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)

The intestinal microvilli of fetal origin in human amniotic fluid were purified by Ca2+ precipitation of contaminating organelles followed by differential centrifugation of microvillar membranes. In the purified preparation, the specific activity of the microvillar marker-enzymes maltase and sucrase increased about 77-fold over that in cell-free amniotic fluid. Significant contamination of the purified preparation by endoplasmic reticulum (microsomes) and lysosomes was ruled out on the basis of a low content of the marker enzymes glucose-6-phosphatase (microsomes) and acid phosphatase (lysosomes). Amniotic fluid microvilli contain typical enzymes of the fetal intestine including maltase, sucrase, trehalase, alkaline phosphatase and gamma-glutamyltransferase, and their morphology by electron microscopy resembles that of vesiculated intestinal microvilli. Prenatal detection of genetic diseases due to a deficiency of a protein expressed in these membranes or associated to abnormal microvilli seems feasible.
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PMID:Fetal intestinal microvilli in human amniotic fluid. 302 83

Synchronous cultures of Saccharomyces cerevisiae prepared by selection of small unbudded cells from an elutriating rotor were used to measure trehalase activity during the cell cycle. After the small cells had been removed from the rotor, the remainder was used to prepare asynchronous control cultures. Both synchronous and control cultures were studied for two cell cycles. In asynchronous cultures the trehalase activity of crude cell lysates rose continuously. In synchronized populations trehalase activity increased from the beginning of budding onwards. However, around the period of cell division the enzyme activity dropped rapidly but transiently by more than 5-fold. The same changes were found during the second budding cycle. Measurements of invertase and glucose-6-phosphate dehydrogenase activities in the same synchronous and asynchronous cultures revealed a continuous increase for both enzymes. Incubation of cell lysates with cAMP-dependent protein kinase before assaying for trehalase resulted in a 2-fold enhancement of enzyme activity in asynchronous control cultures. In synchronized cells this treatment also led to a significant stimulation of trehalase activity, and largely abolished the cell-cycle-dependent oscillatory pattern of enzyme activity. These results suggest that the activity of trehalase during the cell cycle is regulated, presumably at the post-translational level, by a phosphorylation-dephosphorylation mechanism.
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PMID:Regulation of trehalase activity during the cell cycle of Saccharomyces cerevisiae. 305 78

1. The disaccharidase activities of the small intestines of American alligators (Alligator mississippiensis) were studied in epithelial scrapes and brush-border membrane preparations. 2. Maltase, isomaltase and trehalase activities were found. Activities of these enzymes were higher in the proximal small intestine and decreased distally. 3. Disaccharidase activities were enriched 12-15 times in brush-border membrane preparations, compared with mucosa/enterocyte crude homogenates and were co-enriched with the brush-border membrane marker alkaline phosphatase. 3. The pH optima were: maltase 6.5; isomaltase 5.6; and trehalase 5.8. The Q10 of maltase, the most active enzyme, was equal to 1.82. 4. In reptiles, as in mammals, disaccharidase activities may be correlated with feeding habits. The co-occurrence of sucrase and isomaltase may not be a common feature of vertebrates.
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PMID:Intestinal brush border membrane-bound disaccharidases of the American alligator, Alligator mississippiensis. 306 78

Hydrocortisone administration to infant rats enhanced cellobiase and maltase activities and induced precocious expression of sucrase and trehalase activities along the length of the small intestine. These activity changes reflected proportional concentration increases in the enzymes lactase (EC 3.2.1.23), maltase/glucoamylase (EC 3.2.1.20) and sucrase-isomaltase (EC 3.2.1.48/10). Administration of an equivalent tracer dose of [3H]leucine (by body weight) to control and hydrocortisone-treated infant rats resulted in greater accumulation of label in the carbohydrase pools of the treated rats, suggesting their increased de novo synthesis. The increased concentrations of lactase and maltase/glucoamylase induced by exogenous hydrocortisone were matched by the presence of corresponding greater amounts of label in their brush border pools. Accumulation of label in each of the lactase, maltase/glucoamylase and sucrase-isomaltase pools was generally similar in the hydrocortisone-treated rats, suggesting equivalent stimulation of their synthesis as a group by the humoral agent. The turnover rates of the carbohydrases as a group were found to be similar and did not appear to differ in control and hydrocortisone-treated rats. Total protein synthesis rates were slightly greater in the intestine of the hydrocortisone-treated group of rats.
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PMID:Effects of hydrocortisone on carbohydrase concentrations, de novo synthesis and turnover patterns in immature rat intestine. 308 73

Graft-versus-host reaction (GvHR) was induced in neonatal mice to produce crypt hyperplasia with and without stunted villi. Lactase activity was measured along individual villi of control and GvHR mice using quantitative cytochemistry. Lactase activity increased in control mice as enterocytes migrated over the lower part of the villus. This increase was followed by a period when lactase activity remained approximately constant. Effects produced by GvHR on this normal profile of development included an extension of the distance on the villus over which enterocytes could continue to increase lactase activity, a reduction in the time needed for an enterocyte to express lactase activity at maximal rate, and an overall decrease in the maximal lactase activity expressed by mature enterocytes. These effects have been quantified by fitting logistic curves to the experimental data. Parallel biochemical analyses of intestinal homogenates showed sucrase, isomaltase, trehalase and maltase activities to increase markedly 7-8 days after the injection of parental spleen cells. Attention is drawn to similarities between these results and steroid induced precocious development of intestinal function in neonatal mice.
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PMID:Selective effects of graft-versus-host reaction on disaccharidase expression by mouse jejunal enterocytes. 308 82

Suckling rats were treated every 8 h by intragastric instillation of 16,16-dimethyl prostaglandin E2 (PG) in a dose of 25 micrograms kg-1 (PG25), or 100 micrograms kg-1 (PG100), or saline from postnatal day 7-11. PG increased small intestinal villus length and crypt depth, most markedly in the duodenum, leading to a mucosal height of 543 +/- 24 microns after saline, 670 +/- 26 microns after PG25 and 823 +/- 40 microns after PG100. In the proximal small bowel, PG100 raised the mean activities of sucrase by 439%, maltase by 98%, trehalase by 584%, lactase by 58% and alkaline phosphatase by 76%. In the distal small intestine, only sucrase and trehalase activities were stimulated whereas other enzymes were depressed. PG25 caused similar but less pronounced changes of enzyme activities. Eight hours after both the last PG25 and the last PG100 dose, plasma gastrin and corticosterone levels were decreased while thyroxine remained unchanged. The effect of a single dose of 100 micrograms kg-1 PG or saline was also tested on 5- and 11-day-old rats; they were killed 16 h after PG administration. An increase in villus length occurred along the entire small intestine of rats treated on day 5, and also in the ileum of rats treated on day 11. In the proximal intestine, maltase and trehalase were stimulated after early and late treatment and, in addition, sucrase and lactase after late treatment. Serum corticosterone levels were found to be significantly higher 2-6 h after PG100 than in the controls and then decreased gradually.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of 16,16-dimethyl prostaglandin E2 on small intestinal mucosa in suckling rats. 311 65

The results of studies on disaccharidase activities and on intestinal absorption in cases of complete and incomplete congenital small bowel obstruction are presented. Assays of the activities of maltase, isomaltase, sucrase, trehalase, and lactase have been performed on biopsy specimens taken at the time of surgery. In specimens taken from above the site of obstruction, the activities are reduced for all disaccharidases, and are particularly low for trehalase and lactase. There was no difference between the cases with complete and incomplete obstruction. Distal to a complete obstruction, trehalase and lactase were reduced, whereas in cases of incomplete obstruction, the activities of all disaccharidases were within what is considered normal in the reference material. Two months after surgery, the disaccharidase activities were found to be normal. One month after surgery, the absorption of glucose and vitamin A was markedly impaired in cases with complete obstruction, whereas that of D-xylose was not significantly reduced from normal. In cases with incomplete obstruction, the results did not differ from those found in normal infants. The fact that failure to thrive is common during the first months after birth in patients with congenital intestinal atresia, even when surgery is successful, may be explained by deficient intestinal absorption, particularly in patients with complete obstruction.
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PMID:Disaccharidase activities and intestinal absorption in infants with congenital intestinal obstruction. 312 31

1. The intestinal disaccharidase activities of a suckling crabeater seal were investigated. 2. Lactase, maltase, isomaltase and cellobiase activities were readily detected but trehalase and sucrase activities were absent. 3. The intestinal homogenates were separated into a soluble (S2) fraction and a particulate brush border (P2) fraction. The lactase activities of the two fractions had different properties corresponding to those of an acid and a neutral beta-galactosidase respectively. Approximately two-thirds of the total lactase activity measured at pH 6.0 was due to the acid beta-galactosidase. 4. The isomaltase and cellobiase activities were found almost exclusively in the particulate fractions but about one third of the maltase activity was in the S2 fraction. This soluble maltase activity appeared to be due to an acid maltase.
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PMID:Intestinal lactase and other disaccharidase activities of a suckling crabeater seal (Lobodon carcinophagus). 313 70

The influence of epidermal growth factor (EGF) on the differentiation and proliferation of human fetal jejunum was studied in organ cultures. Fetal intestine (11-14-wk gestation) was cultured for 5 days at 37 degrees C in serum-free Leibovitz L-15 medium alone or supplemented with 25, 50, and 100 ng EGF/ml culture medium. The addition of hormone did not modify the morphology of the intestinal explants. Biochemical studies revealed that lactase activity was significantly increased with the addition of 50 and 100 ng EGF/ml culture medium. On the other hand, the increase in sucrase, trehalase, and glucoamylase activities that normally occurs during the culture was repressed in the presence of increasing concentrations of EGF. Deoxyribonucleic acid synthesis was significantly decreased after 5 days of culture even in the presence of the lowest EGF concentration used. Concomitantly, the labeling index of the epithelial cells dropped drastically in the presence of EGF. The EGF-induced variation in DNA synthesis was already evident within 24 h of culture, whereas enzymic modifications occurred only between the third and fifth day of culture. The simultaneous addition of EGF and hydrocortisone (50 ng/ml) did not reveal any synergistic action between the two hormones on the hydrolytic activities of the brush border. However, EGF did inhibit hydrocortisone-stimulated DNA synthesis. The present work provides for the first time some basic data on the influence of EGF on brush border hydrolytic activities and on epithelial cell proliferation of human fetal jejunum. These observations strongly suggest that EGF plays an important role in the fetal development of the human gastrointestinal tract.
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PMID:Biologic effects of epidermal growth factor in human fetal jejunum. 325 52

Acid trehalase was purified from the yeast suc2 deletion mutant. After hydrophobic interaction chromatography, the enzyme could be purified to a single band or peak by a further step of either polyacrylamide gel electrophoresis, gel filtration, or isoelectric focusing. An apparent molecular mass of 218,000 Da was calculated from gel filtration. Polyacrylamide gel electrophoresis of the purified enzyme in the presence of sodium dodecyl sulfate suggested a molecular mass of 216,000 Da. Endoglycosidase H digestion of the purified enzyme resulted after sodium dodecyl sulfate gel electrophoresis in one distinct band at 41,000 Da, representing the mannose-free protein moiety of acid trehalase. The carbohydrate content of the enzyme was 86%. Amino acid analysis indicated 354 residues/molecule of enzyme including 9 cysteine moieties and only 1 methionine. The isoelectric point of the enzyme was estimated by gel electrofocusing to be approximately 4.7. The catalytic activity showed a maximum at pH 4.5. The activity of the enzyme was not inhibited by 10 mM each of HgCl2, EDTA, iodoacetic acid, phenanthrolinium chloride or phenylmethylsulfonyl fluoride. There was no activation by divalent metal ions. The acid trehalase exhibited an apparent Km for trehalose of 4.7 +/- 0.1 mM and a Vmax of 99 mumol of trehalose min-1 X mg-1 at 37 degrees C and pH 4.5. The acid trehalase is located in the vacuoles. The rabbit antiserum raised against acid trehalase exhibited strong cross-reaction with purified invertase. These cross-reactions were removed by affinity chromatography using invertase coupled to CNBr-activated Sepharose 4B. Precipitation of acid trehalase activity was observed with the purified antiserum.
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PMID:Purification and characterization of acid trehalase from the yeast suc2 mutant. 328 51


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