showed the same circadian changes as in adult rats with higher activities at night. After weaning, when the rats were fed only during the daytime, the phase of the enzyme rhythm shifted about half a day, and the highest activity was observed around feeding time. However, during the suckling period, no circadian rhythm in the enzyme acvities was found, even when the rats were allowed to feed only during a restricted time of the day.
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PMID:Postnatal development of circadian rhythms in disaccharidase activities in rat small intestine. 41 37

The intestinal brush border disaccharidases separated by gel electrophoresis were studied after oral administration of a high sucrose or lactose diet to 11-day-old suckling rats during 3 days. Some modifications of the brush border protein and eyzyme patterns could be attributed to the effect of the basic diet: increase of glucoamylase, appearance of a weak sucrase activity and of a second molecular form of maltase. However, the specific action of a given disaccharide on the synthesis of the corresponding hydrolytic enzyme could be clearly demonstrated. Indeed, the electrophoretic pattern after sucrose or lactose feeding showed a marked increase of the protein bands corresponding to sucrase-isomaltase or lactase activities.
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PMID:Sucrase and lactase synthesis in suckling rat intestine in response to substrate administration. 41 23

Fifty children consecutively attending a clinic for coeliac disease co-operated in a trial; 10 found to have flat mucosa were excluded. Forty children of mean age 9.8 years, whose duodenal or jejunal mucosa had returned to normal or near normal appearance after a mean of 5.8 years on gluten-free diets, were put back on normal diets. In 37, mucosal occurred in a mean of 16.9 months (four to 74 months). Four of the 37 had serial biopsies, in which mucosal enzymes (particularly lactase) fell and interepithelial lymphocyte counts rose before the mucosal morphology was regarded as definitely 'coeliac'. Three children had normal mucosal appearance after 58 to 73 months on normal diets, one of whom showed temporary mucosal abnormalities, another having occasionally low enzymes, in both suggesting underlying gluten sensitivity. Lactase suppression and raised IEL counts appear to be sensitive indicators of gluten intolerance. In our experience, a diagnosis of coeliac disease based on severe mucosal damage and a satisfactory response to a gluten-free but milk-containing diet implies a very strong likelihood of permanent or prolonged gluten intolerance, but with a striking variability in its expression.
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PMID:Variability of gluten intolerance in treated childhood coeliac disease. 42 24

Fifty hospital patients in Port Moresby (mean age 30 yr) without evidence of malnutrition or gastro-intestinal disease, who came from many parts of Papua New Guinea (P.N.G.), were given 50 g lactose orally after an overnight fast. In 49 blood glucose rise was less than 1.1 mmol 1(-1), indicating hypolactasia. Thirty-three gave a clear history of symptoms, usually diarrhoea, after lactose. Adult hypolactasia approaches 100% in P.N.G. There is no indication that the genetic structure of any part of the population of P,N.G. with regard to lactase has been influenced by genetic drift from peoples with persistence of lactase into adult life (PL).
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PMID:Intestinal lactase status of adults in Papua New Guinea. 43 66


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