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)

The suitability of the simultaneous azocoupling reaction with 1-naphthyl-beta-D-glucoside and hexazonium-p-rosanilin in the detection of the activity of lactase (or lactase-beta-glucosidase complex) in jejunal biopsies of patients with various forms of the malabsorption syndrome was tested. Results were compared with those obtained with the indigogenic method using 4-Cl-5-Br-3-indolyl-beta-D-fucoside which is the method of choice. Both methods gave identical results as far as the relative intensity of the brush border staining was concerned. The azocoupling method applied in unfixed cold microtome sections can be recommended for the routine diagnostics of the malabsorption syndrome when the indolyl substrate is not available.
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PMID:Suitability of the azocoupling reaction with 1-naphthyl-beta-D-glucoside for the histochemical demonstration of lactase (lactase-beta-glucosidase complex) in human enterobiopsies. 5 35

Rotaviruses are now regarded as important causes of diarrhoea in man, cattle, pigs, mice, and possibly other animals. Characteristically, disease occurs in newborn and young animals, and infection seems limited to the differentiated gut epithelial cells. The major surface polypeptide of the calf scours rotavirus is glycosylated, and highly purified beta-galactosidase (lactase) interacts with the virus in vitro causing removal of the outer shell of the capsid (uncoating). It is suggested that lactase present in the brush border of the intestinal epithelial cell performs a similar function in vivo by acting as a combined receptor and uncoating enzyme for the rotavirus. This hypothesis is consistent with the observations that rotaviruses seem to infect only gut epithelial cells, and that infant animals, whose lactase concentrations are generally higher than those of adult animals, seem more susceptible to rotavirus infections. Implications of the hypothesis include possible new approaches to laboratory cultivation of rotaviruses, which should be more successful in cells selected for surface lactase activity, and the suggestion that the epidemiology of human rotavirus infections may be influenced by the fact that different ethnic groups have different lactase levels (and hence lactose intolerance) in adulthood.
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PMID:Is lactase the receptor and uncoating enzyme for infantile enteritis (rota) viruses? 5 21

Unsubstituted naphthyl substrates were found to be superior to substituted naphthyl, indolyl and hydroxyquinoline substrates for the histochemical demonstration of alpha-mannosidase, alpha-galactosidase, hetero-beta-glycosidase, glucoamylase and sucraseisomaltase, equivalent for beta-N-acetylglucosaminidase and lactase-beta-glucosidase, and inferior for beta-glucuronidase and acid beta-galatosidase. Aldehyde fixation is necessary for the localization of lysosomal glycosidases with naphthyl substrates. 1-naphthyl substrates are suitable for the detection of acid glycosidases in lysosomes and hetero-beta-glysocidase in the cytoplasm of animal cells, and 2-naphthyl substrates can be employed for the demonstration of microvillous glycosidases and for the evaluation of the total activity of soluble glycosidases with semipermeable membranes. When naphthyl substrates are used coupling should be carried out simultaneously and hexazotized pararosaniline is the coupling reagent of choice.
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PMID:Localization of glycoidases with naphthyl substrates. 5 19

An azoindozyl method for the histochemical demonstration of lactase (lactase-beta-glucosidase complex) is described. The incubation medium consists of 5 mg 5-Br-4-Cl-3-indolyl-beta-D-fucoside (dissolved in 0.5 ml N,N-dimethylformamide) and 0.02 ml hexazotized prosaniline in 10 ml 0.1 M citric acid phosphate buffer, pH 6-6.5. By means of this method lactase can be exactly localized in the brush border of the enterozytes in the jejunum of suckling rats. Compared to the corresponding indigogenic method the azoindoxyl reaction proceeds faster and the reaction product is often precipitated more precisely.
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PMID:[Azoindoxyl methods for the histochemical investigation of hydrolases. I. Lactase (lactase-beta-glucosidase complex) (author's transl)]. 6 Mar 19

Dog enterocyte brush border proteins have been studied after a 75% proximal resection of the small bowel. This study was carried on microvillar membrane preparations purified from ileal mucosa sampled before and after regeneration on neighbouring intestinal segments, each animal acting as its own control. After six weeks of regeneration a statistically significant decrease of the following enzyme specific activities was observed: lactase, cellobiase, maltase, sucrase, palatinase, dextranase, trehalase, alkaline phosphatase, aminopeptidase and gamma-glutamyl transferase. Analysis of brush border proteins by polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate have shown after regeneration a decreased rate for the proteins with a molecular weight higher than 100,000 daltons. Modifications of electrophoretic patterns seem to be related to the specific activity decreases observed for brush border enzymes after regeneration, since the molecular weight of these enzymes were found between 116,000 and 285,000 daltons, after gel filtration.
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PMID:Effect of massive proximal small bowel resection on intestinal brush border membrane proteins in the dog. 8 27

Twelve non-pathogenic bacteria and two yeast strains isolated from the duodenal aspirate or mucosa of five children with diarrhoea were tested for their ability to degrade non-human lactase in vitro. Both yeast strains and eleven of the bacterial strains significantly reduced lactase activity. A similar action on human lactase could be a cause of lactose intolerance.
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PMID:Lactase degradation by human enteric bacteria. 8 58

The survival and prognosis of the prematurely born human infant are dependent on a successful transition from the intrauterine to the extrauterine environment. This is largely a consequence of the maturation of sufficient gastrointestinal function to provide adequate nutrition. However, the gastrointestinal tract of the premature infant, and to some extent, of the full-term infant, may be unprepared to provide the requisite absorptive function. Data presented in this symposium emphasize the dissociations in the development of human gastrointestinal function. Morphological maturation is completed early in gestation while glucose absorption increases with gestational age. Sucrase and maltase activities appear early; lactase activity begins to increase at 30 weeks and increases steadily to term. The latter pattern is accompanied by increased production of cortisol and thyroid in the fetus. The intraluminal phase of fat digestion is immature even in the full-term neonate. Both pancreatic secretory function and bile salt metabolism mature postnatally. Despite this relative immaturity, breast milk fat is absorbed with great efficiency by the term infant, and breast milk provides other important influences on intestinal development: mitogenic factor, immunological support, control of intestinal flora. The goals of nutrition support of the premature infant have been to maintain intrauterine growth standards; yet premature infants receiving pooled breast milk from mothers at 40 weeks or more may be given too little protein for their needs. Human milk from mothers of premature infants may be a more appropriate nutrient source. Supplements with higher contents of amino acids may lead to amino acid imbalance or hyperammonaemia. Additional stresses and requirements are imposed by illness or congenital anomalies. While we must apply current research findings to clinical care, we must also extend our knowledge of extrauterine human development. The ultimate measure of success in this field will be the physical and neurological capacities of infants followed prospectively.
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PMID:The immature intestine: implications for nutrition of the neonate. 9 85

Sixty-two strains of yeasts, molds and bacteria were screened for lactase (beta-D-galactosidase) activity. Strains exhibiting the enzyme activity were evaluated for cell yield as well as enzyme units available per litre of the medium, per g cell dry weight and per mg protein of their cell-free extracts. The molds exhibited lowest enzyme activity but highest cell yields, bacteria produced lowest cell yield and maximum enzyme activity. Cultures exhibiting very high activity among yeasts were Saccharomyces fragilis (strain 3217) and among bacteria Streptococcus cremoris (strain H), Lactobacillus bulgaricus (strain RTS and 1373) and Leuconostoc citrovorum (strain 8081).
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PMID:Lactase activity of microorganisms. 9 87

Thirty-six hospital in-patients in London had breath-hydrogen concentrations measured after 50 g lactose were given orally; in 23 or them serial blood glucose concentrations were also estimated. Eight had tropical malabsorption (TM), 14 were Europeans with no detectable disease (normal group) and 14 who also had no detectable disease, were from ethnic groups known to have a very high incidence of genetically determined adult hypolactasia (hl). In 21 of them breath-hydrogen concentrations were also measured after 33.5 g of lactulose were given orally. There was a good inverse correlation between breath-hydrogen production and blood-glucose rise after lactose. Correlations between the first appearance of hydrogen (T) and the area under the hydrogen curve between 0 and 120 min (A) were inversely significant both for lactose and lactulose. Mean T was earlier and mean A greater for lactose compared with lactulose. Correlation between individual values for A after lactase and after lactulose was significant. Indirect measurements of lactase are of no value in either detecting or assessing the severity of TM; that is largely due to the very high incidence of HL in individuals exposed to that disease.
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PMID:Breath hydrogen concentrations after oral lactose and lactulose in tropical malabsorption and adult hypolactasia. 9 20

The presence of antigenic determinants of the following enzymes was detected in enterocytes by the indirect immunofluorescence method: 1. lactase in human biopsy material, 2. sucrase-isomaltase during ontogenesis in the rat. 1. Lactase: The antigenic relationship between rat and human lactase, demonstrated with the isolated enzymes, was utilized for the histochemical localization of human lactase. The indirect immunofluorescence method, using guinea pig antiserum to rat lactase, demonstrated the presence of human lactase in the enterocyte brush border. The usefulness of this method for clinical practice resides in the possibility of detecting enzymatically inactive protein immunologically related to lactase in cases of lactase deficiency, thereby facilitating more detailed classification of these diseases. 2. Sucrase-isomaltase: Guinea pig antiserum to rat sucrase-isomaltase (SI) was prepared. It was used to demonstrate antigenic determinants of the enzyme in the enterocyte brush border of the rat during ontogenesis. Structural SI protein is already present in 3-day-old rats, whereas enzyme activity can first be demonstrated histochemically from the 11th day of life and biochemically, in vitro, not until about the 18th day. We consider that this technique can be used for studying the biogenesis of membrane-bound enzymes.
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PMID:Immunohistochemical localization of intestinal glycosidases. 9 28


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