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)

Digestive enzymatic activities (disaccharidases, alkaline phosphatase, peptide hydrolases) have been determined in the mucosa of 14 patients with chronic pancreatitis. All had an abnormal secretin-pancreozymin test. Four patients had insulin-dependent diabetes mellitus, four a pathological glucose tolerance test. Nine patients had steatorrhoea. Maltase, sucrase, and alkaline phosphatase activity was significantly elevated in patients with exocrine pancreatic insufficiency, whereas those of lactase, trehalase, and peptide hydrolase were normal. Patients with steatorrhoea had higher maltase and sucrase activity than those without steatorrhoea, whereas decreased glucose tolerance had no effect on brush border enzymatic activity. It is suggested thatdecreased exocrine rather than decreased endocrine pancreatic function is responsible for the increase in intestinal disaccharidase and alkaline phosphatase activity, possible by the influence of pacreatic enzymes on the turnover of brush border enzymes from the luminal side of the mucosal membranes or by direct hormonal stimulation though cholecystokinin.
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PMID:Influence of exocrine and endocrine pancreatic function on intestinal brush border enaymatic activities. 109 2

About 90% of the protein of hamster intestinal brush borders was solubilised in 0.25% (w/v) sodium dodecyl sulphate without total loss of biological activity. Detergent-polyacrylamide gel electrophoresis of the solubilised proteins separated 10-15 bands and partially resolved maltase, lactase, sucrase-maltase, trehalase and alkaline phosphatase activities. The disaccharidases, which were associated with the higher molecular weight proteins, were preferentially solubilised with 0.1%. (w/v) Triton X-100, butanol or papain, whereas Tris and NaI extracted only the lower molecular weight proteins, possible derived from the core filaments. Electrophoresis of brush border proteins metabolically labelled with [14-C] glucosamine suggested that many of the membrane-bound enzymes are glycoproteins. However, chromatography of a papain digest on Sephadex G-200 showed that the sucrase-maltase complex can be separated nearly free of carbohydrate without total loss of activity. The importance of characterizing membrane proteins solubilised by a number of techniques is discussed.
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PMID:Solubilization of brush borders of hamster small intestine and fractionation of some of the components. 113 70

Feeding sodium deoxycholate orally to rats for four days caused depression of the activity of the small intestinal enzymes lactase, sucrase, maltase, alkaline phosphatase, and N-acetyl-beta-glucosaminidase. The first four are brush border enzymes, the last a lysosomal enzyme. Alkaline phosphatase activity recovered very rapidly and rebounded to above the normal level within 24 hours. The activity of the three disaccharidases returned to normal within seven days while no recovery was observed within 96 hours of the activity of the lysosomal enzyme, N-acetyl-beta-glucosaminidase, after removing the bile salt from the diet.
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PMID:Deoxycholate depresses small-intestinal enzyme activity. 114 Jun 27

1. Intestinal brush border enzymes have heterogeneous rates of turnover, the largest proteins having the fastest turnover. Since the membrane faces the intestinal lumen, the effects of pancreatic factors were examined in mediating this turnover. Surgical subtotal pancreatectomy was used as an experimental model to study the turnover of brush border proteins in the absence of most pancreatic secretions. 2. Subtotal (95%) pancreatectomy of rats was found to cause elevations by about 50% of total activity and specific activities of certain brush border enzymes (maltase, sucrase, lactase), but not of others (alkaline phosphatase, trehalase). Rats were judged to be functionally deficient in pancreatic proteolytic enzymes (a) by demonstration of vitamin B-12 malabsorption, which was corrected by trypsin, and (b) by the finding of only about 20% of proteolytic activity appearing in the lumen after a test meal when compared to control. 3. To measure protein turnover in vivo the method of double labelling was used, where [3H]- and [14C]valine were administered intraduodenally in sequence 10 h apart. With this technique, a high 3H/14C ratio is correlated with rapid turnover. Proteins with apparent molecular weights of about 200 000-270 000 were found to turn over more rapidly than smaller proteins. 3H/14C ranged from 4.7 to 6.2 in animals without pancreatic insufficiency. In the face of decreased pancreatic proteolysis, the 3H/14C ratio was 2.3-3.1, similar to that of proteins with a slow half life. 4. Estimates of relative synthetic rates of large brush border proteins were lower than normal in pancreatectomized animals, but were constant over the period of the labelling experiment. The high enzyme levels in the face of lower synthetic rates confirms that, at the new steady rate, degradation rates must be slower for large brush border proteins in pancreatic insufficiency. 5. In vitro, using purified brush borders, unfractionated pancreatic enzymes were found to remove sucrase, maltase and lactase, but not alkaline phosphatase and trehalase. The enzyme most potent in this respect was the pancreatic protease, elastase. Non-proteolytic enzymes (amylase, lipase, phospholipase A) were inactive in removing enzyme from the brush border. The addition of elastase to pancreatectomized animals in vivo restored the rapid turnover rate of large brush border proteins. 6. A model is thus proposed for the normal catabolism of some large intestinal brush border proteins. It is suggested that the surface of intestinal absorptive cells is being constantly remodelled, and that certain surface enzymes are in part removed from the membrane by the action of pancreatic proteases. A possible special role for elastase is suggested.
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PMID:The possible role of pancreatic proteases in the turnover of intestinal brush border proteins. 114 88

Jejunal biopsies from 19 adult Greenland Eskimos were studied regarding disaccharidases, two intracellular beta-galactosidases, and morphological appearance. Fifteen of the patients (79%) had low lactase activity, and 3 of these (16%) had sucrase-isomaltase deficiency as well. Two patients had low trehalase activity. Microscopical appearance was essentially normal in all the biopsies, except for a certain stromal plasma cell infiltration. All the patients with low lactase activity had a measurable residual activity of brush border lactase, which was localized in the middle and apical parts of villi, as normally seen for digestive enzymes. Lysosomal acid beta-galactosidase and cytosol hetero beta-galactosidase were not altered. In the patients with sucrase-isomaltase deficiency there was a complete absence of active sucrase-isomaltase complex. The residual maltase, as well as the very weak residual isomaltase, was exerted exclusively by the heat stable maltases (maltase II and III). The material is the first one in which multiple, but not generalized disaccharidase deficiencies are demonstrated.
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PMID:Intestinal disaccharidases in Greenland Eskimos. 115 47

Studies have been done on the effect of Penicillin, Streptomycin and Isonicotinic Acid hydrazide on small intestinal oligosaccharidase and it was observed that the drug penicillin inhibited the enzyme lactase and sucrase by 62.7% and 34.7% respectively, whereas I.N.H. inhibited the enzyme sucrase and maltase by 57.1% and 56.14% respectively. Streptomycin did not show any inhibitory effect on those enzymes. Lactose tolerance test showed impairment of lactose absorption in case of penicillin. Fasting serum sugar level was diminished both in penicillin and streptomycin and the absorption capacity was increased after oral administration of streptomycin.
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PMID:Studies on the effect of penicillin, streptomycin and isonicotinic acid hydrazide on small intestinal oligosaccharidase. 115 32

The acute effects of intraduodenal administration of ethanol, 5 g/kg body weight, on intestinal activities of lipid-reesterifying and disaccharidase enzymes of the small bowel were studied. Results were compared to those produced in controls receiving isocaloric amounts of glucose by the same route. Acyl-CoA:monoglyceride acyltransferase, acyl-CoA synthetase (acid:CoA ligase (AMP) EC 6.2.1.3), sucrase, and lactase assays were performed on jejunal samples; acyl-CoA synthetase assay was performed on ileal samples. Ethanol produced greater activities of the lipid-reesterifying enzymes in the jejunum than did glucose. Ileal specific activity of acyl-CoA synthetase was also increased in the experimental group. No effect of ethanol on jejunal disaccharidase enzyme activities was noted. It is concluded that ethanol given acutely has a specific stimulating effect on intestinal enzymes involved in lipid absorption.
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PMID:The effect of acute ethanol treatment on lipid-reesterifying enzymes of the rat small bowel. 116 87

Small intestinal lactase activity in the health adult is either the same as in early infancy or may drop to very low levels. The behavior of the enzymatic state varies with the ethnic group studied. In those adults with low lactase activity little information is availalbe as to the age at which the lactase decreases. We attempted to determine a) the frequency of low intestinal lactase activity and b) the age at which the change occurs. For this purpose we reviewed in a large number of intestinal biopsies both histologically as well as for disaccharidase activities. The biopsies were obtained from a heterogeneous group of Caucasians, including patients, their siblings and parents. The patients were those with failure to thrive in whom no organic cause could be elicited, and those with the irritable colon syndrome. Patients ranged in age from 6 weeks to 50 years and out of a total of 1, 077 jejunal biopsies, 172 morphologically normal biopsies were selected. The milk drinking habits of 118 subjects and their families were elicited and 31 oral lactose tolerance tests performed. The mucosal lactase activity and sucrase-to-lactase ratio in those 172 individuals were plotted against age. In the first 3 years the mean lactase activity was 32.1 plus or minus 10.1 mumoles/g protein per min and the sucrase-to-lactase ratio was 1.7 plus or minus 0.5 with no change from year to year. However, after age 5 two separate groups emerge. A small group (24.6% of the population) with low lactase activity, and a second group possessing the same mean value for lactase activity as noted in the first 3 years. The low lactase activity group included children and adults with clinical lactose intolerance. These individuals consumed relatively small amounts of milk and when 12 of them were tested with an oral lactose tolerance test the result was a "flat" curve with a maximum rise in blood glucose of 9 plus or minus 3.2 mg/100 ml. The second group consumed more milk averaging 1 quart/day with no discomfort and when 19 were tested with oral lactose tolerance tests the values were normal. This study indicates that low lactase activity in the Caucasian population may make its appearance at the age of 5 years.
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PMID:Correlation of lactase activity, lactose tolerance and milk consumption in different age groups. 117 20

Maltase, sucrase, and lactase were measured at pH 4 and pH 6 in normal and intestinalized gastric mucosa. In the normal mucosa the low activities of maltase and lactase seemed to be entirely due to lysosomal enzymes with acid pH-optimum. In intestinal metaplasia, brush border maltase and sucrase, but not lactase, appeared. On the other hand, there was a significant increase in lysosomal lactase (beta-galactosidase) activity.
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PMID:Disaccharidase activities in intestinal metaplasia - contribution of lysosomal brush border enzymes. 117 60

Meconium ileus represents the earliest clinical manifestation of cystic fibrosis. The differences found in the composition and amount of protein, mucoprotein, mucopolysaccharides, and reducing sugars in meconium from newborns with cystic fibrosis might be of significance relative to the pathogenesis and early diagnosis of this disease. We studied the enzymatic activity of disaccharidases (lactase, sucrase, maltase, and palatinase) in meconium of infants with cystic fibrosis and controls. We found an increase in the specific activity of these enzymes in the meconium from infants with cystic fibrosis as compared to the specific activity in meconium from normal infants. The increase in the activities, expressed as micromols per gram of protein per minute was: lactase, 100 times higher; sucrase, 18 times; maltase, 4.8 times, and palatinase, 8.9 times.
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PMID:Studies in meconium: disaccharidase activities in meconium from cystic fibrosis patients and controls. 119 37


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