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)

1. The disaccharidases, cellobiase, isomaltase, lactase, maltase, sucrase and trehalase were investigated for presence in the camel (Camelus dromedarius) intestine and pancreas. All, except sucrase, were present. 2. Their levels of activities were measured at different positions of the small and large intestines and the location of maximum level of activity for each enzymes along the intestinal tract was established. 3. High levels of activities were determined in the contents of the intestinal lumen and, therefore, it is absorbed into the cells of the epithelial villi and hydrolyzed there. 4. The possibility of carbohydrate digestion in camel intestine is discussed.
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PMID:The level and distribution of disaccharidases in the camel (Camelus dromedarius) intestine. 612 46

The influence of hydrocortisone (10(-8)--10(-5) M) and thyroxine (10 (-9)--10(-6) M) on intestinal epithelial cell differentiation and proliferation have been studied using explants of suckling mouse jejunum maintained in serum-free organ culture. Hydrocortisone induced the appearance of sucrase activity and increased trehalase, glucoamylase, lactase and alkaline phosphatase activities. Thyroxine was completely ineffective at all the concentrations used. None of these hormones affected the mitotic activity or the 3H-thymidine incorporation into DNA. These results demonstrate that hydrocortisone but not thyroxine acts directly on intestinal brush border membrane differentiation and that both hormones do not influence the proliferation of the epithelial cells during postnatal development.
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PMID:Comparative study of the effect of hydrocortisone and thyroxine on suckling mouse small intestine in organ culture. 614 44

Explants of suckling mouse jejunum have been maintained in serum-free organ culture with or without insulin added to the medium in order to determine the possible direct effect of this hormone on the hydrolytic functions of the brush border and on the proliferation of the crypt cells. The addition of insulin induced the precocious appearance of sucrase activity and increased trehalase, glucoamylase and lactase activities. Alkaline phosphatase activity remained unaffected in the tissue as well as in the medium. An increased DNA content and 3H-thymidine incorporation into DNA were already recorded after 24 h of culture. The mitotic index was significantly increased after 24 h and remained elevated when the culture was extended to 48 h. These results show that insulin directly influences the enzymatic maturation and the proliferation of intestinal epithelial cells of suckling mouse.
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PMID:Insulin influences the maturation and proliferation of suckling mouse intestinal mucosa in serum-free organ culture. 639 67

In 35 infants trehalose-load-tests were carried out, biopsies of the intestinal mucosa of each patient were taken, and examined histologically. Furthermore, the enzyme activities of trehalase and lactase in each biopsy were determined. It was possible to demonstrate that morphology and function of the intestinal mucosa correlate differently depending on the severity of the mucosal damage. If there is only moderate mucosal damage, a rather weak correlation is seen either for the trehalose-load-test or for the disaccharidase activities with morphological changes. If damage was absent or severe, correlation improved. Both methods in comparison show a better correlation between trehalase activity and morphology than between trehalose-load-test and morphology. Furthermore, trehalase activity corroborated the histological findings better than lactase activity.
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PMID:[Trehalose-load test in gastroenterology]. 640 31

The development of small intestinal enzymes (lactase, acid- and hetero beta-galactosidases, cellobiase, maltase, trehalase, and sucrase) was studied from 18 days after conception until birth in 24 rabbit fetuses, and during the postnatal period in 15 newborn, juvenile, and adult rabbits. Lactase, acid- and hetero beta-galactosidases, cellobiase, and trehalase activities increased significantly during the fetal stage, while changes in sucrase and maltase activities were not substantial. In the postnatal period, lactase and cellobiase activities decreased significantly whereas maltase, sucrase, and trehalase activities increased significantly to reach adult values by 30 days of age. The acid- and hetero beta-galactosidases remained unchanged.
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PMID:The fetal and postnatal development of small intestinal disaccharidases in the rabbit. 643 Nov 90

Intestinal disaccharide uptake was studied with isolated brush-border membrane vesicles lacking the corresponding hydrolase. Either 15-day-old chick intestine, lacking both trehalase and lactase, or newborn pig intestine, lacking sucrase, was used. Both animal species yielded osmotically active vesicles capable of D-glucose/Na+ cotransport with a positive overshoot test. Vesicles from either origin gave quantitatively similar results in regard to both initial uptake rates and relative vesicle volumes. The nontransported analogs D-mannitol and L-glucose were used as diffusion markers. When tested with the appropriate disaccharidase-lacking vesicles, lactose, trehalose and sucrose exhibited uptake rates indistinguishable from those of D-mannitol and L-glucose. These uptakes were unaffected by the presence or absence of Na+, phlorizin and Tris. Chromatographic analysis confirmed the lack of hydrolysis of each disaccharide after prolonged incubation. The inescapable conclusion seems to be that intact disaccharides are not transported through the brush-border membrane, their uptake occurring through simple diffusion.
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PMID:Disaccharide uptake by brush-border membrane vesicles lacking the corresponding hydrolases. 643 45

Comparison of relative disaccharidase activities in jejunal mucosa, amniotic fluid, and meconium samples taken from the ileum, proximal and distal colon of 5 human fetuses, indicates that trehalase and lactase are more sensitive to the denaturation conditions existing in the fetal intestinal lumen than maltase, sucrase, palatinase and turanase . Relative activities of sensitive disaccharidases (trehalase and lactase) were also low in the amniotic fluid of these fetuses as compared to the jejunal mucosa. These results suggest that the in vivo stability of disaccharidases, exposed to proteolytic digestion and other denaturing conditions in the fetal intestinal lumen, governs the relative activities of these enzymes released into the amniotic fluid.
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PMID:Differential stabilities of fetal intestinal disaccharidases determine their relative amounts released into amniotic fluid. 672 23

Rats were made severely uremic with partial nephrectomy (24-hour creatinine clearance 10% of normal). Jejunal dipeptidase activities (substrates: glycyl-L-leucine, L-alanyl-L-proline, and L-methionyl-L-methionine), disaccharidase activities (maltase, sucrase, trehalase, and lactase) and morphology were studied. A highly significant increase in glycyl-L-leucine and L-methionyl-L-methionine dipeptidases was found in uremic rats compared with controls. Proline dipeptidase activities were unaltered. Disaccharidase activities showed a slight increase in sucrase in uremic rats; otherwise no change was found.
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PMID:Small intestinal dipeptidases and disaccharidases in experimental uremia in rats. 677 73

Protein turnover in brush-border membranes of rats during postnatal development has been studied by the double isotope technique. Unlike adult animals where only large proteins (mol wt > 140,000) show relatively rapid turnover, most brush-border proteins in 12-day-old rats show high 3H-to-14C ratios of leucine incorporation, consistent with rapid turnover. Lysosomal proteases, including cathepsin B, are partly responsible for this rapid turnover. This conclusion is based on the following findings: 1) In vivo treatment of 12-day-old animals with leupeptin, an inhibitor of cathepsin B, alters relative turnover rates, enzyme activity, and content of many brush-border proteins. Activities of maltase and trehalase rise while lactase falls. 2) Cathepsin B activity falls rapidly in intestine after the animals are 16 days of age, at a time when luminal pancreatic proteases are rising. Moreover, cathepsin B activity shows less latency in distal intestine at 12 and 16 days than at later ages or in proximal intestine. It is suggested that during postnatal development lysosomal enzymes, e.g., cathepsin B, play an important role in the turnover of intestinal brush-border proteins.
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PMID:Turnover of intestinal brush-border proteins during postnatal development in rat. 677 25

The activities of various glycosidases in homogenates of the small intestinal mucosa of two adult and 18 suckling tammar wallabies (M. eugenii) aged from 6 to 50 weeks were investigated. Lactase (beta-D-galactosidase), beta-N-acetylglucosaminidase, alpha-L-fucosidase and neuraminidase activities were high during the first 34 weeks post partum and then declined to very low levels. Maltase, isomaltase, sucrase and trehalase activities were very low or absent during the first 34 weeks, and then increased. The lactase activity was unusual in being greater in the distal than the middle or proximal thirds of the intestine, and in its low pH optimum (pH 4.6), inhibition by p-chloromercuribenzene sulfonate but not by Tris, and lack of cellobiase activity. These properties are those of a lysosomal acid beta-galactosidase rather than of a brush border neutral lactase. The maltase activity had the characteristics of a lysosomal acid alpha-glucosidase early in lactation and of a brush border neutral maltase in adult animals. The significance of these findings is discussed in relation to changes in dietary carbohydrates during weaning and to the mode of digestion of milk carbohydrates by the pouch young.
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PMID:Intestinal lactase (beta-galactosidase) and other glycosidase activities in suckling and adult tammar wallabies (Macropus eugenii). 678 21


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