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 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

Part of the digestive flora in the adaptation to lactose consumption. Lactase activity was determined with adult Wistar rats. Some of which were accustomed to lactose since weaning. For this purpose, the tissue of jejunum, the flora of the ileum, the caecum and the large intestine were examined. When the rats received a high lactose diet, the lactase of the jejunum is more active because of both the intestinal tissue development and a higher production of enzyme by protein unit. But the main source of lactase is the digestive flora of the animal: a lactase flora develops in the ileum, the large intestine and mainly the caecum. The caecum lactase represents about half of the total lactase activity. The flora of the animal which has not consumed lactose since weaning can develop a noticeable lactase activity after 7 hr of incubation in presence of lactose. It is also the caecum flora which shows the greatest capacity of adaptation to lactose.
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PMID:[Role of the digestive flora in adaptation to lactose consumption in rats]. 9 89

The degree of which the ability to absorb lactose can be regained after recovery from an acute episode of severe malnutrition is in doubt. Lactase activity was indirectly assessed by means of a standard lactose tolerance test (2 g lactose per kilogram of body weight) in 71 Peruvian Mestizo infants and children (age 5 to 55 months) who had suffered such an episode. All were studied just before discharge after several months of hospital rehabilitation, during which linear growth and weight gain had accelerated and signs of significant malabsorption of other nutrients had disappeared. Only 39% of the total group had a positive test (delta blood glucose greater than 25 mg/dl); there was a decreasing proportion of positive responders with increasing age. No difference in response attributable to type or severity of malnutrition was found. Comparison of the present data with previous data from children in the same community who had never been acutely malnourished suggests that acute malnutrition may hasten the permanent decline of lactase activity normally expected later in life.
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PMID:Effect of an episode of severe malnutrition and age on lactose absorption by recovered infants and children. 10 90

At various postnatal stages, intestinal epithelial cells were isolated sequentially from villus tip to crypt base by successive EDTA treatments. According to the localization of marker enzymic activities, isolated cells were pooled into three cell compartments: villus (V), lower villus and upper crypt (VC) and crypt (C). Purified brush-border-membrane proteins were separated by 7.5%-polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. Enzymic activities could be assigned to some protein bands: maltase/glucoamylase (protein band 3), sucrase-isomaltase (protein bands 3 and 6), lactase (protein band 5) and alkaline phosphatase (region of protein bands 8 and 9). The findings suggest the following. (1) Sucrase-isomaltase activities appeared in compartment C at 17 days with a simultaneous increase of the pre-existing protein band 3 and appearance of a well-defined protein band in position 6; the enzymic complex remained still present in the crypt cells until adulthood. From the day 21 onwards, sucrase-isomaltase was detected in compartments VC and V. (2) Lactase was only present in the three cell compartments until day 21; at this developmental stage its activity completely disappeared from compartment C, in spite of the persistence of a weak protein band. (3) Alkaline phosphatase activity could be detected as a single peak corresponding to protein band 9 in all three cell compartments until day 21; thereafter it was replaced by two peaks of activity showing a less precise correlation with the well-defined protein bands 8 and 9. In the crypt cells of the adult rat, however, the preweaning situation, which was regularly observed, is an unexpected phenomenon. (4) Maltase and glucoamylase did not display any marked qualitative or quantitative modifications either along the villus-crypt axis or during the period of postnatal development studied. Evidence is given from the present data that each brush-border enzyme investigated has a specific developmental pattern.
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PMID:Developmental pattern of rat intestinal brush-border enzymic proteins along the villus--crypt axis. 10 86

Lactase and maltase, the predominant sugar hydrolases associated with the intestinal brush bordermembrane of the suckling rat, were purified essentially free of the other to near homogeneity (lactase at specific activity 23, maltase at specific activity 58), and their specific physiocochemical properties determined. Antisera prepared to each showed by immunodiffusion a single common precipitin line with pure enzyme and solubilized proteins of the brush border membrane. Brush border membranes were purified 26--35-fold from infant rat intestine. Membranes prepared from 10-day-old rats contained 32% protein, 43% lipid and 25% carbohydrate with lactase and maltase estimated to comprise in excess of 10% and 2%, respectively, of the membrane protein. Immunotitration curves of lactase and maltase showed equivalent antibody binding by the membrane-bound and free enzyme forms. Furthermore, antibody binding to one enzyme did not affect the immunotitration curve or the extractability (by papain or Triton X-100) of the other membrane-bound enzyme. It was concluded that the lactase and maltase molecules are attached singly on the external membrane surface in a spatially independent manner with their antigenic sites as freely available to antibody binding as exhibited by their papain-solubilized counterparts.
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PMID:Sugar hydrolases of the infant rat intestine and their arrangement of the brush border membrane. 11 Mar 47

Mucosal response of alkaline phosphatase, ATPase and disaccharidase (lactase, maltase and trehalase) activities to sex hormones were studied by comparing male and female rats and castrated males and by injecting testosterone into castrated males. Alkaline phosphatase showed a very steep gradient in the small intestine from the oral to the aboral end, whereas ATPase activity in the ileum was still about 50% of that in the duodenum. Both enzymes showed only minor sex variations and weal response to castration. Lactase and maltase had peak activities in the jejunum, but trehalase activity was nearly equally high in the duodenal mucosa as in the jejunum. Jejunal lactase activity was about 50% lower in female than in male rats and castration decreased activity in males to the same low level as found in females. The administration of testosterone to castrated male rats did not enhance activity. Maltase activity showed similar sex variation, although castration was not able to decrease activity during the test period. Trehalase activity was lower in female than in male rats. The administration of testosterone enhance activity in castrated males.
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PMID:Sex variation in the activities of mucosal hydrolytic enzymes in the small intestine of the rat. 12 35

Activities of maltase, sucrase, lactase and acid-beta-galactosidase were studied in jejunum and ileum of term rat fetuses obtained by cesarian section. Female rats were either untreated or injected daily in the last (3rd) week of pregnancy with cortisone acetate (10 or 50 mg/100 g body weight) or L-triiodothyronine (20 or 50 microgram/100 g body weight). Two other control groups were injected with appropriate solvents. Cortisone or T3 treatment to mothers increased sucrase and maltase activity in jejunum and ileum of the offspring. Generally, higher doses of hormone were more effective. Lactase activity was increased by 25% in the jejunum by the higher dose of cortisone. Both doses of cortisone increased ileal lactase. Jejunal acid-beta-galactosidase activity was decreased in fetuses of T3-treated mothers.
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PMID:Effect of cortisone or L-triiodothyronine administration to pregnant rats on the activity of fetal intestinal disaccharidases and lysosomal acid beta-galactosidase. 41 95

The changes with age of intestinal mucosa, protein, lactase, maltase and sucrase were followed in the piglet between day 105 of gestation and 8 weeks after birth. Lactase and maltase activities appeared during fetal life in the whole of the small intestine. Activity of sucrase was recorded after the 1st postnatal week. Lactase activity was high at birth and reached a maximum at 1 week (X 2.5); maltase activity which was low at birth increased to the 8th week (X 143). Activities of all enzymes were low in the duodenum; lactase was most active in the jejumum. Similar activities of maltase and sucrase were found in the two distal parts of the small intestine. Specific activity (related to protein content) of lactase reached a maximum at the end of the 1st week after birth and decreased afterwards. Specific maltase and sucrase activities were higher in the 2nd week, decreased between the 2nd and 4th week and increased afterwards (maltase) or decreased to the 6th--8th week (sucrase).
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PMID:Development of digestive enzymes in the piglet from birth to 8 weeks. II. Intestine and intestinal disaccharidases. 41 3

Fifty children consecutively attending a clinic for coeliac disease co-operated in a trial; 10 found to have flat mucosa were excluded. Forty children of mean age 9.8 years, whose duodenal or jejunal mucosa had returned to normal or near normal appearance after a mean of 5.8 years on gluten-free diets, were put back on normal diets. In 37, mucosal occurred in a mean of 16.9 months (four to 74 months). Four of the 37 had serial biopsies, in which mucosal enzymes (particularly lactase) fell and interepithelial lymphocyte counts rose before the mucosal morphology was regarded as definitely 'coeliac'. Three children had normal mucosal appearance after 58 to 73 months on normal diets, one of whom showed temporary mucosal abnormalities, another having occasionally low enzymes, in both suggesting underlying gluten sensitivity. Lactase suppression and raised IEL counts appear to be sensitive indicators of gluten intolerance. In our experience, a diagnosis of coeliac disease based on severe mucosal damage and a satisfactory response to a gluten-free but milk-containing diet implies a very strong likelihood of permanent or prolonged gluten intolerance, but with a striking variability in its expression.
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PMID:Variability of gluten intolerance in treated childhood coeliac disease. 42 24

Intestinal lactase activity was assessed indirectly in 156 American Indians by measuring breath hydrogen after an oral lactose load. Lactase deficiency was present in 66% of subjects and correlated highly with the percentage of Indian blood. Lactase deficiency was present by the age of 5 years and was unrelated to sex. Most lactase-deficient subjects (81%), but only a minority (23%) of lactase-sufficient subjects, developed symptoms after the oral lactose load, and among lactase-deficient subjects, symptoms occurred more frequently in adults than in children (P = 0.05). Indeed, by history, 53% of lactase-deficient adults, but only 10% of lactase-deficient children under 18 years of age, were aware of milk intolerance. Despite these differences, milk consumption was only slightly less (19 g) in the lactase-deficient subjects than in those with normal lactase activity (25 g) (P less than 0.05). The results indicate that lactase deficiency is a common autosomal genetic trait in the American Indian that becomes manifest in early childhood. Tolerance to dietary lactose appears to decline in the American Indian as he reaches adulthood, but in this population the decline in tolerance had only minor influence on lactose intake.
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PMID:Lactase deficiency: a common genetic trait of the American Indian. 57 36


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