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 RNA polymerase inhibitor, lomofungin has been used to determine the half life of specific synthetic capacities (invertase and alpha-glucosidase) as well as that for gross protein synthesis. In both cases the studies conclude that cognate messenger RNAs decay with a half life of approximately 20 minutes. This antibiotic has been used to determine the half life of allophanate hydrolase specific synthetic capacity. We find that it decays with a half life of about three minutes; a value that agrees with the decay rates of allophanate hydrolase synthetic capacity following removal of inducer. These observations argue that mRNA may be metabolized by two separate routes in Saccharomyces.
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PMID:Lomofungin inhibition of allophanate hydrolase synthesis in Saccharomyces cerevisiae. 110 15

A sucrose-inducible alpha-glucosidase activity that hydrolyzes sucrose in Candida albicans has been demonstrated previously. The enzyme is assayable in whole cells and was inhibited by both sucrose and maltose. A C. albicans gene (CASUC1) that affects sucrose utilization and alpha-glucosidase activity was cloned by expression in a Saccharomyces cerevisiae suc2 mutant (2102) devoid of invertase genes. CASUC1 enabled the S. cerevisiae mutant to utilize both sucrose and maltose. DNA sequence analysis revealed that CASUC1 encodes a putative zinc finger-containing protein with 28% identity to a maltose-regulatory gene (MAL63) of S. cerevisiae. The gene products of CASUC1 and MAL63 are approximately the same size (501 and 470 amino acids, respectively), and each contains a single zinc finger located at the N terminus. The zinc fingers of CASUC1 and MAL63 comprise six conserved cysteines (C6 zinc finger) and are of the general form Cys-Xaa2-Cys-Xaa6-Cys-Xaavariable-Cys-Xaa2-Cys-+ ++Xaa6-Cys (where Xaan indicates a stretch of the indicated number of any amino acids). Both contain five amino acids in the variable region. CASUC1 also complemented the maltose utilization defect of an S. cerevisiae mutant (TCY-137) containing a defined mutation in a maltose-regulatory gene. The sucrose utilization defect of type II Candida stellatoidea, a sucrase-negative mutant of C. albicans, was corrected by CASUC1. Determinations of alpha-glucosidase activity in whole cells revealed that activity was restored in transformants cultivated on either sucrose or maltose. To our knowledge, this is the first zinc finger-encoding gene, as well as the first putative regulatory gene, to be identified in C. albicans.
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PMID:A zinc finger protein from Candida albicans is involved in sucrose utilization. 172 10

Gastric intubation was adopted to examine the effect of continuous nutrient supply on digestive development of the pig during the immediate post-weaning period. The 14 d-weaned animals were slaughtered at 3, 5 and 7 d post-weaning (3W, 5W and 7W respectively) and the suckled animals were slaughtered at 14 and 22 d of age (14SR and 22SR respectively). The weight of the pancreas (g/kg bodyweight) was significantly greater (P less than 0.05) in the 5W and 7W groups, as was the weight of large intestine (g/kg) in all weaned groups (P less than 0.01) compared with sow-reared pigs. The stomach weight (g/kg) tended to be greater in the weaned groups. Weaning, in conjunction with a continuous nutrient supply, did not significantly alter the time-related changes in the weight of the small intestine (SI) or the SI mucosa, although both variables tended to be lowest in the 3W group. However, there was a 20% reduction in the protein content of the mucosa within the first 3 d post-weaning (P less than 0.01) which persisted during the 7 d experimental period. Lactase, (beta-galactosidase; EC 3.2.1.23) activity (mumol/g protein and mol/d) of the 7W group was reduced to approximately 40% of the 22SR value. Hence, continuous nutrient supply may have delayed, but did not prevent, the loss of lactase activity at weaning. The activity of sucrase (sucrose-alpha-glucosidase; EC 3.2.1.48) was significantly higher in 22SR compared with 14SR animals. Sucrase activity in weaned pigs was intermediate to the values for sow-reared pigs whereas maltase (alpha-glucosidase; EC 3.2.1.20) and glucoamylase (glucan 1,4-alpha-glucosidase; EC 3.2.1.3) were significantly increased in relation to their sow-reared counterparts. Continuous nutrient supply did not prevent the reduction in villous height and the crypt hypertrophy associated with weaning. The results of the present study suggest that there may be some degree of interaction between nutrient intake and gut development during the immediate post-weaning period but that there is also a component of the adaptive response which is independent of nutrient intake. They confirm the rapid substrate induction of the brush-border glucoamylases and indicate the importance of considering total as well as specific enzyme activity for satisfactory interpretation of changes in digestive function.
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PMID:Digestive development of the early-weaned pig. 1. Effect of continuous nutrient supply on the development of the digestive tract and on changes in digestive enzyme activity during the first week post-weaning. 190 70

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

Candida stellatoidea is classically distinguished from C. albicans by the ability of the latter species to assimilate sucrose. We show here that sucrose-positive revertants of C. stellatoidea type II are readily isolated and that C. stellatoidea type II strains probably resulted from a mutation in the sucrase gene of C. albicans. The revertants were not laboratory contaminants, as determined by restriction fragment length polymorphism analysis and retention of an auxotrophic marker. The reversion of three tested strains was accompanied by 16 to 110-fold increases in expression of a sucrase/alpha-glucosidase but not an invertase, with a Km for sucrose of about 1 mM. The enzyme activity was assayable in intact cells. The drastically increased expression of such an enzyme would allow extracellular sucrose hydrolysis and assimilation of the monosaccharide products.
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PMID:Evidence that Candida stellatoidea type II is a mutant of Candida albicans that does not express sucrose-inhibitable alpha-glucosidase. 197 85

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

A histochemical study of the time course of the appearance and location of lactase and alpha-glucosidase (used to detect sucrase and maltase) activities was carried out on control and rotavirus-infected mice from 7 to 14 days old. The overall pattern of enzyme activity was in agreement with previous quantitative studies on the activities of these enzymes. No evidence was obtained to support the idea that lactase deficiency was the result of repopulation of villi (denuded of lactase-producing villus cells) with immature lactase-negative cells. Low lactase activity was more likely to reflect profound changes in metabolically crippled cells, and recovery of lactase activity with recovery of normal metabolic functions. The location of enzyme activity to brush border regions rather than the cytoplasm of villus enterocytes enhances the significance of previous quantitative studies on these enzymes. The timing and duration of diminished lactase activities were such that they were unlikely to cause the induction or perpetuation of diarrhea in murine rotavirus diarrhea. The appearance in infected animals of alpha-glucosidase 3 days earlier than normal indicates that, in addition to reversible changes seen with lactase, developmental changes were accelerated that affected both crypt and villus cells.
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PMID:Disaccharidase activities in small intestine of rotavirus-infected suckling mice: a histochemical study. 212 44

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

1. Sugar-containing diets chosen not to affect intestinal structure or enterocyte turnover have been fed to mice previously maintained on a low carbohydrate diet in order to determine their ability to induce disaccharidase enzymes in the small intestine. 2. Glucose-, fructose- and 3-O-methyl-glucose-containing diets increased sucrase and maltase but not lactase activities in mouse jejunal homogenates. These effects were either absent or negligible in more distal regions of the small intestine. 3. Placing mice on glucose-, fructose- or 3-O-methyl-glucose-containing diets was further shown, by quantitative cytochemistry, to cause a 1.6-, 2.6- and 3.2-fold increase in the initial rate at which alpha-glucosidase activity (sucrase + maltase) appeared in the brush-border membrane of developing enterocytes. 4. The time during which alpha-glucosidase activity increased in enterocyte brush-border membranes fell from 30 h for low carbohydrate fed mice to 21, 19 and 17 h in mice fed glucose, fructose and 3-O-methyl-glucose respectively. Change of diet had no effect on the kinetics of lactase expression by developing enterocytes. 5. Maximal alpha-glucosidase activity detected in enterocyte brush-border membranes is equal to RT, where R is the initial rate of enzyme appearance and T is the time during which this rate operates. The ability of sugars to increase R selectively, but only at the expense of T, defines unexpected limits to the capacity of enterocytes to adapt to changes in luminal nutrition. 6. The above results are discussed in relation to other aspects of enterocyte differentiation recently subjected to quantitative analysis. The need to standardize other aspects of intestinal physiology and redefine the energy content of diets containing non-metabolizable substrates in this type of work is also emphasized.
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PMID:Sugar-dependent selective induction of mouse jejunal disaccharidase activities. 251 26

Disaccharidases of oral bacteria, especially alpha-glucosidase and beta-fructofuranosidase, are considered to play an important role in the induction of dental caries. Upon the examination of disaccharidases from several strains of saccharolytic oral bacteria, we found all of those bacteria to be capable of hydrolyzing the glycosidic linkage of sucrose. One species of bacteria, Rothia dentocariosa, was found to contain a single disaccharidase, alpha-glucosidase. This enzyme was partially purified by ammonium sulfate precipitation, gel filtration and ion-exchange column chromatography. The optimum pH and temperature for the enzyme activity was found to be 6.8-7.0 and 40 degrees C, respectively. The enzyme activity was strongly inhibited by Ag+, Hg2+, Cu2+, Fe2+ and Tris (Hydroxymethyl) aminomethane.
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PMID:Partial purification and characterization of alpha-glucosidase from Rothia dentocariosa. 263 58


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