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

We studied the ontogeny of the intestinal brush border disaccharidases sucrase and lactase in the precocial rodent Octodon degus. Sucrase hydrolyze sugars from plants while lactase hydrolyzes sugars from milk. Enzyme expression varied inversely with dietary changes according to the developmental pattern. All new-born pups had high lactase and low sucrase activities. Also, a negative correlation between sucrase and lactase activity was found, supporting the economic design hypothesis for the intestinal tract. Profiles for development of sucrase expression exhibit some differences among precocial species, and in O. degus is correlated with the slower transition from milk to solid food consumption at weaning.
Comp Biochem Physiol A Mol Integr Physiol 2003 Feb
PMID:Ontogenic development of intestinal disaccharidases in the precocial rodent Octodon degus (Octodontidae). 1254 69

Lactase persistence is a heritable, autosomal dominant, condition that results in a sustained ability to digest the milk sugar lactose throughout adulthood. The majority of the world's human population experiences a decline in production of the digestive enzyme lactase-phlorizin hydrolase during maturation. However, individuals with lactase persistence continue to express high levels of the lactase gene into adulthood. Lactase persistence has been strongly correlated with single nucleotide genetic variants, C/T_(13910) and G/A_(22018), located 13.9 and 22 kb upstream from the lactase structural gene. We aimed to characterize a functional role for the polymorphisms in regulating lactase gene transcription. DNA in the region of the C/T_(13910) or G/A_(22018) human lactase variants was cloned upstream of the 3.0 kb rat lactase gene promoter in a luciferase reporter construct. Human intestinal Caco-2 cells were transfected with the lactase variant/promoter-reporter constructs and assayed for promoter activity. A 200 bp region surrounding the C_(13910) variant, associated with lactase non-persistence, results in a 2.2-fold increase in lactase promoter activity. The T_(13910) variant, associated with lactase persistence, results in an even greater 2.8-fold increase. The DNA sequence of the C/T_(13910) variants differentially interacts with intestinal cell nuclear proteins on EMSAs. AP2 co-transfection results in a similar repression of the C/T_(13910) variant/promoter-reporter constructs. The DNA region of the C/T_(13910) lactase persistence/non-persistence variant functions in vitro as a cis element capable of enhancing differential transcriptional activation of the lactase promoter. Such differential regulation by the C and T variants is consistent with a causative role in the mechanism specifying the lactase persistence/non-persistence phenotypes in humans.
Hum Mol Genet 2003 Sep 15
PMID:Lactase persistence DNA variant enhances lactase promoter activity in vitro: functional role as a cis regulatory element. 1291 62

The present study analyzed the existence of carbohydrases in camel pancreas compared to some other ruminants. Disaccharidases (maltase, cellobiase, lactase, trehalase and sucrase), glucoamylase and alpha-amylase were detected in pancreas of camel, sheep, cow and buffalo. Enzyme levels in sheep were lower than in the other ruminants. The highest level was detected for alpha-amylase (EC 3.2.1.2). Moderate activity levels were detected for glucoamylase (EC 3.2.1.3) and maltase (EC 3.2.1.20), while other disaccharidases showed very low activity. The results suggested that, in addition to alpha-amylase, glucoamylase and maltase may be synthesized and secreted from pancreas to the small intestine in ruminants. Camel pancreatic glucoamylase was purified and characterized. The purification procedure included glycogen precipitation and chromatography on DEAE-Sepharose and Sepharose 6B. The molecular mass was 58 kDa for native and denatured enzyme using gel filtration and SDS-PAGE, respectively. The enzyme had a pH optimum at 5.5 and a Km of 10 mg starch/mL with more affinity toward potato soluble starch than the other carbohydrates. Glucoamylase had a temperature optimum at 50 degrees C with heat stability up to 30 degrees C. The effect of different cations and inhibitors was examined. The camel pancreatic glucoamylase may possess an essential thiol.
Comp Biochem Physiol B Biochem Mol Biol 2005 Jan
PMID:Carbohydrases in camel (Camelus dromedarius) pancreas. Purification and characterization of glucoamylase. 1562 12

Specific activities of both intestinal and renal dissacharidases, such as sucrase, maltase, and lactase, were altered in diabetic rats. Our study was focused to evaluate the effect of feeding quercetin - a bioflavanoid on intestinal and renal dissacharidases in streptozotocin-induced diabetic rats. The rats were fed with 0.1% quercetin in diet. A reduction in intestinal maltase and sucrase, activities in quercetin-fed diabetic rats was observed in contrast to the increased activities in the starch-fed diabetic rats. A significant amelioration in renal dissacharidase activities in quercetin-fed diabetic rats was observed when compared to decreased activity in starch-fed diabetic rats.
Mol Nutr Food Res 2005 Apr
PMID:Quercetin alleviates activities of intestinal and renal disaccharidases in streptozotocin-induced diabetic rats. 1574 16

During diabetes, structural and functional changes in the alimentary tract are known to take place resulting in increased absorption of intestinal glucose and alterations in the activities of brush border disaccharidases. Similar observations are also reported in the renal cortex. In the present investigation, we examined the effect of feeding bitter gourd fruit devoid of seeds on activities of intestinal and renal disaccharidases, viz., maltase, sucrase, and lactase in streptozotocin-induced diabetic rats. Normal and diabetic rats were fed either with basal diet or a diet containing 10% bitter gourd powder. Specific activities of intestinal disaccharidases were significantly increased during diabetes, and supplementing bitter gourd in the diet clearly indicated amelioration in the activities of maltase and lactase during diabetes. However, a significant change was not observed with sucrase activity by feeding of bitter gourd. During diabetes, renal disaccharidase activities were significantly lower than those in the control rats. Bitter gourd supplementation was beneficial in alleviating the reduction in maltase activity during diabetes. However, not much change in the activities of sucrase and lactase was observed upon feeding. This positive influence of feeding bitter gourd on intestinal and renal disaccharidases clearly indicates their beneficial role in the management of diabetes, thus making diabetic animals more tolerant to hyperglycemia.
Mol Nutr Food Res 2005 Aug
PMID:Bitter gourd (Momordica charantia) modulates activities of intestinal and renal disaccharidases in streptozotocin-induced diabetic rats. 1600 24

Fasting and refeeding effects on gastrointestinal morphology and digestive enzyme activities of Atlantic salmon, held in tanks of seawater at 9 degrees C and 31 per thousand salinity, were addressed in two trials. Trial 1: Fish (mean body mass 1190 g) were fasted for 40 days and intestines sampled at day 0, 2, 4, 11, 19 and 40. Trial 2: Fish (1334 g), fasted for 50 days, were refed and sampled at day 0, 3 and 7. Mass, length, protein, and maltase, lactase, and leucine aminopeptidase (LAP) activities were analyzed for stomach (ST), pyloric caeca (PC), proximal (PI), mid (MI), and distal intestine (DI). PC contributed 50% of gastrointestinal mass and 75% of enzyme capacity. Fasting decreased mass and enzyme capacities by 20-50% within two days, and 40-75% after 40 days. In PC, specific brush border membrane (BBM) maltase activity decreased whereas BBM LAP increased during fasting. Upon refeeding, enzyme capacities were mostly regenerated after one week. The results suggest that refeeding should start slowly with about 25% of estimated feed requirement during the first 3 days, but may then be stepped up rapidly. Investigations of digestive processes of fed fish should only be performed when intestines are feed-filled to avoid bias due to effects of fasting.
Comp Biochem Physiol A Mol Integr Physiol 2005 Aug
PMID:Fasting and refeeding cause rapid changes in intestinal tissue mass and digestive enzyme capacities of Atlantic salmon (Salmo salar L.). 1604 60

Two phenotypes exist in the human population with regard to expression of lactase in adults. Lactase non-persistence (adult-type hypolactasia and lactose intolerance) is characterized by a decline in the expression of lactase-phlorizin hydrolase (LPH) after weaning. In contrast, lactase-persistent individuals have a high LPH throughout their lifespan. Lactase persistence and non-persistence are associated with a T/C polymorphism at position -13,910 upstream the lactase gene. A nuclear factor binds more strongly to the T-13,910 variant associated with lactase persistence than the C-13,910 variant associated with lactase non-persistence. Oct-1 and glyceraldehyde-3-phosphate dehydrogenase were co-purified by DNA affinity purification using the sequence of the T-13,910 variant. Supershift analyses show that Oct-1 binds directly to the T-13,910 variant, and we suggest that GAPDH is co-purified due to interactions with Oct-1. Expression of Oct-1 stimulates reporter gene expression from the T and the C-13,910 variant/LPH promoter constructs only when it is co-expressed with HNF1alpha. Binding sites for other intestinal transcription factors (GATA-6, HNF4alpha, Fox and Cdx-2) were identified in the region of the -13,910 T/C polymorphism. Three of these sites are required for the enhancer activity of the -13,910 region. The data suggest that the binding of Oct-1 to the T-13,910 variant directs increased lactase promoter activity and this might provide an explanation for the lactase persistence phenotype in the human population.
Hum Mol Genet 2005 Dec 15
PMID:T-13910 DNA variant associated with lactase persistence interacts with Oct-1 and stimulates lactase promoter activity in vitro. 1630 Dec 15

The activities of lactase, sucrase and alkaline phosphatase (AP) were studied in intestinal brush border membranes of control and toxin-treated rabbits. Purified Shiga toxin (Stx) exposure to ileal mucosa inhibited activities of brush border enzymes by 50%. Kinetic analysis revealed that the observed decrease in BBM enzyme activities was due to reduced V(max) with no change in the affinity constants of the systems. The observed changes in enzyme activities were corroborated by Western Blot analysis of lactase, sucrase and AP. The mRNA levels encoding sucrase and lactase proteins in control and Shiga toxin-treated rabbit ileum did not show any change in the rabbit ileum. Histopathological analysis showed short, blunt villi with increased number of inflammatory cells in the lamina propria and extrusion of cells in to the lumen of Stx-treated rabbit ileum. The present findings suggest that Shiga toxin act by inhibiting protein synthesis of these brush border functional proteins beyond their transcriptional level and by the direct damage to intestinal epithelium, which could be implicated in the pathogenesis of diarrhea.
Mol Cell Biochem 2006 Feb
PMID:Shiga toxin exposure modulates intestinal brush border membrane functional proteins in rabbit ileum. 1644 89

The present study was designed to evaluate the influence of two commonly prescribed non-steroidal anti-inflammatory drugs (NSAIDs), aspirin and nimesulide on the biochemical composition and membrane dynamics of rat intestine. Female Wistar rats were divided into three different groups viz: Group I (Control), Group II (aspirin-treated, 50 mg/kg body weight) and Group III (nimesulide-treated, 10 mg/kg body weight). After 28 days, biochemical estimations in both drug treated groups showed an increase in sucrase, lactase, maltase and alkaline phosphatase as compared to the control. Alterations in the intestinal membrane dynamics by fluidity studies and Fourier Transform Infra Red (FTIR) spectroscopy also showed considerable changes. The alterations in the histoarchitecture of the intestine were also seen, which correlated well with the changes in structure and composition of the intestine. The use of NSAIDs like aspirin and nimesulide may cause the gastrointestinal side effects due to initial changes in the enzyme activities and membrane dynamics.
Mol Cell Biochem 2007 Jan
PMID:Modulations in the intestinal disaccharide hydrolases and membrane dynamics: effect of non-steroidal anti-inflammatory drugs aspirin and nimesulide. 1685 94

Gata4, a member of the zinc finger family of GATA transcription factors, is highly expressed in duodenum and jejunum but is nearly undetectable in distal ileum of adult mice. We show here that the caudal reduction of Gata4 is conserved in humans. To test the hypothesis that the regional expression of Gata4 is critical for the maintenance of jejunal-ileal homeostasis in the adult small intestine in vivo, we established an inducible, intestine-specific model that results in the synthesis of a transcriptionally inactive Gata4 mutant. Synthesis of mutant Gata4 in jejuna of 6- to 8-week-old mice resulted in an attenuation of absorptive enterocyte genes normally expressed in jejunum but not in ileum, including those for the anticipated targets liver fatty acid binding protein (Fabp1) and lactase-phlorizin hydrolase (LPH), and a surprising induction of genes normally silent in jejunum but highly expressed in ileum, specifically those involved in bile acid transport. Inactivation of Gata4 resulted in an increase in the goblet cell population and a redistribution of the enteroendocrine subpopulations, all toward an ileal phenotype. The gene encoding Math1, a known activator of the secretory cell fate, was induced approximately 75% (P < 0.05). Gata4 is thus an important positional signal required for the maintenance of jejunal-ileal identities in the adult mouse small intestine.
Mol Cell Biol 2006 Dec
PMID:Gata4 is essential for the maintenance of jejunal-ileal identities in the adult mouse small intestine. 1694 Jan 77


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