Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High activity alkaline protease was obtained when the enzyme was immobilized on Dowex MWA-1 (mesh 20-50) with 10% glutaraldehyde in chilled phosphate buffer (M/15, PH 6.5). Activity yields of the protease and rennet were 27 and 29, respectively. The highest activities appeared at 60 degrees C, pH 10 for alkaline protease and 50 degrees C, pH 4.0 for rennet. The properties of both proteases were not essentially changed by the immobilization except that the Km values of both enzymes were increased about tenfold as a result of immobilization. Both proteases in the immobilized state were more stable than those in the free state at 60 degrees C. Other peptide hydrolases, beta-galactosidase, invertase, and glucoamylase, were successfully immobilized with high activities, but lipase, hexokinase, glucose-6-phosphate dehydrogenase, and xanthine oxidase became inactive.
 ...
PMID:Preparation and properties of proteases immobilized on anion exchange resin with glutaraldehyde. 2 75

The denaturation of eight purified yeast enzymes, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, alcohol dehydrogenase, beta-fructosidase, hexokinase and glucose-6-phosphate isomerase, promoted under controlled conditions by the free fatty acids myristic and oleic, is selective. Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1 oxidoreductase, EC 1.1.1.49) is extremely sensitive to destabilization and was studied in greater detail. Results show that chain length and degree of unsaturation of fatty acids are important to their destabilizing effect, and that ligands of the enzyme can afford protection. The denaturation process results in more than one altered form. These results can be viewed in the perspective of the possibility that amphipathic substances, and in particular free fatty acids, may play a role for enzyme degradation in vivo, by initiating steps of selective denaturation.
 ...
PMID:Selective denaturation of several yeast enzymes by free fatty acids. 35 87

Sucrose catabolism was studied in Rhodopseudomonas capsulata. Sucrose was hydrolysed by the action of a constitutive cytoplasmic sucrase. The use of a glucose-6-phosphate dehydrogenase-deficient mutant and radiorespirometric experiments demonstrated that both the glucose and fructose moieties of sucrose were catabolized via the Entner-Doudoroff pathway. This result was confirmed by enzyme analysis and studies on sugar assimilation. All the enzymes of the Entner-Doudoroff pathway were present in bacteria grown on secrose but fructokinase (EC 1.7.1.4) activity was relatively low. In contrast, phosphoenolpyruvate:fructose phosphotransferase and 1-phosphofructokinase, the key enzymes for the catabolism of exogenous fructose, were only partially induced. Bacteria grown on sucrose and treated with chloramphenicol were, therefore, not able to assimilate exogenous fructose. We conclude that under these conditions endogenous fructose is catabolized via the Entner-Douboroff pathway, while exogenous fructose is degraded via fructose 1-phosphate and the Embden-Meyerhof pathway.
 ...
PMID:An alternative pathway for the degradation of endogenous fructose during the catabolism of sucrose in Rhodopseudomonas capsulata. 64 27

mRNA steady-state levels and activities of enzymes of intermediary carbon metabolism (hexokinase, phosphoglucoisomerase, phosphofructokinase, glucose-6-phosphate dehydrogenase, phosphoglucomutase) and glucose-regulated enzymes (pyruvate decarboxylase, pyruvate dehydrogenase, invertase, alcohol dehydrogenase) were determined in glucose-limited continuous cultures of an industrial strain of Saccharomyces cerevisiae at different dilution rates (D) ranging from 0.05 to 0.315 h-1. The activity of most enzymes measured remained constant over this range except for alcohol dehydrogenase I/II which decreased proportionally with increasing dilution rate. A decrease in phosphoglucomutase activity occurred with increasing dilution rate but reached a minimum at D 0.2 h-1 and from thereon remained constant. A decrease in pyruvate decarboxylase activity and a slight decrease in phosphoglucoisomerase activity was observed. At D 0.29/0.315 h-1, at the onset of the Crabtree effect, most glycolytic enzymes remained constant except for pyruvate decarboxylase and glucose-6-phosphate dehydrogenase which increased at D 0.315 h-1 and alcohol dehydrogenase I/II which decreased. The ADHI/II and PDC1 mRNA levels obtained at the different dilution rates were in accordance with the activity measurements. The mRNA level of HXK1 decreased with increasing dilution rates, whereas the transcription of HXK2 increased. Pyruvate dehydrogenase (PDA1) and PGI1 mRNA fluctuated but no significant change could be detected. These results indicate that there is no transcriptional or translational regulation of glycolytic flux between D 0.05 h-1 and 0.315 h-1 except at the branch point between oxidative and fermentative metabolism (pyruvate decarboxylase/pyruvate dehydrogenase) at D 0.315 h-1. Surprisingly regulation of the Crabtree effect does not seem to involve transcriptional regulation of PDA1.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Analysis of transcription and translation of glycolytic enzymes in glucose-limited continuous cultures of Saccharomyces cerevisiae. 148 26

A blotting method is described to detect enzymes that do not normally yield a colored product. The method can be used for dot blotting as well as blotting after gel electrophoresis of many enzymes if the reactions they catalyze can be coupled to an oxidase or a dehydrogenase. The latter, designated "auxiliary enzymes," are preimmobilized on membranes of nitrocellulose or positively charged nylon and the reaction they catalyze is coupled with reduction of tetrazolium salt to yield colored formazan on areas of the transfer membrane occupied by the blotted enzymes. In the examples reported here, preimmobilized glucose oxidase, L-amino acid oxidase, xanthine oxidase, malate dehydrogenase, and a mixture of hexokinase and glucose-6-phosphate dehydrogenase were used as auxiliary enzymes to detect blotted invertase, leucine aminopeptidase, purine nucleoside phosphorylase, fumarase, and adenylate kinase, respectively. Detection limits varied, but never exceeded 100 ng for these enzymes. After blotting from polyacrylamide gels, the fumarase assay was the most sensitive of those investigated, detecting 10 ng of enzyme used for electrophoresis. Invertase, a glycoprotein, was detected with higher sensitivity on nitrocellulose membranes when concanavalin A was present on the membrane in addition to the auxiliary enzyme, glucose oxidase. On blots from isoelectric focusing gels, the assay detected two isozymes of purine nucleoside phosphorylase in a sample from calf spleen and at least five isozymes of this enzyme in lysates from human red cells.
 ...
PMID:Activity staining of blotted enzymes by reaction coupling with transfer membrane-immobilized auxiliary enzymes. 245 38

Juvenile white sturgeon were fed isonitrogenous diets containing 27.2% glucose, fructose, maltose, sucrose, lactose, dextrin, raw corn starch or cellulose for 8 wk. Growth, body composition, plasma chemistry (with the exception of glucose), and liver glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), malic enzyme (EC 1.1.1.40) and isocitrate dehydrogenase (ICDH, 1.1.1.42) activities of sturgeon were significantly (P less than 0.05) affected by the different dietary carbohydrate sources. Sturgeon fed either the maltose or glucose diets had the highest percent energy retained, followed by those fed either the dextrin, raw corn starch or sucrose diets, whereas those fed either the lactose, fructose or cellulose diets had the lowest. Sturgeon fed either the maltose or glucose diets were hyperlipidemic, having twice the amount of plasma total lipid, triacylglycerol and total cholesterol as fish fed the other carbohydrate sources. These two carbohydrate sources were also more lipogenic: maltose- or glucose-fed sturgeon had significantly higher body lipid and liver G6PDH, malic enzyme, and ICDH activities. The poor ability of sturgeon to utilize either sucrose or lactose appears to be due to low intestinal sucrase (EC 3.2.1.48) and lactase (EC 3.2.1.108) activities. Intestinal aminopeptidase (EC 3.4.11.11), maltase (EC 3.2.1.20), sucrase and lactase activities of sturgeon were not affected by feeding different carbohydrate sources for 8 wk.
 ...
PMID:Ability of juvenile white sturgeon (Acipenser transmontanus) to utilize different carbohydrate sources. 272 21

Synchronous cultures of Saccharomyces cerevisiae prepared by selection of small unbudded cells from an elutriating rotor were used to measure trehalase activity during the cell cycle. After the small cells had been removed from the rotor, the remainder was used to prepare asynchronous control cultures. Both synchronous and control cultures were studied for two cell cycles. In asynchronous cultures the trehalase activity of crude cell lysates rose continuously. In synchronized populations trehalase activity increased from the beginning of budding onwards. However, around the period of cell division the enzyme activity dropped rapidly but transiently by more than 5-fold. The same changes were found during the second budding cycle. Measurements of invertase and glucose-6-phosphate dehydrogenase activities in the same synchronous and asynchronous cultures revealed a continuous increase for both enzymes. Incubation of cell lysates with cAMP-dependent protein kinase before assaying for trehalase resulted in a 2-fold enhancement of enzyme activity in asynchronous control cultures. In synchronized cells this treatment also led to a significant stimulation of trehalase activity, and largely abolished the cell-cycle-dependent oscillatory pattern of enzyme activity. These results suggest that the activity of trehalase during the cell cycle is regulated, presumably at the post-translational level, by a phosphorylation-dephosphorylation mechanism.
 ...
PMID:Regulation of trehalase activity during the cell cycle of Saccharomyces cerevisiae. 305 78

Enzyme immunoassays for 17 alpha-hydroxyprogesterone (17-OHP) were developed. Horseradish peroxidase (HRP), glucose oxidase (GOD), invertase (INV) and glucose-6-phosphate dehydrogenase (G6PDH) were used as label enzymes. Double antibody coated beads or tubes were used for separating the bound and free fractions. Antisera used were prepared by using 4-carboxyethylthio-17-OHP and 3-carboxymethyl oxime-17-OHP-bovine serum albumin as immunogens. The bridge heterologous system was more sensitive than other site heterologous and homologous systems. The minimum amounts of 17-OHP detected were 0.25 and 1.0 pg/tube for fluorescence EIAs using HRP and GOD, and 0.1, 10 and 0.1 pg/tube for chemiluminescence EIAs using GOD, INV and G6PDH, respectively. The reproducibility and correlation with RIA were also studied. The present study demonstrates the feasibility of a neonatal screening for congenital adrenal hyperplasia.
 ...
PMID:Fluorescence and chemiluminescence enzyme immunoassays of 17 alpha-hydroxyprogesterone in dried blood spotted on filter paper. 332 May 34

In order to determine whether the changes in the activities and mRNA levels of enzymes involved in intermediary carbon metabolism previously observed in glucose-limited continuous cultures (Sierkstra et al., 1992a) were glucose specific, we have analysed their regulation in a galactose-limited continuous culture of Saccharomyces cerevisiae. The Vmax of the galactose uptake system was shown to be dilution rate (D) dependent, comparable with the high-affinity glucose uptake. The maximum uptake was observed at D 0.2 h-1 (0.25 mmol min-1 per g) and the minimum uptake (0.1 mmol min-1 per g) at D 0.05 h-1 and 0.3 h-1. The aerobic fermentation of galactose occurred at D 0.275-0.3 h-1 which is identical to the results obtained in glucose-limited continuous cultures of this strain. Because galactose is not a repressing carbon source, this demonstrates that the Crabtree effect is not mediated by, or in any way related to glucose repression. Moreover, invertase and hexokinase I mRNA levels (both subject to glucose repression at the transcriptional level) were present when the yeast produced ethanol in galactose- and glucose-limited continuous cultures. In glucose-limited continuous cultures a decrease in alcohol dehydrogenase (I and II) mRNA levels and activity and phosphoglucomutase activity was observed with increasing dilution rates. In addition, at D 0.3 h-1, when the yeast produced ethanol, glucose-6-phosphate dehydrogenase and pyruvate decarboxylase were induced and a decrease in respiration was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Regulation of glycolytic enzymes and the Crabtree effect in galactose-limited continuous cultures of Saccharomyces cerevisiae. 836 13

A powerful technique is described to localize the activities of a range of enzymes in a wide variety of plant tissues. The method is based on the coupling of the enzymatic reaction to the reduction of NAD and subsequent reduction and precipitation of nitroblue tetrazolium. Enzymes that did not reduce NAD could be visualized by coupling their activities to glucose-6-phosphate dehydrogenase activity via one or more intermediary 'coupling' enzymes. The method is shown to be applicable for the detection of the activities of hexokinase, fructokinase, sucrose synthase, uridine 5'-diphospho-glucose pyrophosphorylase, ADP-glucose pyrophosphorylase, phosphoglucomutase, and phosphoglucose isomerase. It could be used for all tissues tested, including green leaves, stems, roots, fruits, and seeds. The method is specific, very sensitive, and has a high spatial resolution, giving information at the cellular and the subcellular level. The localization of sucrose synthase, invertase, and uridine 5'-diphospho-glucose pyrophosphorylase in transgenic potato plants, carrying a cytokinin biosynthesis gene, is studied and compared with wild-type plants.
 ...
PMID:In situ staining of activities of enzymes involved in carbohydrate metabolism in plant tissues. 1180 40


1 2 3 Next >>