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)

Extracellular glucoamylase activity was increased by a gene, which is present in super-secretor, but absent in low-secretor, strains of the yeast Saccharomyces cerevisiae. Genetic data indicated that this super-secretor gene is linked to the STA3 structural gene for glucoamylase. This gene appears to act specifically since it increased the secretion of glucoamylase but not of other secreted enzymes like acid phosphatase and invertase.
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PMID:A genetic analysis of an alpha-amylase super-secretor in yeast; implications for the regulatory pathway. 193 24

Glycogen can be degraded in mammalian tissues by one of three isozymes of glycogen phosphorylase, termed muscle (M), liver (L) and brain (B) after the tissues in which they are preferentially expressed in adult animals, or by members of the family of alpha-glucosidases. In the current study, we have examined the developmental expression of these enzymes and their respective mRNAs in rabbit tissues, with particular emphasis on the developing lung, a tissue in which glycogen serves as an important source of carbon for surfactant phospholipid biosynthesis. Native gel activity assays and RNA blot hybridization analysis revealed that the B isoform of glycogen phosphorylase predominates in fetal and adult lung tissues, accompanied by a low level of expression of the M isoform. Total B and M phosphorylase activities increased during fetal lung development, with a peak at day 28 of gestation, then decreased to the adult level at term. This peak in activity coincided with the peak period of glycogen degradation in developing lung. While the increase in M isozyme activity was correlated with an increase in the level of its mRNA, B isoform mRNA showed no significant alteration during development, suggesting that the increase in B isoform activity is determined by a posttranscriptional mechanism. Analysis of phosphorylase mRNA levels in developing liver, skeletal muscle, brain and heart revealed a diverse expression pattern. The L isozyme mRNA was predominant at all time points in liver, the M isozyme was predominant at all time points in muscle, the B isozyme was predominant at all time points in brain, and heart contained a mixture of B and M mRNA in roughly equal ratios at all time points. Thus, our studies of phosphorylase mRNA in the rabbit provide no evidence for general predominance of the B isozyme in fetal tissues, or for isozyme 'switching' from the B to the L or M forms during development, as has been suggested by others. In addition to the increase in phosphorylase activity, acid, but not neutral alpha-glucosidase activity was found to increase significantly during fetal lung development, again with a peak at day 28 of gestation. Interestingly, RNA blot hybridization analysis with a probe for lysosomal alpha-glucosidase revealed no change in the level of expression of its 4 kb transcript in developing lung. Instead, we observed induction of a structurally related mRNA of 7.4 kb that peaked at day 28 of gestation. Hybridization with a sucrase/isomaltase-specific oligonucleotide excluded the possibility that the 7.4 kb transcript encodes this protein.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Developmental expression of glycogenolytic enzymes in rabbit tissues: possible relationship to fetal lung maturation. 195 55

Gastric intubation was adopted as a means of comparing the effect of two feeding levels, continuous nutrient supply (C) and restricted nutrient supply (R), on the digestive development of pigs weaned at 14 d of age, during the first 5 d post-weaning. The absolute weights of the stomach and the pancreas were significantly greater (P less than 0.001) in C compared with R pigs. The effect was not significant for pancreas weight when expressed per kg body-weight but was significant (P less than 0.05) for stomach weight. The weights of the small intestine (SI), SI mucosa and total mucosal protein were significantly higher (P less than 0.001) in C pigs but protein content per g mucosa was similar in the C and R groups. There was no significant effect of treatment on the activity of lactase (beta-glucosidase; EC 3.2.1.23) or sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) irrespective of the basis of comparison used. The specific activity (mumol/min per g protein) of maltase (alpha-glucosidase; EC 3.2.1.20) and of glucoamylase (glucan-1,4-alpha-glucosidase; EC 3.2.1.3) were similar in C and R groups but activities of maltase (mumol/g mucosa) (P less than 0.05), and maltase and glucoamylase (mol/d) (P less than 0.01) were significantly higher in C pigs. Villous height and crypt depth were significantly greater in C pigs (P less than 0.001 and P less than 0.05 respectively). Enteroglucagon was significantly (P less than 0.05) higher in C compared with R pigs. Xylose absorption and the digestibility of energy were not affected by treatment. Digestibility of dry matter, organic matter, crude protein (nitrogen x 6.25) and carbohydrate were significantly higher (P less than 0.001, P less than 0.01, P less than 0.05 and P less than 0.001 respectively) in R pigs compared with C pigs but the differences were small, ranging from 1.3 to 2.5%. These results demonstrate that (1) nutrient intake in the weaned pig affects the anatomy, morphology and function of the gut, (2) there is considerable 'spare capacity' for digestion of cereal-based diets even in pigs weaned at 14 d of age, (3) measurements in vitro of digestive function are of limited value unless supported by information in vivo on absorption/digestibility.
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PMID:Digestive development of the early-weaned pig. 2. Effect of level of food intake on digestive enzyme activity during the immediate post-weaning period. 204 2

Inhibition of intestinal alpha-glucohydrolase activity is one approach for reducing the glycemic response from dietary carbohydrate and may prove useful for the treatment of diabetes mellitus. In this article, we describe the pharmacological properties of a time-dependent intestinal alpha-glucohydrolase inhibitor, MDL 73945. When preincubated 2 h with a rat intestinal mucosa preparation before substrate addition, MDL 73945 was a potent inhibitor of sucrase, maltase, glucoamylase, and isomaltase activities (MDL 73945 concentrations required to cause a 50% decrease in enzyme activity, 2 x 10(-7), 1 x 10(-6), 5 x 10(-6), and 8 x 10(-6) M, respectively); without preincubation, it was 10- to 500-fold less potent. In rats, a single oral dose of MDL 73945 administered simultaneously with 2 g/kg body wt sucrose resulted in a dose-dependent reduction in the area under the 0- to 3-h glycemic response curve, which was significant at 1 (45% reduction) and 3 (65% reduction) mg/kg. When administered 1 h before sucrose, the compound was more potent, with 0.3 mg/kg MDL 73945 significantly reducing the glycemic response to sucrose by 62%. A reduction in the glycemic response to sucrose was accompanied by reduced insulin secretion. MDL 73945 was slightly less effective against a starch load, with 3 and 10 mg/kg MDL 73945 administered 0.5 h before starch reducing the glycemic response by 39 and 52%, respectively. MDL 73945 was more effective against a sucrose load in streptozocin-administered rats than in control rats and was as effective after 16 daily doses as after a single dose.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:New potent alpha-glucohydrolase inhibitor MDL 73945 with long duration of action in rats. 206 Jul 19

Brush border lactase, sucrase and glucoamylase activities were assessed in jejunal mucosal biopsy specimens from 34 children (median age 11 months; range 1.5-38) having protracted diarrhoea with failure to thrive and 8 well nourished children with normal jejunal mucosal histology (median age 10.2 months; range 2-37). All enzymes showed progressive decrease in activity which was directly in relation to increasing degree of mucosal injury (P less than 0.002). Lactase was significantly reduced even in patients with protracted diarrhoea and normal mucosa (P less than 0.05). Glucoamylase and sucrase were significantly reduced only in the presence of mucosal injury (P less than 0.01). Our data suggest that most children with protracted diarrhoea may not tolerate lactose containing feeds and may need lactose-free diets preferably based on starch. A small number of children with protracted diarrhoea, who have severe mucosal injury may not be able to handle even starch and may require diets based on short chain glucose polymers. The findings of this study, need to be corroborated with well-controlled metabolic balance studies.
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PMID:Intestinal glucoamylase & other disaccharidases in children with protracted diarrhoea. 211 15

Seven mutants of Saccharomyces cerevisiae deficient in production of extracellular glucoamylase have been analyzed. For each of the seven a monogenic pattern of inheriting the mutant phenotype has been observed. The mutations have been shown to map within five different genetic loci, three independent mutations affecting the STA2 locus and the other four residing in four formerly unidentified genes. As expected, the sta2 mutants recover the wild phenotype when transformed with a STA2-bearing multicopy plasmid. Such reversion has also been observed for the transformed stall mutant. Unlike the others, the sta16 mutant is unable to secrete heterologous alpha-amylase encoded by a plasmid-borne DNA fragment. All the mutants have a moderately reduced ability to secrete the invertase and acid phosphatase.
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PMID:[Mutational analysis of the starch utilization system in the yeast Saccharomyces cerevisiae]. 219 27

Three pseudo-aminosugars, validamine, valienamine and valiolamine, produced by Streptomyces hygroscopicus subsp. limoneus showed potent inhibitory action on rat small intestinal carbohydrase activities such as sucrase, maltase, glucoamylase, isomaltase and trehalase activities, but negligible action on lactase activity and pancreatic alpha-amylase activity. Where inhibition was seen, kinetic analysis showed fully competitive inhibition of the carbohydrase activities by all three inhibitors. Valiolamine has more potent carbohydrase inhibitory activity than validamine or valienamine, and the apparent Ki values of valiolamine for sucrase, maltase, glucoamylase, isomaltase and trehalase activities were 3.2 x 10(-7), 2.9 x 10(-6), 1.2 x 10(-6), 9.1 x 10(-7) and 4.9 x 10(-5) M, respectively, which are 10(-5) to 10(-3) times smaller than the apparent Km values.
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PMID:Inhibitory effect of validamine, valienamine and valiolamine on activities of carbohydrases in rat small intestinal brush border membranes. 226 98

Lentiginosine, a dihydroxyindolizidine alkaloid, was extracted from the leaves of Astragalus lentiginosus with hot methanol and was purified to homogeneity by ion-exchange, thin-layer, and radial chromatography. A second dihydroxyindolizidine, the 2-epimer of lentiginosine, was also purified to apparent homogeneity from these extracts. Gas chromatography of the two isomers (as the TMS derivatives) showed that they were better than 95% pure; lentiginosine eluted at 8.65 min and the 2-epimer at 9.00 min. Both compounds had a molecular ion in their mass spectra of 157, and the NMR spectra demonstrated that both were dihydroxyindolizidines differing in the configuration of the hydroxyl group at carbon 2. Lentiginosine was found to be a reasonably good inhibitor of the fungal alpha-glucosidase, amyloglucosidase (Ki = 1 x 10(-5) M), but it did not inhibit other alpha-glucosidases (i.e., sucrase, maltase, yeast alpha-glucosidase, glucosidase I) nor any other glycosidases. The 2-epimer had no activity against any of the glycosidases tested.
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PMID:Lentiginosine, a dihydroxyindolizidine alkaloid that inhibits amyloglucosidase. 233 69

The effect of chronic intragastric infusion of hypertonic mannitol on small intestinal mucosal structure and function was studied in adult rats. Animals were gavage-fed 20% mannitol (1300 mosm) at a dose of 5 ml/100 g body weight daily for seven days. Control animals were gavage-fed tap water on the same schedule. On day 8, the animals were anesthetized, the duodenum cannulated, and a test sugar (glucose, glucose polymer, lactose, sucrose, or maltose) was infused at a dose of 0.5 g/kg body weight in 2.5 ml distilled water over less than 1 min. Portal vein glucose was measured at 30-min intervals from 0 to 120 min. Mannitol treatment resulted in histologic and biochemical alterations (reduced lactase, sucrase, maltase) limited to the proximal small intestine compared to the control group. The absorption of glucose and glucose polymers was similar in mannitol-treated and control animals. In contrast, digestion and absorption of lactose, sucrose, and maltose was significantly diminished in mannitol-treated animals when compared to controls. No changes in permeability to polyethylene glycol 4000 or Na+-coupled glucose transport were observed in mannitol-treated animals compared to controls. These data suggest that when the intestinal mucosa is exposed to hyperosmolar loads that the digestive capacity for disaccharides is suppressed more than its glucose absorptive capacities. Furthermore, glucose oligomers may be more readily digested and absorbed than disaccharides, in this setting, due, in part, to the proximal injury and less pronounced proximal-distal gradient for glucoamylase than other brush-border carbohydrases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Proximal small intestinal mucosal injury. Maintenance of glucose and glucose polymer absorption, attenuation of disaccharide absorption. 249 65

Depending on the rats emotional background, unequal invertase and monoglyceride-lipase activity was found which did not correlate with the intensity of synthesis of these enzymes in the enterocytes but depended on the stability or mobility of the enzyme molecules in lipid membranes. The differences found in the amylase activity in the colon homogenates were, probably, connected with different intensity of pancreatic alpha-amylase restoration and own intestine gamma-amylase synthesis.
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PMID:[Emotional behavior and correlation of the processes of membrane and cavity digestion in rats]. 250 58


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