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)

Purifications of mouse intestinal brush-border membranes from control explants and scrapings of intestinal mucosa have been compared. Based on the specific activity of sucrase used as a specific marker of these membranes, higher purification factors were obtained with control explants (24.7 +/- 0.9) as compared with scrapings of intestinal mucosa (14.8 +/- 0.9). However, similar patterns of proteins and enzymes were obtained by sodium dodecyl sulfate (SDS) - polyacrylamide gel electrophoresis after membrane solubilization by 2% SDS at room temperature. After 24 h of culture, higher molecular weight species of maltase-glucoamylase-isomaltase (band 4), alkaline phosphatase (bands 9-10), and trehalase (band 17) have been observed. Enzyme species appearing in the particulate fraction of culture media were, however, identical with those found at the brush-border membrane level in control explants, except for trehalase. These results are interpreted by considering the possible adsorption of serum components to brush-border membrane proteins. It thus appears that the membrane proteins and enzymes released in the media during organ culture are identical with those synthesized in the tissue in vitro or in vivo.
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PMID:Proteins and enzymes of the brush-border membrane of mouse intestine: influence of organ culture on gel electrophoretic patterns. 710 21

Suspensions of sequentially isolated villus and crypt cells were obtained in order to study certain biochemical changes associated with differentiation of epithelial cells in the small intestine of the mouse. Microscopic observation of the various cell fractions reveals that the epithelial cells detach as individual cells or small sheets of epithelium from the tip to the base of the villus, whereas cells in the crypt regions are separated as entire crypt units. The isolated cells retain their ultrastructural integrity as judged by electron miscroscopy. Chemical characterization of the various fractions shows that the total cellular protein content, expressed in activity per cell, remains relatively constant throughout the villus region followed by a noticeable drop in the crypt zone. On the other hand, sharp variations in values of cell DNA content are observed in the crypt zone depending on the reference of activity being used. Activity profiles of several brush border enzymes confirm the biochemical changes that occur during the migration of cells from the crypt to the villus tip, as observed in other species, with maximum activity of sucrase in the mid-villus region, of glucoamylase, trehalase, lactase and maltase in the upper third region, and of alkaline phosphatase at the villus tip. Forty-eight-hour suspension cultures of cell fractions corresponding to cells at the base of the villus and crypt zones show a moderate decrease in protein and enzyme activities to approximately 70% of their original value, with DNA content remaining stable throughout the incubation period. The use of biochemical activities as indicators of cellular integrity during cell culture is discussed.
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PMID:Characterization of isolated villus and crypt cells from the small intestine of the adult mouse. 741 92

The activities of the disaccharidases lactase, maltase, sucrase and trehalase were examined in gerbils during Giardia lamblia infections. In a primary infection with trophozoites, the activities of all four enzymes were reduced from day 10 post-infection (p.i.) and remained at low levels well past the elimination phase of the infection. However, during a challenge infection, the disaccharidase decreases were short-lived, with impairments being seen only on days 2 and/or 4 post-challenge (p.c.). Sucrase activity was not affected by a challenge infection. When 0.1 mg of a soluble extract of G. lamblia trophozoites was used to challenge gerbils previously exposed to the live parasite, the pattern and duration of enzyme deficiencies were comparable with those observed after the challenge with the live parasite. In addition, decreasing the extract dose used to challenge the gerbils led to smaller disaccharidase deficiencies. G. lamblia-infected gerbils were also challenged with a soluble extract of Entamoeba histolytica trophozoites, and this had no effect on the disaccharidase activities. Therefore, the presence of the intact parasite was not necessary to induce enzyme reductions in immune animals. In addition, the effects seen during the secondary infection were parasite-specific and may have involved the host's immune response to Giardia antigens. Immune gerbils were further challenged with the in vitro-released excretory/secretory products of G. lamblia. Under our experimental conditions, disaccharidase activities were found to be affected by these products in a manner that was inconsistent with the results of the live parasite challenge, and this merits further study.
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PMID:Disaccharidase deficiencies in Mongolian gerbils (Meriones unguiculatus) protected against Giardia lamblia. 747 50

The effects of oat saponins (a mixture of avenacosides A and B) and dietary fibre (cellulose and guar gum) on the disaccharidase activities in the proximal small intestine of the rat were investigated. The influence of avenacosides A and B on the activity of disaccharidases and alpha-amylase (EC 3.2.1.1) was also studied in vitro. In vivo, oat diets with three avenacoside contents (negligible, normal and twice normal) were used. No significant differences in sucrase (EC 3.2.1.48), maltase (EC 3.2.1.20), trehalase (EC 3.2.1.28) and lactase (EC 3.2.1.21) activities were found between the oat groups after 19 d feeding. The rats that were given cellulose tended to have higher disaccharidase activities compared with the other groups. The avenacosides inhibited the lactase activity significantly in vitro while no or small effects on the other disaccharidases were found. In contrast, the in vitro hydrolysis of starch by alpha-amylase was increased in the presence of saponins, probably due to their detergent effect. Thus, the in vitro studies showed that the avenacosides could influence the enzyme activities. In vivo, these effects are probably minor due to the low avenacoside concentrations found in oats.
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PMID:Effect of oat saponins and different types of dietary fibre on the digestion of carbohydrates. 754 40

Mechanisms of enzyme inhibition by trehazolin, a new inhibitor of trehalase (Ando et al. (1991) J. Antibiot. 44, 1165), were investigated using purified soluble silkworm trehalase and other glycosidases. Trehazolin inhibited trehalase with an IC50 value of 27 nM, whereas some other exo-alpha-glucosidases were inhibited only weakly, with IC50 values ranging from 7 to 370 microM. Other glycosidases tested were not inhibited by 500 microM trehazolin. The inhibition of trehalase by trehazolin was competitive with respect to trehalose. A notable feature of the inhibition was a slow progression of the association and dissociation of the enzyme-inhibitor complex. Preincubation of the enzyme and the inhibitor at 37 degrees C potentiated the inhibition by 10-times in a time-dependent manner up to 6 h. Dialysis of the inactivated enzyme recovered the enzymatic activity very slowly, and the rate constant for the dissociation at 37 degrees C was (7.3).10(-2) h-1. Trehalamine, a deglucosylated form of trehazolin, inhibited both silkworm trehalase and exo-alpha-glucosidases only weakly. The inhibition of trehalase by trehalamine was reversible. Rat isomaltase inhibition by trehazolin and sucrase inhibition by trehalamine were also reversible. Taken together, trehazolin is a specific slow, tight-binding inhibitor of trehalase, and the glucose moiety of the inhibitor is essential to the tight binding.
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PMID:Trehazolin, a slow, tight-binding inhibitor of silkworm trehalase. 759 47

To elucidate the contribution of host and parasite factors in induction of small-intestinal disaccharidase deficiency in giardiasis, we determined the activity of four enzymes in male and female C57BL/6 mice infected with Giardia muris. Both male and female mice exhibited significant disaccharidase deficiency as shown by decreases in the activities of lactase, sucrase, trehalase and maltase on day 10 after infection. However, by 20 days after infection the females had normal enzyme activities, whereas those in males remained significantly reduced. Prolonged disaccharidase deficiency in the males was related to the course of the primary infection where males had higher parasite loads in the small intestine than did females on day 20 after infection. By day 40 after the primary infection the enzyme activities had returned to normal levels and were similar in male and female mice. Secondary exposure of mice to either the infective cysts or a crude extract of the trophozoites caused disaccharidase deficiency. The females had lower activities of sucrase and trehalase as compared with males after the challenge. Thus, during the primary infection, disaccharidase deficiency was strongly associated with parasite number, whereas after challenge infections the more resistant females had lower enzyme activities in the small intestine than did males.
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PMID:Disaccharidase activity in male and female C57BL/6 mice infected with Giardia muris. 773 22

Exogenous glucocorticoids administered during the first two postnatal weeks are capable of eliciting precocious maturation of the rat intestine. However, it is not known whether this represents an alternative developmental pathway or is essentially an advancement of normal ontogeny. The goal of the present study was to address this question using the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU), which is known to selectively inhibit differentiation in a number of tissues. Intestinal development was assessed by following changes in sucrase, trehalase, glucoamylase, and lactase activities. The first experiment assessed whether BrdU has any influence on the cellular differentiation that occurs continuously along the crypt-villus axis. After administration of BrdU to suckling and mature animals, there was no effect on lactase and sucrase activities, respectively. Thus BrdU does not inhibit crypt-villus differentiation in either the suckling or mature jejunum. In the second experiment, dexamethasone was used to induce precocious maturation in the rat jejunum on day 10. BrdU treatment significantly inhibited glucocorticoid-induced elevation of sucrase, trehalase, and glucoamylase but had no effect on the lactase activity. In contrast, treatment with BrdU during normal development significantly accelerated the ontogenic rise of sucrase and trehalase as well as the ontogenic decline of lactase. The acceleration of development was also seen in adrenalectomized rats, indicating that it is the glucocorticoid-independent component of normal intestinal ontogeny that is activated by BrdU. The opposite effect of BrdU on glucocorticoid-induced precocious maturation suggests that such maturation involves different molecular mediators than normal ontogeny.
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PMID:Distinguishing normal and glucocorticoid-induced maturation of intestine using bromodeoxyuridine. 784 Jan 97

Trehazolin, a new trehalase inhibitor isolated from the culture broth of Micromonospora, was reported to be a highly specific inhibitor for porcine and silk worm trehalases with IC50 values of 5.5 x 10(-9) and 3.7 x 10(-9) M, respectively (O. Ando, H. Satake, K. Itoi, A. Sato, M. Nakajima, S. Takashi, H. Haruyama, Y. Ohkuma, T. Kinoshita, and R. Enokita (1991) J. Antibiot. 44, 1165-1168). We also found that trehazolin is a very powerful and quite specific inhibitor against purified pig kidney trehalase, giving an IC50 value of 1.9 x 10(-8) M. Lineweaver-Burk plots showed that this compound was a competitive inhibitor of the trehalase. However, even at concentrations of 200 micrograms/ml, trehazolin did not inhibit the rat intestinal maltase or sucrase, yeast alpha-glucosidase or almond beta-glucosidase. Validoxylamine A and validamycin A, two other trehalase inhibitors, showed potent competitive inhibition against purified pig kidney trehalase, with IC50 values of 2.4 x 10(-9) and 2.5 x 10(-4) M, respectively. On the other hand, validoxylamine A was almost inactive against rat intestinal sucrase and maltase, with some inhibition being observed at millimolar concentration. A number of other glucosidase inhibitors, such as MDL 25637, castanospermine, and deoxynojirimycin were also tested against the purified trehalase and showed reasonable inhibitory activity.
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PMID:Inhibitors of pig kidney trehalase. 786 39

The effects of epidermal growth factor (EGF) on neonatal intestines were examined in the rat. In 5-day-old rats, sucrase, trehalase, alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (gamma-GTP) activities in the small intestines were significantly increased after subcutaneous injection of EGF for 3 days (1 microgram/rat/day). gamma-GTP activity was also accelerated after oral EGF administration (2 micrograms/rat/day). Small intestines of 12-day-old rats injected with EGF for 10 days (1 microgram/rat/day) were significantly heavier than those of controls. These results suggest that EGF influences neonatal growth improving enlargement and functional development of their intestines.
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PMID:Effects of epidermal growth factor on neonatal growth of rat intestines. 791 Jul 14

Leishmania donovani promastigotes were collected, washed, resuspended in buffer, and assayed for sucrase activity. No activity was observed in the intact washed cells, but activity was measurable when the cells were permeabilized with Triton X-100. Intracellular sucrase activity was highest in promastigotes grown at pH 7.4, somewhat lower in promastigotes grown at pH 5.5, and significantly lower in "amastigotes" grown at pH 5.5. No trehalase, lactase, or maltase activities were observed. Assay of the medium in which the cells had grown showed that most the sucrase activity was extracellular, i.e. was secreted into the medium during growth.
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PMID:Secretion of sucrase by Leishmania donovani. 804 86


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