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)

Different ligands with high molecular masses are immobilized on compact, porous separation units and used for affinity chromatography. In subsequent experiments different enzymes are immobilized and used for converting substrates with low and high molecular masses. Disk or tube with immobilized concanavalin A (ConA) are used as model systems for lectin affinity chromatography. The enzyme glucose oxidase is used as a standard protein to test the ConA units. Subsequently glycoproteins from plasma membranes of rat liver are separated, using units with immobilized ConA. The enzyme dipeptidyl peptidase i.v., which is used as a model protein in the experiments, is enriched about 40-fold in a single step, with a yield of over 90%. The results are only slightly better than those obtained with ConA when it is immobilized on bulk supports. The important improvement lies in the reduction of separation time to only 1 h. Experiments concerning the isolation of monoclonal antibodies against clotting factor VIII (FVIII) are carried out on disks, combining anion-exchange chromatography and protein A affinity chromatography as a model for multidimensional chromatography. Both IgG (bound to the protein A disk) and accompanying proteins (bound to the anion-exchange disk) from mouse ascites fluid are retarded and eluted separately. With the immobilized enzymes invertase and glucose oxidase (GOX) the corresponding substrates with low molecular masses, saccharose and glucose, are converted. It is shown that the amount of immobilized enzyme and the concentration of the substrate are responsible for the extent of the conversion, whereas the flow-rates used in the experiments have no effect at all. The influence of immobilization chemistry was investigated with GOX. Indirect immobilization with ConA as spacer proved to be the best alternative. With trypsin, immobilized on a disk, substrates with high molecular masses are digested in flow-through. For optimal digestion the proteins have to be denatured in the buffer for sodium dodecyl sulfate-polyacrlyamide gel electrophoresis prior to application. In contrast to the conversion of substrates with low molecular masses, flow-rates play an important part in conversion of substrates with high molecular masses. With lower flow-rates a higher degree of digestion is achieved.
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PMID:Use of compact, porous units with immobilized ligands with high molecular masses in affinity chromatography and enzymatic conversion of substrates with high and low molecular masses. 960 27

The extent of N-glycosylation of yeast external invertase at each of the 14 potential sites was determined by the combination of proteolytic digestions and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF-MS). The average molecular mass of the intact external invertase was determined as 97 kDa by MALDI/TOF-MS. The intact protein was digested with trypsin, Lys-C and Asp-N, followed by high-performance liquid chromatographic separation. The proteolytic digests were analyzed by MALDI/MS screening for the glycopeptides. The glycopeptides were then treated with peptide:N-glycosidase F (PNGase F) and/or endo-beta-N-acetylglucosaminidase (Endo H) and the molecular mass of the deglycosylated peptide was determined by MALDI/MS and matched with the peptide predicted by a computer program. The sequences of some peptides or deglycosylated peptides were identified by the MALDI post-source decay technique. The size of the oligosaccharide, the degree of glycosylation and the distribution of the oligosaccharides at each individual potential glycosylation site were characterized. This information goes for beyond previously published data and sometimes differs from them. During this study, the amino acid sequence originally derived from the DNA sequence of the gene coding for invertase was also verified and it was found that this protein when expressed from SUC2 gene might be created as more than one sequence which differ by a few amino acid substitutions (Asn58<-->Thr, Asn65-->His and Val412<-->Ala).
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PMID:Determination of N-linked glycosylation of yeast external invertase by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. 1022 60

Modulation of gut function is important in an ecological and evolutionary context because it likely determines what food items an animal can and cannot eat. We examined how diet affects activity of digestive enzymes in an omnivorous bird, the pine warbler (Dendroica pinus). Pine warblers were fed insect-based, fruit-based, and seed-based diets for approximately 54 d. We then measured activity of amylase, maltase, sucrase, aminopeptidase-N, trypsin, chymotrypsin, carboxypeptidase A, carboxypeptidase B, pancreatic lipase, and carboxyl ester lipase. We predicted that carbohydrase activities would be highest in birds fed the diet highest in carbohydrates (fruit based), protease activities would be highest in those fed the diet highest in protein (insect based), and lipase activities would be highest in those fed the diets highest in lipid (insect based and seed based). Also, we predicted that pine warblers would exhibit greater dietary modulation of enzyme activity than reported for a less omnivorous congener, the yellow-rumped warbler (Dendroica coronata). All predictions were upheld, supporting the hypothesis that pine warblers modulate the activity of digestive enzymes in proportion to demand from substrates in the diet.
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PMID:An experimental test of dietary enzyme modulation in pine warblers Dendroica pinus. 1052 25

Alkyl-substituted hydroxybenzenes (AHBs), which are auto-inducers of microbial dormancy (d1 factors), were found to stabilize the structure of protein macromolecules and modify the catalytic activity of enzymes. In vitro experiments showed that C6-AHB at concentrations from 10(-4) to 10(-2) M, at which it occurs in the medium as a true solution and a micellar colloid, respectively, nonspecifically inhibited the activity of chymotrypsin, RNase, invertase, and glucose oxidase. C6-AHB-induced conformational alterations in protein macromolecules were due to the formation of complexes, as evidenced by differences in the fluorescence spectra of individual RNase and C6-AHB and their mixtures and in the surface tension isotherms of C6-AHB and trypsin solutions. Data on the involvement of dormancy auto-inducers in the post-translational modification of enzymes and their inhibition will provide further insight into the mechanisms of development and maintenance of dormant microbial forms.
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PMID:[The function of anabiosis autoinductors in microorganisms under blockade of metabolism]. 1077 21

This paper describes the cloning and functional analysis of chicory (Cichorium intybus L.) fructan 1-exohydrolase I cDNA (1-FEH I). To our knowledge it is the first plant FEH cloned. Full-length cDNA was obtained by a combination of RT-PCR, 5' and 3' RACE using primers based on N-terminal and conserved amino acid sequences. Electrophoretically purified 1-FEH I enzyme was further analyzed by in-gel trypsin digestion followed by matrix-assisted laser desorption ionization and electrospray time-of-flight tandem mass spectrometry. Functionality of the cDNA was demonstrated by heterologous expression in potato tubers. 1-FEH I takes a new, distinct position in the phylogenetic tree of plant glycosyl hydrolases being more homologous to cell-wall invertases (44-53%) than to vacuolar invertases (38-41%) and fructosyl transferases (33-38%). The 1-FEH I enzyme could not be purified from the apoplastic fluid at significantly higher levels than can be explained by cellular leakage. These and other data suggest a vacuolar localization for 1-FEH I. Also, the pI of the enzyme (6.5) is lower than expected from a typical cell-wall invertase. Unlike plant fructosyl transferases that are believed to have evolved from a vacuolar invertase, 1-FEH I might have evolved from a cell-wall invertase-like ancestor gene that later obtained a vacuolar targeting signal. 1-FEH I mRNA quantities increase in the roots throughout autumn, and especially when roots are stored at low temperature.
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PMID:Cloning and functional analysis of chicory root fructan1-exohydrolase I (1-FEH I): a vacuolar enzyme derivedfrom a cell-wall invertase ancestor? Mass fingerprint of the 1-FEH I enzyme. 1111 26

Six decades of studies have speculated that digestive capacity might limit avian growth rate or that developmental changes in the gut might determine developmental changes in digestive efficiency. However, there are no studies on digestive enzymes during avian development, except for studies on mainly domestic birds that exhibit the precocial mode of development. We studied alimentary organ masses, intestinal enzyme activities (sucrase, maltase, isomaltase, aminopeptidase-N), and pancreatic enzyme activities (amylase, trypsin, chymotrypsin) during development of a wild passerine bird exhibiting the altricial mode of development. Wild nestling house sparrows were studied immediately after removal from the nest (days 0, 3, 6 of age; day 0=hatch), whereas captives were raised in the laboratory beginning day 3 on a formulated casein/starch-based diet until fledging age (after day 12). Digestive biochemistry was dynamic. Tissue-specific activities of some digestive enzymes continued to increase through fledging, by >10 times in some cases (e.g., sucrase and maltase in midintestine). Total pancreatic amylase activity increased 100 times between hatch and day 12 through a combination of increases in tissue-specific activity and pancreas mass. House sparrows differ from poultry, in whom after about 2 wk of age the specific activity of intestinal and pancreatic digestive enzymes is generally constant or declines during development. The data on intestinal and pancreatic enzymes help explain why digestive efficiency of nestling house sparrows improves with age, and the data seem consistent with the idea that digestive capacity might limit feeding rate and hence growth rate.
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PMID:Developmental changes in digestive physiology of nestling house sparrows, Passer domesticus. 1151 62

Smaller guts and slow initial mass gains at stopover sites have led to the idea that digestive physiology limits refueling rates in migrating birds. We tested the digestive-limitation hypothesis in yellow-rumped warblers using food restriction to simulate infrequent feeding during migration, which may cause a reduction in alimentary tract mass. Restricted birds had small intestine, pancreas, and liver masses 18%-22% lower than ad lib.-fed controls. Total activities of sucrase, maltase, aminopeptidase, and amylase were significantly lower in restricted birds, while those of trypsin and chymotrypsin were not. Only aminopeptidase mass-specific activity was significantly lower in restricted birds. Previously restricted birds were able to feed and digest at a high rate immediately following return to ad lib. feeding. Digestive efficiency did not differ between groups. These results suggest that before migration yellow-rumped warblers have some spare digestive capacity to compensate for declines in their digestive organ masses during migration.
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PMID:Digestive response to restricted feeding in migratory yellow-rumped warblers. 1217 34

Maturation of the fetal gastrointestinal tract (GIT) is influenced by both luminal stimuli (e.g. swallowed fluid) and hormonal factors (e.g. endogenous cortisol release). The aims of the present study were 1) to investigate GIT growth and maturation during the last 20% of gestation in pigs (term = 114 +/- 2 d), and 2) to investigate the effect of esophageal ligation, to prevent fetal swallowing, at 80% to 91% gestation. In normal fetuses, marked increases occurred during late gestation in body weight (+95%), relative intestinal weight (+79%, g kg(-1) body weight), activity of some digestive enzymes (1.5- to 10-fold), and absorption of glucose and intact proteins (3- to 6-fold). Fetuses with ligated esophagi had lowered body weight (-20%), reduced intestinal weight (-43%), aminopeptidase A activity (-24%), and glucose absorption (-27%), while lactase, sucrase, and dipeptidylpeptidase IV activities were increased (+40-50%), compared with sham-operated fetuses (all p < 0.05). Other parameters of GIT function remained unchanged by esophageal obstruction (absorption of amino acids and immunoglobulin, activity of chymosin, amylase, trypsin, chymotrypsin, maltase, aminopeptidase N -- all expressed per gram GIT tissue). Ligated fetuses had elevated cortisol levels, which is known to stimulate fetal GIT maturation. We conclude that the rapid development of GIT function in late gestation is diminished by esophageal obstruction, mainly due to slower GIT growth and not inhibition of normal functional development of enterocytes.
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PMID:Prenatal development of gastrointestinal function in the pig and the effects of fetal esophageal obstruction. 1219 78

To simulate the effects of nutritionally adequate and inadequate vegetarian diets, rats were fed, for 28 days, an isonitrogenous, isocaloric, amino acid unbalanced cereal diet (CD) deficient in lysine and tryptophan or a balanced cereal-legume diet (CLD). The impact of these diets on enzymes responsible for digestion of proteins and carbohydrates were measured. Neither experimental diet significantly affected the animal's final weight or feed consumption in comparison with controls fed a standard mixed diet from plant and animal sources. However, during the first three weeks, the weight gain of rats fed the CD was significantly lower (p < 0.01; p < 0.05) than that of the controls. CD fed rats also had a higher feed efficiency ratio (p < 0.05), demonstrating increased feed consumption per unit of body weight. They also had decreased pancreatic alpha-amylase activity (p < 0.05), serum phytolytic and zoolytic alpha-amylase activity (p < 0.05) and serum protein level (p < 0.05) than the controls. Activity of pancreatic trypsin and intestinal enzymes (sucrase, maltase, aminopeptidase N) were the same as in the controls. In rats fed CLD, growth, food consumption, and enzyme activities did not change, however serum protein and glucose levels were higher (p < 0.025; p < 0.005) than in the controls. It is hypothesized that decrease in alpha-amylase activity was mostly related to the tryptophan deficiency in the CD because this enzyme contains the highest amount of tryptophan units among all tested enzymes.
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PMID:Pancreatic and intestinal enzyme activities in rats in response to balanced and unbalanced plant diets. 1260 33

Oligomeric actin-interacting protein 2 (Aip2p) [Nat. Struct. Biol. 2 (1995) 28]/D-lactate dehydrogenase protein 2 (Dld2p) [Yeast 15 (1999) 1377, Biochem. Biophys. Res. Commun. 295 (2002) 910] exhibits the unique grapple-like structure with an ATP-dependent opening [Biochem. Biophys. Res. Commun. 320 (2004) 1271], which is required for the F-actin conformation modifying activity in vitro and in vivo [Biochem. Biophys. Res. Commun. 319 (2004) 78]. To further investigate the molecular nature of oligomeric Aip2p/Dld2p, the substrate specificity of its binding and protein conformation modifying activity was examined. In the presence of 1mM ATP or AMP-PNP, oligomeric Aip2p/Dld2p bound to all substrates so far examined, and modified the conformation of actin, DNase I, the mature form of invertase, prepro-alpha-factor, pro-alpha-factor, and mitochondrial superoxide dismutase, as determined by the trypsin susceptibility assay. Of note, the activity could modify even the conformation of pathogenic highly aggregated polypeptides, such as recombinant prion protein in beta-sheet form, alpha-synuclein, and amyloid beta (1-42) in the presence of ATP. The in vivo protein conformation modifying activity, however, depends on the growth stage; the most significant substrate modification activity was observed in yeast cells at the log phase, suggesting the presence of a cofactor/s in yeast cells, where F-actin is supposed to be a major target in vivo. These data further support our previous notion that the oligomeric Aip2p/Dld2p may belong to an unusual class of molecular chaperones [Biochem. Biophys. Res. Commun. 320 (2004) 1271], which can target both properly folded and misfolded proteins in an ATP-dependent manner in vitro.
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PMID:Oligomeric Aip2p/Dld2p modifies the protein conformation of both properly folded and misfolded substrates in vitro. 1535 42


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