Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhibition of microbial enzymes in human dental plaque catalyzing the cleavage of the disaccharides maltose, sucrose and lactose was carried out with the alpha-glucosidase inhibitor, acarbose. The maltases from plaque homogenates were totally inhibited, whereas the inhibition of the invertases varied considerably. With increasing inhibitor concentrations, from 1 mM to 50 mM, the inhibition of the invertases increased. Preincubation for 30 min of the plaque homogenate with inhibitor resulted in a 20% increase of the inhibition of invertase activity. The inhibitor showed non-competitive inhibition of the invertases in the homogenates, whereas the maltases were competitively inhibited. The lactases were not inhibited at all. The invertases from human dental plaque may be alpha-glucosidases and/or beta-fructosidases.
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PMID:Effect of the alpha-glucosidase inhibitor, acarbose, on disaccharide splitting enzymes in human dental plaque. 680 51

There are at least 20 rare autosomal recessive disorders that are excessively common in Finland of which congenital lactase deficiency is one. During the last 17 years we have found 16 cases. In each case the mother noted watery diarrhoea, generally after the first feed of breast milk, and at the latest, by age 10 days. The lactose malabsorption was verified at a mean age of 36 (range 3-90) days, by which time the infants were dehydrated and 15 of them weighed less than at birth (mean weight for age was -2.8 SDs). On a lactose-free elimination diet (a group of 6 on Nutramigen and a group of 10 on soy-based formula) the children caught up in growth. One infant in each group showed allergic symptoms. While the infants were being breast fed their faeces contained 20 to 80 g/l lactose. In 24 peroral lactose tolerance tests, the greatest rise in blood glucose concentration was 0.8 mmol/l. Only 2 patients showed abnormal absorption when tested within a week of lactose elimination, and in each absorption tests became normal during the elimination period. Slight to partial villous atrophy of the jejunum was present in 4 early specimens, but in later ones the mean villous height was normal. The mean height of the epithelial cells was reduced and there were fewer intraepithelial lymphocytes in patients. The lactase activities in jejunal biopsy specimens were lower than in most patients with acquired lactase deficiency, with some overlap. The maltase and sucrase activities were normal.
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PMID:Congenital lactase deficiency. A clinical study on 16 patients. 684 26

Newborn rats born to iron deficient mothers (IDM) were found to have significantly lower hemoglobin, sucrase, lactase and maltase levels compared to control newborn rats. Rats born to IDM and nursed by IDM, when sacrificed at 21 days of age, had statistically significantly lower hemoglobin, serum iron, sucrase, lactase and maltase levels compared to control rats. Rats born to IDM, but nursed by iron sufficient mothers (ISM) and sacrificed at 21 days of age, had hemoglobin, serum iron and sucrase levels compared to control rats whereas lactase and maltase were not corrected by 21 days of nursing by ISM. Rats burn to IDM and nursed by either IDM or ISM for 21 days were given intramuscular iron dextran and placed on iron sufficient diet (ISD) for 7 days. These animals experienced correction of the hemoglobin, serum iron, sucrase and maltase levels compared to control rats, whereas intestinal lactase was not corrected by 7 days of ISD and intramuscular iron. Rats born to ISM, nursed by IDM and sacrificed on day 21 had significantly lower hemoglobin, serum iron and intestinal lactase levels compared to control rats. Rats both to ISM and nursed by IDM were given intramuscular iron dextran on day 21 and placed on an ISD from day 21-28. These animals had a return in hemoglobin, serum iron, sucrase and maltase levels comparable to control rats. Rats born to and nursed by ISM and maintained on an iron deficient diet from day 21-84 had significantly lower hemoglobin, serum iron, sucrase, lactase and maltase levels compared to control rats. Rats born to and nursed by ISM, maintained on iron deficient diet from day 21-84, and then given intramuscular iron dextran on day 84 and maintained on an ISD until day 92, experienced correction of the hemoglobin, serum iron and lactase levels compared to control rats. Intramuscular iron and 7 days of ISD did not correct the sucrase and maltase levels in these rats. Lactose tolerance tests in iron deficient rats showed flat curves compared to controls. After iron treatment, lactose tolerance curves returned to control values. Iron deficiency in rats in utero, during the nursing and postweaning period causes, in addition to anemia, a reduction in jejunal disaccharidase activity because of an alteration in the enzymes of the brush border membrane. Varying degrees of reduction and response of certain disaccharidases to iron treatment are dependent on the time of iron deprivation in relationship to the intra-uterine and postnatal development of the digestive and absorptive functions in the small intestine. Alterations in the levels of disaccharidases demonstrated in this paper represents another aspect of the spectrum of biochemical effects of iron deficiency.
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PMID:Disaccharidase levels in iron deficient rats at birth and during the nursing and postweaning periods: response to iron treatment. 707 2

Ontogenic development continues after birth in mammalian enteric epithelium as an adaptive mechanism to extrauterine life. In the rat, particularly significant developmental changes in enteric structure, function, and cytokinetic properties occur over a short critical period (usually between 16 and 20 days of age), preparatory to dietary change with weaning. Surgical bypass of ileal segments was performed on suckling rats of 12-14 days of age, and the effect on subsequent intestinal development was studied in both the bypassed and the shortened segment remaining in continuity. The bypassed segment, although achieving normal maturational patterns of active sucrase appearance and maltase accumulation, continued to maintain coincident immature patterns of high lactose activity and low cell turnover times. The intestine in continuity showed precocious appearance of active sucrase and accumulation along with maltase to greater than control levels, accompanied by a normal coincident decline in lactase activity and enterocyte life-span. Involvement of intraluminal influences on various parameters of enteric ontogenic development is thus indicated with the effects expressed by a delay in the excluded (bypassed) segment and by stimulation in the shortened segment in continuity. Data are presented in further support of the hypothesis that the life-span of the enterocyte serves postnatally as a primary determinant of enteric lactase levels.
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PMID:Delayed ontogenic development in the bypassed ileum of the infant rat. 722 78

This study was designed to determine the critical difference between rat milk and rat chow with respect ot their effects on jejunal sucrase activity during the fourth postnatal wk. Rats were weaned onto special diets on postnatal day 17, and jejunal sucrase was assayed on day 28. A pelleted diet containing lactose as sole carbohydrate did not cause depression of sucrase activity. Sucrase values (micromoles/hr/mg protein) were 10.49 +/- 0.81 (n = 15) for the lactose chow and 6.65 +/- 0.29 (n = 16) for the sucrose chow. This indicates that the nature of the dietary carbohydrate does not account for the sucrase differences of weaned and nonweaned animals. Likewise, the physical consistency of the diet is unimportant because sucrase values were just as high on liquid diet (10.91 +/- 0.77 micromoles/hr/mg protein; n = 8) as on he solid diets. However, when the relative proportions of carbohydrate and fat in the diet were varied, there were significant effects on sucrase activity; values on a low carbohydrate diet (4.30 +/- 0.33 micromoles/hr/mg protein; n = 8) being less than one-half those on a high carbohydrate diet (10.91 +/- 0.77 micromoles/hr/mg protein; n = 8).
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PMID:Role of diet in the determination of jejunal sucrase activity in the weanling rat. 725 54

An oral sucrose tolerance test was performed in a group of 103 children, aged between 3 months and 15 years because of episodic diarrhea and/or abdominal pains. Sucrose malabsorption defined as an abnormal increase in expired hydrogen, was found in only 3 children who suffered from congenital sucrase-isomaltase deficiency. This 1% incidence of sucrose malabsorption was lower than the incidence of lactose malabsorption found in this group (33%). Mean rise in blood glucose during the sucrose test was higher (3.4 +/- 1.4 vs. 2.4 +/- 1.2 mmol/l, p less than 0.0001) and the occurrence of false flat blood glucose curves was lower (3% vs. 12.8%, p less than 0.05) than during the lactose test. These findings are consistent with the higher sucrase activity in the small bowel mucosa compared to lactase. In contrast to the lactose tolerance test, sucrose tolerance test should not be used as a screening procedure for secondary disaccharidase deficiency in children.
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PMID:Diagnostic value of sucrose tolerance test in children evaluated by breath hydrogen measurement. 736 16

Duodenal mucosa showed normal morphology, interepithelial lymphocytes, alkaline phosphatase, and sucrase in a girl with growth retardation and iron deficiency, but normal absorption of lactose and xylose after two years of abnormal stools. Mucosal lactase was low. Fourteen months later mucosal damage consistent with coeliac disease was evident, and gluten intolerance was subsequently confirmed by gluten challenge. It is probable that, in some children, the mucosal lesion occurs very gradually, so that at an early stage with normal morphology, suppression of lactase activity and possibly interference with iron absorption may be the only abnormalities.
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PMID:Early or pre-coeliac mucosa: development of gluten enteropathy. 746 78

In 10 female patients with carcinoma the effect of a single dose of 5-fluorouracil on morphologic alterations of the small bowel mucosa, intestinal disaccharidase-activities and lactose-tolerance-test was studied pre- and 96 hours posttherapy. After having given a standard dose of 1,25-1,50 gr 5-fluorouracil intravenously ( = 22 mg per kilo body weight) histologic changes of the small bowel mucosa (slight edema and shortening of the villi) were noted only in 4 cases. In the other cases the small intestine showed no morphological alterations of the mucosa. In all patients the lactose-tolerance-test after therapy with 5-fluorouracil was not affected. Following the administration of 5-fluorouracil no reduction of intestinal disaccharidase activities (maltase, saccharase, lactase) was observed. As a consequence of our results we suppose, that a patient given a single dose of 5-fluorouracil intravenously needs no specific diet without milk or milk-products.
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PMID:[Anatomical and functional changes of the human small intestine induced by 5-fluorouracil (author's transl)]. 746 19

A 52-kDa protein, CEL3, has been separated from the culture filtrate of Agaricus bisporus during growth on cellulose. A PCR-derived probe was made, with a degenerate oligodeoxynucleotide derived from the amino acid sequence of a CEL3 CNBr cleavage product and was used to select cel3 cDNA clones from an A. bisporus cDNA library. Two allelic cDNAs were isolated. They showed 98.8% identity of their nucleotide sequences. The deduced amino acid sequence and domain architecture of CEL3 showed a high degree of similarity to those of cellobiohydrolase II of Trichoderma reesei. Functional expression of cel3 cDNA in Saccharomyces cerevisiae was achieved by placing it under the control of a constitutive promoter and fusing it to the yeast invertase signal sequence. Recombinant CEL3 secreted by yeast showed enzymatic activity towards crystalline cellulose. At long reaction times, CEL3 was also able to degrade carboxymethyl cellulose. Northern (RNA) analysis showed that cel3 gene expression was induced by cellulose and repressed by glucose, fructose, 2-deoxyglucose, and lactose. Glycerol, mannitol, sorbitol, and maltose were neutral carbon sources. Nuclear run-on analysis showed that the rate of synthesis of cel3 mRNA in cellulose-grown cultures was 13 times higher than that in glucose-grown cultures. A low basal rate of cel3 mRNA synthesis was observed in the nuclei isolated from glucose-grown mycelia.
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PMID:The cel3 gene of Agaricus bisporus codes for a modular cellulase and is transcriptionally regulated by the carbon source. 808 21

We previously reported that lactose handling was significantly improved during late-phase pregnancy in women with a genetically determined adult-type hypolactasia. However, the adaptive mechanisms underlying the enhanced lactose digestion during pregnancy are not clear. Progesterone therapy has been associated in animals with increased intestinal lactase activity. To investigate the potential role of progesterone and estrogen as modulators of human lactase activity during pregnancy, we employed the human-derived intestinal epithelial Caco-2 cell line. Measurements of lactase and sucrase activities were performed in parallel with DNA content in progesterone- and estrogen-treated cells after 5, 10, and 30 days of confluency. Caco-2 monolayer DNA content was observed to increase with duration of culture to an equivalent extent in both hormone-treated and control cultures. Lactase and sucrase activities were similarly unaltered by incubation with either progesterone or estrogen, at any time point tested. These data demonstrate that gestational hormones do not influence intestinal cell number nor disaccharidase activity in Caco-2 cells, at the doses tested. Although these studies were carried out in a malignant cell line, our data suggest that the improved lactose handling observed during pregnancy is probably related to prolonged intestinal transit.
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PMID:Caco-2 cell disaccharidase activities are unaffected by gestational hormones. 902 32


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