Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Supragingival human dental plaque was collected from patients with evidence of caries. The plaque was frozen and stored at -20 degrees C. Pooled plaque was homogenized in acetate buffer pH 5.0 in an ice-water bath. By incubating the homogenate at pH 5.0 with [U-14C]-sucrose the formation of glucose and fructose was followed. Incubation in acetate buffer at pH 5.0 eliminated the glycosyltransferase activities and the glycolytic pathway. Normal Michaelis-Menten kinetics were observed until about 40 mM sucrose. At higher concentration of sucrose, excess substrate inhibition occurred. Storage of the homogenate at -20 degrees C resulted in decrease of the invertase activity with time.
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PMID:Method for determination of invertase activity in homogenates of human dental plaque. 695 Dec 45

Both corticosterone and T4 have been previously implicated as causal factors in the ontogenic increases in jejunal sucrase and maltase activities during the third week of life in the rat. Furthermore, it is known that the administration of exogenous T4 during the developmental period causes significant increases in serum corticosterone concentrations. To determine whether the effects of T4 on sucrase and maltase are secondary to the corticosterone rise, we examined the effect of T4 administration in adrenalectomized (adX) pups. Serum corticosterone was measured in all operated animals. Some of the adX pups had substantial concentrations of circulating corticosterone. In adX pups with serum corticosterone levels below 0.1 microgram/dl, there was no effect of T4 on either maltase or sucrase activity. We also studied the effect of propylthiouracil-induced hypothyroidism on sucrase and maltase. At 21 days of age, both enzyme activities were significantly reduced in hypothyroid pups. Injections of either T4 or cortisone acetate were equally effective in restoring activities to normal. For sucrase, there was no further increase in activity when both hormones were administered. For maltase, the combined treatment gave activities that were significantly higher than those with either hormone alone. We conclude that for both sucrase and maltase, the effects of changes in thyroid status are primarily due to the accompanying changes in serum corticosterone. The normal rate of development of both enzymes appears to be principally under glucocorticoid control, although for maltase, T4 may have a facilitory action.
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PMID:Relative importance of corticosterone and thyroxine in the postnatal development of sucrase and maltase in rat small intestine. 704 75

The development and distribution of peptidase activity in mucosal homogenates of rat small intestine has been investigated. Substrates used were glycyl-L-leucine (GL), L-seryl-L-methionine (SM), and L-leucyl-glycyl-glycine (LGG). During the first 2 weeks of life there was high peptidase activity toward GL and SM in the distal regions of the small intestine. In the third postnatal week, activity in the distal small intestine toward GL and SM decreased, while activity in the proximal small intestine increased. In contrast, there was no difference in activity toward LGG along the length of the small intestine, nor was there a developmental change. Activity toward all three substrates was not affected by cortisone acetate treatment. However, the classical effect of glucocorticoids on sucrase activity and body weight was observed. All peptidases studied showed maximal activities at neutral pH, indicating that they were not lysosomal in origin. Activity towards GL and SM was predominantly located in the cytosol. It is suggested that these dipeptidase activities play a role in the terminal steps of protein digestion following pinocytosis and lysosomal hydrolysis.
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PMID:Postnatal development of peptidase enzymes in rat small intestine. 718 19

The beta-fructofuranosidase preparation was mechanically immobilized. The enzymic preparation with fillers was applied to spheric particles of silicagel by rolling in the pelleting apparatus and the particles obtained were coated with semipermeable polyvinyl acetate film. As compared to the soluble enzyme the temperature optimum of the immobilized preparation is 10-15 degrees C shifted towards an increase and pH-optimum remains unchanged. The regions of pH-stability of immobilized and free beta-fructofuranosidases coincide. An increase in the apparent Km due to immobilization evidences for a diffuse control in kinetics of the preparation action, which is also confirmed by the presence of the induction period in the "reaction product in external solution-time" curve.
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PMID:[Properties of mechanically immobilized beta-fructofuranosidase]. 725 39

The effect of vitamin C deficiency on the digestive and absorptive functions of the gut has been investigated in guinea pigs. The absorption of D-glucose was significantly elevated, but that of L-leucine, L-alanine and L-lysine considerably depressed in the intestine of scorbutic guinea pigs compared to controls. The intestinal transport of vitamin B12 was also diminished. Activities of sucrase and alkaline phosphatase on the brush border were enhanced, but that of leucine aminopeptidase markedly reduced in scorbutic animals compared to controls. Maltase activity was unaffected in vitamin C deficient animals. Chemical analysis of the brush borders isolated from scorbutic animals revealed a considerable decrease in membrane protein, total lipids, phospholipids, and free cholesterol contents compared to control animals. In vivo 2-(14)C-acetate incorporation into membrane lipids suggested that the observed decrease in lipid components of the scorbutic membranes is due to reduced synthesis. Administration of ascorbic acid to scorbutic animals ameliorated the intestinal aberrations observed in scurvy.
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PMID:Effect of vitamin C deficiency in guinea pigs on intestinal functions and chemical composition of brush border membrane. 730 86

Enzyme (uricase or invertase) was entrap-immobilized in gel fibre of cellulose acetate-TiO2 by using a gel formation of cellulose acetate and titanium iso-propoxide. The fibre is stable in common solvents, phosphate solution and electrolyte solution over a wide range of pH 4-10. The pH maximum of activity shifts to a more alkaline side compared to free enzyme, reflecting an amphoteric property of TiO2.
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PMID:Preparation of fibre-entrapped enzyme using cellulose acetate-titanium-iso-propoxide composite as gel matrix. 776 33

We have investigated the expression of protein kinase C (PKC) and protein kinase A (PKA) during the phases of growth and differentiation of the human colon carcinoma Caco-2 cells. We studied whether differentiation correlated with the responsiveness to cAMP and with an increased transport of the catalytic subunit of PKA into the nucleus. Also, we evaluated whether this phenomenon was affected by PKC activity. High levels of activated PKC were found in the plasma membranes of replicating cells. When the cells began to differentiate, plasma membrane-activated PKC decreased, while the cytosolic fraction increased. On the contrary, PKA holoenzyme increased during differentiation, along with the transport of its catalytic subunit into the nucleus. Both types I and II kinase A holoenzymes increased during differentiation, with maximal type II activity found when cells were fully differentiated. In replicating preconfluent cells, the inhibition of PKC by high dose phorbol 12-myristate 13-acetate or sphingosine increased the amount of both PKA catalytic subunit in the nucleus and sucrase activity. During differentiation, 8-Bromo-cAMP increased PKA catalytic subunit in the nucleus and apoliprotein A1 mRNA levels. These effects were inhibited by low-dose phorbol 12-myristate 13-acetate, which activates PKC in the plasma membranes. Our data suggest that PKC is activated in proliferating Caco-2 cells. The inhibition of PKC induces the transport of PKA catalytic subunit into the nucleus and the expression of the differentiation markers. Differentiated Caco-2 cells show a lower activation of PKC and an increased transport of the catalytic subunit of PKA into the nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The enterocyte-like differentiation of the Caco-2 tumor cell line strongly correlates with responsiveness to cAMP and activation of kinase A pathway. 781 34

The invertase activity of intact Saccharomyces cerevisiae submitted to freezing-thawing was affected by pH, the chemical nature of the buffer, and the freezing cooling rate (CR), leading in some cases to a complete invertase inactivation (acetate buffer, pH 4.0, CR = 0.5 degree C/min). Once established under adequate freezing conditions the invertase activity remained unchanged after freeze-drying. Nevertheless, in some cases the cell-growing capability after freeze-drying diminished around 70%, mainly if the frozen cell suspension was attained through freezing carried out at CR = 0.5 degree C/min. Water sorption isotherms of freeze-dried samples (freeze-dryer Edwards L-4KR; 30 degrees C and 0.1 mB) were determined at 10 and 25 degrees C. The monolayer moisture content (MMC) at each temperature (12.7 and 3.71 for 10 and 25 degrees C, respectively) was calculated from isotherms by applying BET and GAB models. Freeze-dried yeast with water activity (Aw) between 0 and 0.33 (about the MMC value) maintained at 25 degrees C for 235 days and at 89 degrees C for 15 min retained at least 85% of its original invertase activity (IA), whereas samples with Aw > MMC lost at least 60% of its IA. X ray diffraction showed that the freeze-dried cake before and after storage presented an amorphous structure.
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PMID:Effect of moisture content on the invertase activity of freeze-dried S. cerevisiae. 792 95

Polyamines appear to have an important role in postnatal growth of the rat intestine. In the present study, we examined the effect of spermidine on the maturation of the intestine and on its ability to exclude macromolecules. Two litters of Sprague-Dawley rat pups were assigned to one of four experimental groups. These groups received, on Days 7, 8, and 9, either (a) saline by gavage; (b) spermidine, 0.9 mg (6 mumol) by gavage; (c) cortisone acetate, 3.5 mg i.p.; or (d) saline i.p. On Day 10, animals were fed by gavage with a mixture of bovine serum albumin (BSA; 2 mg/g) and the gamma-globulin fraction of mouse antiovalbumin (anti-OVA) antiserum (1 mg/g) and were bled 4 h later. Intestinal tissues were processed for histologic examination, sucrase determination, and identification of neonatal intestinal Fc receptor (FcRn) by Western blot. Serum immunoreactive BSA (iBSA) and mouse IgG1 and IgG2a anti-OVA antibodies were estimated by enzyme-linked immunosorbent assay. Sucrase activity was elevated in cortisone- and spermidine-treated compared to control rats. iBSA and anti-OVA were significantly reduced in cortisone-treated compared to control rats but were not diminished significantly in the spermidine-treated animals. A decrease in the neonatal intestinal Fc receptor was apparent in the spermidine-fed group; cortisone produced a large reduction in FcRn. Spermidine-fed animals showed morphologic evidence of maturation, with loss of giant vacuoles in the distal intestine; cortisone did not produce significant changes in morphology.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of the polyamine, spermidine, on intestinal maturation and dietary antigen uptake in the neonatal rat. 796 74

An acid trehalase-sucrase aggregate was purified (by 780-fold) from Saccharomyces cerevisiae, following conventional protein purification techniques, to an apparent yield of 18.5%. The aggregate was electrophoretically homogeneous but contained 175, 90, 68, 60, 40 molar mass (kDa) bands on SDS-electrophoresis. The purified aggregate had a specific activity (acid trehalase) of 22 U/mg; a Km value of 5.0 mM but contained 3-times more sucrase activity. Only sucrose and trehalose were hydrolysed by this aggregate and both activities were inhibited by acetate or phosphate. Temperature and pH optima for trehalose hydrolysis appeared to be 40-45 degrees C and 5.0, respectively. The purified aggregate appeared to be disaggregating spontaneously resulting in inactivation of both enzymes, which was enhanced either at pH 3.5 or at pH 7.0. Separation of acid trehalase from the aggregate by hydrophobic interaction chromatography resulted in inactivation. Rechromatography (HPGPLC) of the purified aggregate also gave disaggregation as well as inactivation of both enzymes. Disaggregated acid trehalase and sucrase contained 20-fold and 13-fold lower specific activities, respectively, and appeared to be unstable. Based on these observations we suggest that acid trehalase is stabilised by aggregation with sucrase.
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PMID:Characterisation of an acid trehalase of Saccharomyces cerevisiae present in trehalase-sucrase aggregate. 864 14


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