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)

NMRI mice immunosuppressed with dexamethasone followed by challenge intraesophageally with axenic Giardia lamblia (Portland I) trophozoites had severe infection in terms of the trophozoite counts in the jejunum. Although the immunosuppressive treatment with cortisone itself resulted in a deleterious effect on brush border membrane enzymes, the decline in disaccharidases (sucrase, maltase, and lactase) and alkaline phosphatase was highly significant (P less than 0.001) following G. lamblia infection. The alterations in enzymatic activity in immune intact but infected animals demonstrated the potential of the parasite itself to cause damage to the brush border membrane. We believe that individuals with underlying immunodeficiency, upon infection with G. lamblia, may have increased damage of the brush border membrane, leading to severe malabsorption.
Dig Dis Sci 1988 Sep
PMID:Giardia lamblia infection in immunosuppressed animals causes severe alterations to brush border membrane enzymes. 276 19

We report in detail the ontogeny and the response of antioxidant enzymes to glucocorticoids in the rat small intestine. Pregnant rats in the treatment group received four injections of dexamethasone starting on days 18, 19, or 20 of gestation; fetuses were killed 2 days later. Control rats were injected with 0.9% saline solution. Postnatal rats reaching 14, 19, and 104 days of age received four injections of hydrocortisone and were killed 2 days later. Age-matched controls were injected with 0.9% saline solution. The activities of xanthine oxidase, superoxide dismutase, and catalase were measured in small intestines from fetal (20 and 21 days gestation), newborn, and older (aged 16, 21, and 106 days) rats. Xanthine oxidase rose with maturation; the major increase occurred on postnatal day 21. Catalase and superoxide dismutase rose minimally during intrauterine life. On day 16 postpartum, catalase and superoxide dismutase values were 160% and 60%, respectively, higher than at birth. Glucocorticoid administration stimulated maltase and sucrase activities, but had no effect on the antioxidant enzymes or xanthine oxidase.
J Pediatr 1987 Sep
PMID:Maturation of antioxidant enzymes in rat small intestine: lack of glucocorticoid stimulation. 362 18

The regulation of acylcoenzyme A:cholesterol acyltransferase (ACAT) activity by cholesterol was studied in an established enterocyte cell line. CaCo-2 cells were grown in culture to confluency and dome formation. They were characterized morphologically by light and transmission electron microscopy. During the culture period, ACAT activity remained stable while the activities of the brush border enzymes sucrase and alkaline phosphatase progressively increased with time and plateaued 12 days after plating. As determined by the rate of incorporation of oleic acid into the individual lipid classes, the rate of triglyceride synthesis was twice that of phospholipid and 15 times that of cholesteryl ester synthesis in these cells. Incubating CaCo-2 cells with cholesterol solubilized in taurocholate micelles resulted in a significant increase in ACAT activity (149 +/- 5 pmol/dish per 2 hr vs. 366 +/- 5, (P less than 0.001) without changing the rates of triglyceride or phospholipid synthesis. The stimulation of ACAT activity by micellar cholesterol was rapid, occurring within 5 min and reaching a maximal effect by 2 hr. The regulation of ACAT activity by cholesterol was directly dependent upon the concentration of cholesterol solubilized in the micelle and was independent of protein synthesis. Incubating CaCo-2 cells with micellar cholesterol did not increase the esterification of, nor did the cholesterol enter the pool of, newly synthesized or performed cholesterol within 2 hr. The micellar cholesterol that was taken up by the cells was esterified within 5 min after starting the incubation. Progesterone, a known ACAT inhibitor, significantly decreased the rate of esterification of intracellular micellar cholesterol proving that the cholesterol taken up by CaCo-2 cells was indeed entering the ACAT pool. Despite increasing amounts of unesterified cholesterol entering the cells via micelles, the percent of cholesterol that was esterified at any one time remained constant at 1%. The results suggest that ACAT activity in CaCo-2 cells is stimulated by cholesterol delivered to the cells by way of taurocholate micelles. The rapid entry of this sterol into the ACAT substrate pool suggests that ACAT activity in CaCo-2 cells is regulated by the expansion of the cholesterol substrate pool that is being utilized by an unsaturated ACAT enzyme.
J Lipid Res 1987 Sep
PMID:Regulation of cholesterol esterification by micellar cholesterol in CaCo-2 cells. 365 59

Castanospermine (1,6,7,8-tetrahydroxyoctahydroindolizine) is a potent time-dependent inhibitor of the sucrase-isomaltase complex purified from rat small intestine, in vitro. First-order kinetics for the inactivation of sucrase and isomaltase by castanospermine were observed. Protection studies showed that castanospermine competes for the glucosyl subsite with the substrates of sucrase and isomaltase. The second-order rate constants (k1) for the association reaction between castanospermine and the protein complex were calculated to be 6.5 X 10(3) and 0.3 X 10(3) M-1 s-1 for sucrase and isomaltase, respectively. Only barely detectable reactivation of the inhibited isomaltase was detectable over 24 h, whereas about 30% reactivation of the inhibited sucrase was observed in 24 h (k2 = 3.6 X 10(-6) s-1). These results suggest that castanospermine functions as a transition-state analog that binds extremely tightly to sucrase and isomaltase.
Arch Biochem Biophys 1987 Sep
PMID:Time-dependent inhibition of sucrase and isomaltase from rat small intestine by castanospermine. 366 35

The incidence, distribution, size, and histopathology of small and large bowel tumors induced by parenteral administration of 1,2-dimethylhydrazine were examined in rats given 1% or 2% sodium butyrate dissolved in drinking water. Although previous in vitro reports on colon cancer cell lines have suggested that sodium butyrate might have a role to play as a chemotherapeutic "differentiating agent," the results of this in vivo study indicate that sodium butyrate treatment enhanced the development of colonic neoplasia and was associated with increased fecal butyric acid concentrations. In contrast, no changes were seen in the incidence of small bowel tumors, luminal butyric acid concentrations, mucosal morphology, or brush-border enzyme activities (i.e., sucrase, alkaline phosphatase). This study suggests that dietary butyrate has an important, possibly indirect, regulatory role in carcinogenesis associated with an experimental animal model of colonic neoplasia.
Gastroenterology 1986 Sep
PMID:Effects of differing concentrations of sodium butyrate on 1,2-dimethylhydrazine-induced rat intestinal neoplasia. 373 64

Human serum contains lectins which inhibit the uptake of mannose- and N-acetylglucosamine-terminated glycoproteins by isolated rat hepatic sinusoidal cells. In these experiments, calcium-dependent and calcium-independent human serum mannose-binding proteins have been isolated by affinity chromatography using mannan linked to four different supports. In electroblots both calcium-dependent and -independent serum mannose-binding proteins bound radioiodinated mannan and invertase in the presence of calcium ions, but the binding of calcium-dependent serum mannose-binding proteins was abolished by EDTA. Chicken antibodies were raised against serum mannose-binding proteins and an ELISA was developed. The principal calcium-independent serum mannose-binding protein is mannose-specific IgG as judged by immunodiffusion and electroblotting with anti-human IgG antibodies. The calcium-dependent serum mannose-binding protein is probably the secreted form of an intracellular hepatocyte mannose-binding protein since: antibodies raised against the 30 kDa subunit of the calcium-dependent serum mannose-binding protein also bound 30 kDa subunits of whole liver homogenate and purified human liver mannose-binding protein; antibodies to the human liver mannose-binding protein bound to the 30 kDa subunit of the calcium-dependent serum mannose-binding protein; and the binding specificities of the calcium-dependent serum mannose-binding protein for N-acetylglucosamine and fucose as well as mannose, and its recognition of the core region of an oligosaccharide rather than only the peripheral sugars, were identical to those reported for the hepatocyte mannose-binding protein. The physiological ligands of these serum mannose-binding proteins are unknown but they could bind noxious glycoproteins which enter the circulation prior to their removal by the sinusoidal mannose receptor.
Biochim Biophys Acta 1986 Sep 04
PMID:Mannose-binding proteins in human serum: identification of mannose-specific immunoglobulins and a calcium-dependent lectin, of broader carbohydrate specificity, secreted by hepatocytes. 374 82

The yeast genome contains a dispersed family of invertase structural genes (SUC1-SUC5, SUC7). Five of these genes are located very close to telomeres and are flanked by large regions of homologous sequence; recombination between telomeres could account for the dispersal of these SUC genes to different chromosomes. The SUC2 locus, in contrast, is not near a telomere and does not share large regions of flanking homology with the other loci. We examine here the relationship between SUC2 and one of the telomeric genes, SUC7. Sequence comparison revealed homology extending from about position -624 to +1791, which is close to the end of the mRNA. The 5' noncoding sequence includes two highly conserved regions: the region between -140 and +1, which contains the TATA box and presumably other promoter elements, and a second region extending from -508 to -400, which corresponds to the upstream regulatory region.
Nucleic Acids Res 1985 Sep 11
PMID:Comparison of two yeast invertase genes: conservation of the upstream regulatory region. 390 Sep 28

Intestinal lactase activity is maintained at high levels in suckling rats during the first 2 wk after birth. When 12-day-old rat pups were either mother fed (MF) or artificially reared (AR) with natural rat milk or several artificial formulas, the small intestines had gained similar weight in all animal groups by 16 days except in AR rats fed a chemically defined formula. In the ileum, villus length was similar in MF and AR rats, but crypt depth was significantly higher in all groups of AR rats. Ileal absorptive cells in both MF and AR rats showed immature characteristics, including supranuclear vacuoles, apical tubular systems, and pinocytotic vesicles. Jejunal lactase specific activity and total intestinal lactase activity were significantly higher in AR rats fed rat milk than MF rats at 16 days. Ileal lactase specific activity was similar in these two animal groups. In contrast, AR rats fed artificial formulas supplemented with either glucose or lactose as the sole carbohydrate source exhibited significantly lower ileal lactase specific activity and total intestinal lactase activity than MF rats. Intestinal sucrase activity was prematurely elevated in all AR rats, even when fed natural rat milk. Addition of prolactin (3.3 micrograms/ml) to an artificial formula did not prevent the premature decrease in intestinal lactase specific and total activities in AR rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Pediatr Res 1985 Sep
PMID:Rat milk maintains intestinal lactase activity in rat pups whereas artificial formulas do not. 393 Oct 42

The intracellular localization of invertase endocytosed by rat liver was investigated by analytical centrifugation in sucrose and Percoll gradients of mitochondrial fractions originating from rats killed 15 h after injection. After isopycnic centrifugation in a sucrose gradient, invertase is located in higher density zones than acid hydrolases. The difference between the distribution of invertase and that of acid hydrolases increases with the amount of invertase injected. When the invertase dose is sufficiently high, a change of lysosomal enzyme distribution is clearly visible. It consists in the shift of a proportion of these enzymes to higher density regions where invertase is located. The proportion of hydrolase activity affected by invertase is different for each enzyme measured; it is the least pronounced for acid phosphatase, and most for acid deoxyribonuclease and arylsulfatase. A pretreatment of the rat with Triton WR 1339 considerably decreases the equilibrium density of structures bearing invertase. Nevertheless invertase distribution is quite distinct from that of the bulk of lysosomal enzymes that are recovered in lower density zones of the gradient; on the other hand the invertase injection to rats treated with Triton WR 1339 causes a spreading of the acid hydrolase distribution towards higher density zones. The distribution of acid hydrolases and invertase in a Percoll gradient depends on the sucrose concentration of the solvent. It is shifted towards higher densities when the sucrose concentration increases. The phenomenon is more important for invertase. These results are best explained by supposing that invertase accumulates in a distinct population of lysosomes that can be individualized as a result of the density increase they are subjected to by the invertase they accumulate. It is proposed that these lysosomes mainly originate from non-parenchymal cells of the liver.
Eur J Biochem 1985 Sep 16
PMID:Effect on lysosomes of invertase endocytosed by rat-liver. 402 43

The subcellular localization of the enzyme invertase in Schizosaccharomyces pombe cells, both repressed and derepressed for synthesis of the enzyme, was studied. Most of the invertase was found to be located outside the plasma membrane and only a small percentage was found to be associated to membranes. A substantial portion of the external enzyme remained firmly bound to cell-wall material. All of the invertase recovered in soluble form from cellular extracts reacted with concanavalin A and with the lectin from Bandeiraea simplicifolia seeds, indicating the presence in the enzyme of a carbohydrate moiety which probably contains terminal mannosyl (or structurally related) and galactosyl residues. The possibility of the presence of two different forms of invertase in S. pombe was considered. An intracellular, soluble form of invertase, devoid of carbohydrate, similar to the small invertase of the budding yeast Saccharomyces cerevisiae, was not found in S. pombe. However, the Michaelis constant for sucrose of the enzyme present in repressed cells was smaller than that of the invertase synthesized under derepressing conditions, although this difference could also be the result of a different pattern of glycosylation of the invertase synthesized under different growth conditions.
Arch Microbiol 1985 Sep
PMID:Subcellular localization and glycoprotein nature of the invertase from the fission yeast Schizosaccharomyces pombe. 406 84


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