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)

Two cDNAs (Ib beta fruct2 and Ib beta fruct3) encoding vacuolar invertases were cloned from sweet potato leaves, expressed in Pichia pastoris, and the recombinant proteins were purified by ammonium sulfate fractionation and chromatography on Ni-NTA agarose. The deduced amino acid sequences encoded by the cDNAs contained characteristic conserved elements of vacuolar invertases, including the sequence R[G/A/P]xxxGVS[E/D/M]K[S/T/A/R], located in the prepeptide region, Wxxx[M/I/V]LxWQ, located around the starting site of the mature protein, and an intact beta-fructosidase motif. The pH optimum, the substrate specificity, and the apparent K(m) values for sucrose exhibited by the recombinant proteins were similar to those of vacuolar invertases purified from sweet potato leaves and cell suspensions, thus confirming that the proteins encoded by Ib beta fruct2 and Ib beta fruct3 are vacuolar invertases. Moreover, northern analysis revealed that the expression of the two genes was differentially regulated. With the exception of mature leaves and sprouting storage roots, Ib beta fruct2 mRNA is widely expressed among the tissues of the sweet potato and is more abundant in young sink tissues. By contrast, Ib beta fruct3 mRNA was only detected in shoots and in young and mature leaves. It appears, therefore, that these two vacuolar invertases play different physiological roles during the development of the sweet potato plant.
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PMID:Vacuolar invertases in sweet potato: molecular cloning, characterization, and analysis of gene expression. 1585 18

An endoinulinase produced by Chaetomium sp. C34 was purified to electrophoretic homogeneity, with recovery of 7.7% activity and purification factor of 30.8 fold by five steps including ammonium sulfate precipitation, DEAE-cellulose, Q-sepharose Fast Flow, Sephacryl S-200 and Pre-Packed Hydrophobic Column. Its subunit molecular weight was estimated to be about 66kD by SDS-PAGE. The optimum temperature and pH of the enzyme activity were 50 approximately 55 degrees C and 6.0 respectively. The K(m) and V(max) values for inulin were 0.199 mmol/L and 115 micromol/(mg x min) respectively. Cu2+ completely inhibited inulinase activity. An appreciable loss of activity was observed in presence of NBS, Mn2+, Zn2+, Fe2+ and EDTA. A ratio of inulinase activity to invertase activity (I/S) of 20 was found in purified inulinase. The endoinulinase hydrolyzed inulin and liberated inulooligosaccharides. But it lacked activity toward melezitose or raffinose.
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PMID:[Purification and properties of endoinulinase from Chaetomium sp]. 1611 Sep 61

Three Bo beta fruct cDNAs encoding acid invertases were cloned from shoots of the green bamboo Bambusa oldhamii. On the basis of the amino acid sequences of their products and phylogenetic analyses, Bo beta fruct1 and Bo beta fruct2 were determined to encode cell wall invertases, whereas Bo beta fruct3encodes a vacuolar invertase. The recombinant proteins encoded by Bo beta fruct2 and Bo beta fruct3 were produced in Pichia pastoris and purified to near homogeneity using ammonium sulfate fractionation and immobilized metal affinity chromatography. The pH optima, pI values, and substrate specificities of the isolated enzymes were consistent with those of plant cell wall or vacuolar invertases. The growth-dependent expression of Bo beta fruct1 and Bo beta fruct2 in the base regions of shoots underscores their roles in sucrose unloading and providing substrates for shoot growth. Its high sucrose affinity suggests that the Bo beta fruct2-encoded enzyme is important for maintaining the sucrose gradient between source and sink organs, while the predominant expression of Bo beta fruct3 in regions of active cell differentiation and expansion suggests functions in osmoregulation and cell enlargement.
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PMID:Molecular cloning and functional identification of invertase isozymes from green bamboo Bambusa oldhamii. 1660 37

Invertase inhibitor was extracted from potato tubers and purified nearly 1000-fold. The purification procedure involved precipitation at pH 4.0, fractionation with ammonium sulfate, adsorption on alumina Cgamma gel, and gel filtration on Sephadex G-100 and DEAE-Sephadex A-50. The product obtained was homogeneous to electrophoresis on polyacrylamide gel. Exclusion chromatography on Sephadex G-100 indicated a molecular weight of about 17,000. The inhibitor did not inhibit yeast, Neurospora, and several plant invertases. It completely inhibited potato tuber invertase and a number of other plant invertases. Some plant invertases were partially inhibited.
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PMID:Invertase inhibitor from potatoes: purification, characterization, and reactivity with plant invertases. 1665 19

As measured 7, 14, and 21 days after the application of 10(-2) M vanadyl sulfate solution to the foliage of 4.5-month-old sugar beet plants, significantly less growth of the leaves and an increase in the sucrose content of the storage root resulted. Accompanying these alterations were a higher rate of carbon dioxide fixation, a lower rate of respiration, and a decreased rate of nitrate reductase, glutamic-pyruvic transaminase, phosphatase, and invertase activity. The enzymes of sucrose synthesis, sucrose synthetase, sucrose phosphate synthetase and uridine diphosphate glucose-pyrophosphorylase were stimulated. The content of reducing sugar, nitrite N, amino acids and protein was less, and that of nitrate N was greater in the vanadium-treated plants. In the majority of cases the greatest magnitude of change occurred during the first 7 days following treatment. The changes in growth and chemical composition are believed to be closely related to the stimulation or inhibition of the various enzymes by vanadyl sulfate.
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PMID:Effect of Vanadium on Growth, Chemical Composition, and Metabolic Processes of Mature Sugar Beet (Beta vulgaris L.) Plants. 1665 5

Fruit of domesticated tomato (Lycopersicon esculentum) accumulate primarily glucose and fructose, whereas some wild tomato species, including Lycopersicon chmielewskii, accumulate sucrose. Genetic analysis of progeny resulting from a cross between L. chmielewskii and L. esculentum indicated that the sucrose-accumulating trait could be stably transferred and that the trait was controlled by the action of one or two recessive genes. Biochemical analysis of progeny resulting from this cross indicated that the sucrose-accumulating trait was associated with greatly reduced levels of acid invertase, but normal levels of sucrose synthase. Invertase from hexose-accumulating fruit was purified and could be resolved into three isoforms by chromatofocusing, each with isoelectric points between 5.1 and 5.5. The invertase isoforms showed identical polypeptide profiles on sodium dodecyl sulfate polyacrylamide gel electrophoresis, consisting of a primary 52 kilodalton polypeptide and two lower molecular mass polypeptides that appear to be degradation products of the 52 kilodalton polypeptide. The three invertase isoforms were indistinguishable based on pH, temperature, and substrate concentration dependence. Immunological detection of invertase indicated that the low level of invertase in sucrose-accumulating fruit was due to low levels of invertase protein rather than the presence of an invertase inhibitor. Based on comparison of genetic and biochemical data we speculate that a gene either encoding tomato fruit acid invertase or one required for its expression, plays an important role in determining sucrose accumulation.
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PMID:Sink Metabolism in Tomato Fruit : IV. Genetic and Biochemical Analysis of Sucrose Accumulation. 1666 87

Here it is reported that sucrose synthase can be readily measured in growing wild tomato fruits (Lycopersicon chmielewskii) when suitable methods are adopted during fruit extraction. The enzyme also was present in fruit pericarp tissues, in seeds, and in flowers. To check for novel characteristics, the wild tomato fruit sucrose synthase was purified, by (NH(4))(2)SO(4) fraction and chromatography with DE-32, Sephadex G-200, and PBA-60, to one major band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The following characteristics were obtained: native protein relative molecular weight 380,000; subunit relative molecular weight 89,000; K(m) values with: sucrose 53 millimolar, UDP 18.9 micromolar, UDP-glucose 88 micromolar, fructose 8.4 millimolar; pH optima between 6.2 to 7.3 for sucrose breakdown and 7 to 9 for synthesis; and temperature optima near 50 degrees C. The enzyme exhibited a high affinity and a preference for uridylates. The enzyme showed more sensitivity to divalent cations in the synthesis of sucrose than in its breakdown. Sink strength in tomato fruits also was investigated in regard to sucrose breakdown enzyme activities versus fruit weight gain. Sucrose synthase activity was consistently related to increases in fruit weight (sink strength) in both wild and commercial tomatoes. Acid and neutral invertases were not, because the published invertase activity values were too variable for quantitative analyses regarding the roles of invertases in tomato fruit development. In rapidly growing fruits of both wild and commercially developed tomato plants, the activity of sucrose synthase per growing fruit, i.e. sucrose synthase peak activity X fruit size, was linearly related to final fruit size; and the activity exceeded fruit growth and carbon import rates by at least 10-fold. In mature, nongrowing fruits, sucrose synthase activities approached nil values. Therefore, sucrose synthase can serve as an indicator of sink strength in growing tomato fruits.
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PMID:Sucrose Synthase in Wild Tomato, Lycopersicon chmielewskii, and Tomato Fruit Sink Strength. 1666 41

The present investigation deals with purification and thermal characterization of an acid invertase produced by Fusarium solani in submerged culture. The maximum enzyme activity (9.90 U mL(-1)) was achieved after 96 h of cultivation at pH 5.0 and 30 degrees C in a basal medium containing molasses (2%) as the carbon and energy source supplemented with 1% peptone. Invertase was purified by ammonium sulfate fractionation and column chromatography on DEAE-cellulose and Sephadex G-200. The purified enzyme was proven to be homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular mass of the enzyme was 65 kDa. The optimum pH and temperature for activity were 2.6 and 50 degrees C, respectively. The Km value for sucrose was 3.57 mM with an activation energy of 4.056 kJ mol(-1). Enthalpies of activation (DeltaH) were decreased while entropies (DeltaS) of activation increased at higher temperatures. The effects of alpha-chymotrypsin and 4 M urea were tetraphasic with periodic gain and loss of enzyme activity. A possible explanation for the thermal inactivation of invertase at higher temperatures is also discussed.
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PMID:Studies on kinetics and thermostability of a novel acid invertase from Fusarium solani. 1678 6

The current study was conducted to investigate the effects of high dietary concentrations of Zn as zinc oxide and Cu as copper sulfate on the activity of digestive enzymes in the pancreas and the intestinal mucosa, intestinal morphology, and mucin histochemistry in pigs after weaning. Thirty-two pigs were weaned at 4 wk of age. The pigs were fed standard weaning diets supplemented with Zn (100 or 2,500 ppm) and Cu (0 or 175 ppm) in a 2 x 2 factorial arrangement of treatments for a 14-d period. In pancreatic tissue, the activity of amylase, carboxypeptidase A, chymotrypsin, trypsin, and lipase increased (P < 0.01) in pigs fed 2,500 ppm of Zn, whereas the activity of carboxypeptidase B and carboxylester hydrolase was unaffected. Copper had no effect on the activity of pancreatic enzymes. In small intestinal contents, the total activity of amylase and carboxypeptidase A was greater in pigs fed 100 ppm of Zn (P < 0.05), whereas feeding 2,500 ppm of Zn increased the chymotrypsin activity (P < 0.001). The remaining enzymes were unaffected by dietary Zn concentration. The villi were longer in the cranial small intestine (P < 0.001) in pigs fed 100 ppm of Zn than in pigs fed 2,500 ppm of Zn, but otherwise there were no clear effects of Zn and Cu supplementation on intestinal morphology. In the cranial small intestine, the activity of maltase (P < 0.001), sucrase (P < 0.001), and lactase was greater in pigs fed 100 ppm of Zn, even though there was a Zn x Cu interaction (P < 0.05) in lactase activity. In the middle and caudal small intestine, no clear differences between dietary treatments were observed. The activity of gamma-glutamyl transpeptidase in the intestinal mucosa was not affected by dietary Zn or Cu. In pigs fed 100 ppm of Zn, the activity of aminopeptidase N was greater in the caudal small intestine, but dietary Zn or Cu had no effect on aminopeptidase N in the cranial and middle small intestine. No effect of dietary Zn or Cu supplementation was found on carbohydrate histochemistry in the caudal small intestine, whereas high dietary Zn increased the area of neutral, acidic, and sulfomucins in the cecum (P < 0.01) and in the colon (P < 0.001). In summary, high dietary Zn increased the activity of several enzymes in the pancreatic tissue and increased the mucin staining area in the large intestine, whereas Cu had no clear effect on these variables. However, no definite answers were found as to how the growth promoting and diarrhea reducing effects of excess dietary Zn are exerted.
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PMID:Influence of dietary zinc and copper on digestive enzyme activity and intestinal morphology in weaned pigs. 1709 23

The synthesis of new chain-extended sulfonium and selenonium salts of 1,4-anhydro-4-thio-(or 4-seleno)-d-arabinitol, analogues of the naturally occurring glycosidase inhibitor salacinol, is described. Nucleophilic attack at the least hindered carbon atom of 4,6-O-benzylidene-2,5-di-O-p-methoxybenzyl-d-mannitol-1,3-cyclic sulfate by 2,3,5-tri-O-p-methoxybenzyl-1,4-anhydro-4-thio-(or 4-seleno)-d-arabinitol gave the sulfonium and selenonium sulfates, respectively. Subsequent deprotection with trifluoroacetic acid yielded the target compounds. In these analogues, an extended polyhydroxylated aliphatic side chain has been incorporated while maintaining the stereochemistry of C-2' and C-3' of salacinol or blintol. These compounds were designed to probe the premise that they would bind with higher affinity to glucosidases than salacinol because the extra hydroxyl groups in the acyclic chain would make favorable polar contacts within the active site. Both target compounds inhibited recombinant human maltase glucoamylase, one of the key intestinal enzymes involved in the breakdown of glucose oligosaccharides in the small intestine, with Ki values in the low micromolar range. Comparison of these values to those of related compounds synthesized in previous studies has provided a better understanding of structure-activity relationships and the optimal stereochemistry at the different stereogenic centers required of an inhibitor of this enzyme. With respect to chain extension, the configurations at C-2' and C-4' are critical for activity, the configuration at C-3', bearing the sulfate moiety, being unimportant. The desired configuration at C-5' is also specified. However, comparison of the activities of the chain-extended analogues with those of salacinol and blintol indicates that there is no particular advantage of the chain-extension relative to salacinol or blintol. These results are similar to those reported earlier for kotalanol, a 7-carbon-extended derivative, versus salacinol against rat intestinal maltase, sucrase, and isomaltase.
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PMID:New chain-extended analogues of salacinol and blintol and their glycosidase inhibitory activities. Mapping the active-site requirements of human maltase glucoamylase. 1719 97


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