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)

Intestinal mucosa and pancreas from purebred Beagle dogs were assayed for carbohydrase activity, using several methods of tissue treatment. The enzymes found and studied were alpha-amylase, sucrase, lactase, amyloglucosidase, cellobiase, maltase, and isomaltase. Experiments using polyacrylamide gel columns and heat inactivation showed the presence of an isozyme of maltase which degrades isomaltose. This activity had not been previously demonstrated in dogs. An optimal standard procedure is presented for the preparation and assay of canine digestive enzymes. A statistical analysis of variance of the results showed that the variance was primarily associated with differences among dogs and not by variance within the procedure. When the different extraction procedures were used, results indicated that the level of enzymes detected differed with the method of treatment.
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PMID:Detection and definition of canine intestinal carbohydrases, using a standardized method. 88 14

Twenty (12 Holstein, 8 Longhorn cross) calves (198 kg and 7 mo old) were used in a randomized complete block design to evaluate the effects of dietary forage concentration and feed intake on carbohydrase activities and small intestinal (SI) morphology. Calves were individually fed 90% forage (alfalfa) or a 90% concentrate (50% sorghum: 50% wheat) diet at either one or two times NEm for 140 d and slaughtered; tissues and small intestinal digesta were collected. Increased feed intake increased (P less than .05) pancreatic weight, alpha-amylase and glucoamylase activities in the pancreas, SI length and SI digesta weight. Forage-fed calves gained faster (P less than .01) and had greater (P less than .05) pancreatic protein concentrations, alpha-amylase and glucoamylase activities in the pancreas and greater SI digesta alpha-amylase activities than grain-fed calves did. Increased feed intake increased (P less than .01) mucosal weight/cm small intestine only in forage-fed calves and increased (P less than .05) SI surface/volume only in grain-fed calves. Mucosal weight was greatest (P less than .05) at the terminal ileum, surface/volume was greatest (P less than .05) in the duodenum, and mucosal protein concentration was highest (P less than .05) in the SI mid-section. Mucosal lactase was higher (P less than .05) in proximal segments, whereas mucosal isomaltase was higher in middle and distal segments of the small intestine. For mucosal maltase activity, there was a feed intake x SI sampling site interaction (P less than .05) and for trehalase, a diet x feed intake x SI sampling site interaction (P less than .05). The SI distribution patterns of maltase and isomaltase were similar, as were those of trehalase and lactase. The alpha-amylase activity in the pancreas and SI morphology were influenced greatly by diet composition and feed intake by calves.
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PMID:Influence of dietary forage and feed intake on carbohydrase activities and small intestinal morphology of calves. 169 58

1. One litter of 12 pigs was used to evaluate the effects of hydrocortisone acetate injection on organ weight and carbohydrase activities. 2. Pigs were injected with hydrocortisone acetate or an equal volume of saline at 7 days of age and killed at 14 days, and tissues were collected, weighted, and analyzed for carbohydrase activities. 3. Hydrocortisone had no effect (P greater than 0.40) on daily gain, liver weight, spleen weight, or small intestinal length. 4. Hydrocortisone increased pancreatic weight by 29% and total pancreatic alpha-amylase content by 38%. 5. Hydrocortisone increased duodenal mucosal weight by 23%, duodenal lactase activity by 44%, duodenal maltase activity by 163%, and duodenal sucrase activity by 214%.
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PMID:Influence of hydrocortisone acetate on pancreas and mucosal weight, amylase and disaccharidase activities in 14-day-old pigs. 170 74

Three carbohydrate analyses (reducing value by copper-bicinchoninate, total carbohydrate by phenol-sulfuric acid, and D-glucose by glucose oxidase) have been miniaturized using a microsample plate reader. The use of the reducing-value procedure to measure the hydrolysis of starch by alpha-amylase and the use of the glucose oxidase method to measure the hydrolysis of lactose by lactase are illustrated.
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PMID:Miniaturization of three carbohydrate analyses using a microsample plate reader. 188 21

The influence of hydrolysis on the assimilation rate of important nutritional carbohydrates was studied in healthy subjects and patients with intestinal diseases, mainly by means of 13CO2 breath test techniques. All substrates were "naturally enriched" with carbon-13. The studies showed that hydrolysis is the rate limiting step for the assimilation of lactose, starch and even maltose, but not for the assimilation of sucrose. The degree of gelatinisation and the degree of side-branching of starch molecules were two important parameters, influencing starch hydrolysis in normal subjects. Addition of wheat bran had no influence on the digestion rate of starch. A comparative study between normal subjects and patients with pancreatic disease, showed that starch digestion may be impaired in patients with pancreatic disease. However, this occurs only if amylase output is extremely low. The effect of lactase deficiency on lactose absorption was studied in patients with a history suggestive of lactase deficiency. For this purpose a lactose 13CO2 and H2 breath test were compared with lactase activity in a jejunal biopsy. The results showed that the relation between lactase activity in the biopsy and lactose assimilation takes the form of a saturation curve. The 13CO2 breath test was found to be a reliable test for the diagnosis of lactase deficiency. Finally, the effect of acarbose on starch digestion was studied in normal subjects, ileostomy patients, and a fecal incubation system. These experiments showed that acarbose may induce an important degree of starch malabsorption. If administered in high doses, the effect is not only related to inhibition of brush border enzymes, but also to the inhibition of alpha-amylase.
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PMID:Georges Brohee Prize 1988-1989. Assimilation of nutritional carbohydrates: influence of hydrolysis. 205 48

Three pseudo-aminosugars, validamine, valienamine and valiolamine, produced by Streptomyces hygroscopicus subsp. limoneus showed potent inhibitory action on rat small intestinal carbohydrase activities such as sucrase, maltase, glucoamylase, isomaltase and trehalase activities, but negligible action on lactase activity and pancreatic alpha-amylase activity. Where inhibition was seen, kinetic analysis showed fully competitive inhibition of the carbohydrase activities by all three inhibitors. Valiolamine has more potent carbohydrase inhibitory activity than validamine or valienamine, and the apparent Ki values of valiolamine for sucrase, maltase, glucoamylase, isomaltase and trehalase activities were 3.2 x 10(-7), 2.9 x 10(-6), 1.2 x 10(-6), 9.1 x 10(-7) and 4.9 x 10(-5) M, respectively, which are 10(-5) to 10(-3) times smaller than the apparent Km values.
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PMID:Inhibitory effect of validamine, valienamine and valiolamine on activities of carbohydrases in rat small intestinal brush border membranes. 226 98

Sprague-Dawley rats fed a nonpurified diet from weaning to 3 mo (young) or 12 mo (middle aged) of age were fed a low (5 cal%) starch (LST) purified diet for 2 wk. They were then fed a high (70 cal%) starch (HST) purified diet for up to 4 wk. Body weights of both age groups were greater in rats fed the LST than in those fed nonpurified diet throughout. The young, but not the middle-aged, group continued this gain while consuming HST. The levels of activity of intestinal disaccharidases of upper (proximal one-third) and lower (middle one-third) jejunum, and pancreatic alpha-amylase were lower in rats fed LST diet in both age groups than in rats fed HST. Similar increases of specific (per protein or DNA) activity were observed in both age groups throughout the first three (disaccharidase) to four (pancreatic alpha-amylase) days of feeding HST. Values of specific activity of the middle-aged group returned to initial levels with continued feeding of HST. In contrast, values in the young group tended to plateau (disaccharidases) or continued to increase (alpha-amylase). Differences in adaptability over 1 mo were most dramatic for alpha-amylase and sucrase, but negligible for lactase.
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PMID:Response of activity of jejunal disaccharidases and pancreatic amylase in young and middle-aged rats to a high carbohydrate diet. 243 33

Dietary fibres (Plantago ovata seeds, P. ovata husks, wheat bran, alfalfa, pectin, xylan) were incubated in vitro with gastrointestinal enzymes (pepsin, trypsin, chymotrypsin, lipase, alpha-amylase, maltase, lactase) in buffer solutions at concentrations of 1-5% for 10-30 min at 37 degrees C. All fibres induced sometimes pronounced changes in enzyme activity, but the effect of the different fibres on the various enzymes varied individually and was not predictable. Both P. ovata preparations had no (pepsin, trypsin, alpha-amylase) or only stimulating (chymotrypsin, lipase, lactase) actions whereas all other fibres showed inhibiting as well as stimulating influences. Wheat bran induced the most pronounced alterations increasing lipase, maltase and lactase activity and inhibiting alpha-amylase activity. Pectin and xylan were comparable in decreasing lipase and pepsin activity and in increasing chymotrypsin activity but had opposite effects on maltase activity. Alfalfa was able to stimulate lactase and lipase activity but depressed trypsin and alpha-amylase activity. The inactivation of enzymes by dietary fibres can, at least partly, be explained by adsorption to the fibre or by the presence of enzyme inhibitors especially in natural compounds. The reasons for activation processes are unknown. As enzyme activities are decisive for food digestion, the properties of the individual fibres should be carefully considered when used as dietary supplement in physiological or pathological conditions.
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PMID:Interference of dietary fibres with gastrointestinal enzymes in vitro. 248 92

The treatment of lactating mothers with 50 micrograms/100 g b.w. thyroxine s.c. daily from the 1st to 21st day of lactation resulted in earlier induction of alpha-glucosidases (pancreatic alpha-amylase, intestinal saccharase) and in earlier repression of beta-galactosidases (intestinal lactase). In contrast, the sucklings fed by thyroidectomized mothers showed a delayed induction of pancreatic alpha-amylolytic activity and intestinal saccharase, but ameliorated the repression of lactase. The treatment of another group of thyroidectomized mothers with 5 micrograms/100 g b.w. thyroxine prevented such effects mothers of thyroidectomy in sucklings.
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PMID:Postnatal development of pancreatic alpha-amylase and intestinal saccharase and lactase in rat sucklings as related to thyroid function of mothers. 250 96

By means of biochemical determination of the activity of hydrolases in the digestive system, studies have been made on the enzymic spectrum in the pancreas and small intestine in postnatal life of astrakhan sheep. It was shown that to the moment of birth, animals possess the developed mechanisms of the initial and final stages of hydrolysis of proteins and lipids. At this period, carbohydrate hydrolysis system is presented only by lactase, the activity of pancreatic alpha-amylase, intestinal gamma-amylase and maltase being very low, whereas the activity of saccharides is absent at all. During further development of sheep, the activity of all digestive hydrolases gradually increases, except that of lactase which is almost absent in adult specimens. Saccharides activity was not find in the mucose of the small intestine within the whole postnatal life.
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PMID:[The enzyme systems of the cavitary and membrane hydrolysis of foodstuffs in the ontogeny of Karakul sheep]. 259 5


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