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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)

Neutral invertase from nodules of chickpea (Cicer arietinum L.) was isolated and purified by ammonium sulphate fractionation, gel filtration and DEAE-cellulose column chromatography. The purified enzyme was stable between 0 to 40 degrees C beyond which it was irreversibly denatured. Optimum temperature and pH of the enzyme were 37 degrees C and 7.0, respectively. K(m) for sucrose was 14.2 mM and Vmax was 4.8 mumole hr-1. The enzyme was inhibited by several metal ions. From the temperature effect on K(m) and Vmax values, the energy of activation (Ea), enthalpy change (delta H) and entropy change (delta S) of the enzyme were calculated to be 147 kJmol-1, -4.10 kJmol-1 and -2.33 JK-1mol-1, respectively. By employing photo-oxidation and chemical modification and by studying the effect of pH on K(m) and Vmax, the involvement of sulphydryl-, imidazole- and alpha-amino groups in the active site of the enzyme has been indicated.
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PMID:Purification and characterization of neutral invertase from chickpea nodules. 959 35

Fructosyltransferase (EC.2.4.1.9) and invertase (EC.3.2.1.26) have been purified from the crude extract of Aspergillus niger AS0023 by successive chromatographies on DEAE-sephadex A-25, sepharose 6B, sephacryl S-200, and concanavalin A-Sepharose 4B columns. On acrylamide electrophoresis the two enzymes, in native and denatured forms, gave diffused glycoprotein bands with different electrophoretic mobility. On native-PAGE and SDS-PAGE, both enzymes migrated as polydisperse aggregates yielding broad and diffused bands. This result is typical of heterogeneous glycoproteins and the two enzymes have proved their glycoprotein nature by their adsorption on concanavalin A lectin. Fructosyltransferase (FTS) on native PAGE migrated as two enzymatically active bands with different electrophoretic mobility, one around 600 kDa and the other from 193 to 425 kDa. On SDS-PAGE, these two fractions yielded one band corresponding to a molecular weight range from 81 to 168 kDa. FTS seems to undergo association-dissociation of its glycoprotein subunits to form oligomers with different degrees of polymerization. Invertase (INV) showed higher mobility corresponding to a molecular range from 82 to 251 kDa, on native PAGE, and from 71 to 111 kDa on SDS-PAGE. The two enzymes exhibited distinctly different pH and temperature profiles. The optimum pH and temperature for FTS were found to be 5.8 and 50 degrees C, respectively, while INV showed optimum activity at pH 4.4 and 55 degrees C. Metal ions and other inhibitors had different effects on the two enzyme activities. FTS was completely abolished with 1 mM Hg(2+) and Ag(2+), while INV maintained 72 and 66% of its original activity, respectively. Furthermore, the two enzymes exhibited distinctly different kinetic constants confirming their different nature. The K(m) and V(m) values for each enzyme were calculated to be 44.38 mM and 1030 micromol ml(-1)min(-1) for FTS and 35.67 mM and 398 micromol ml(-1) min(-1) for INV, respectively. FTS and INV catalytic activity was dependent on sucrose concentration. FTS activity increased with increasing sucrose concentrations, while INV activity decreased markedly with increasing sucrose concentration. Furthermore, INV exhibited only hydrolytic activity producing exclusively fructose and glucose from sucrose, while FTS catalyzed exclusively fructosyltransfer reaction producing glucose, 1-kestose, nystose and fructofuranosyl nystose. In addition, at 50% sucrose concentration FTS produced fructooligosaccharides at the yield of 62% against 54% with the crude extract.
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PMID:Purification and partial characterization of fructosyltransferase and invertase from Aspergillus niger AS0023. 1093 62

The main component of inulinase was purified from fermentation broth of Aspergillus niger 319 to homogeneity by using ammonium sulfate fraction, ion-exchange chromatography on DEAE-cellulose column and Sephadex G-100 gel filtration. The specific activity was as 67 folds at the fermentation broth, and the yield was 25.5%. The inulinase, containing 13.92% of carbohydrate, was a monomer protein with a molecular weight of 28,000 Dalton; and its isoelectric point was pH 5.4. The optimal pH and temperature of the inulinase was pH 5.0 and 60 degrees C, respectively. The enzyme was strongly inhibited by heavy metal ions of Hg2+, Pb2+ and Cu2+. The optimal substrate for the enzyme was inulin and the product was only fructose, but it also had invertase activity with the I/S of 0.348. The Km and Vm of the inulinase was 6.25 mmol/L and 67.11 mumol.mg-1.min-1, respectively.
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PMID:[Purification and properties of inulinase from Aspergillus niger]. 1118 61

Invertase and urease are enzyme entities highly associated with the cells of the astaxanthin-producer yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma) during any stage of its cell growth cycle. In this study cellobiose was a more efficient carbon source than sucrose or its hexose counterparts for invertase expression. Extensive ultrasonication or abrasion with glass pearls were required in order to promote enzyme release. In contrast to the yeast whose growth declines above 27 degrees C, the released enzymes displayed a higher optimum temperature range when assayed in vitro. Isoforms from both enzymes could be resolved either by FPLC on DEAE-Sepharose or by an affinity approach on immobilized Concanavalin. The zymogram for invertase showed a pI somewhat less acidic than that of the similar enzyme from S. cerevisiae.
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PMID:Invertase and urease activities in the carotenogenic yeast Xanthophyllomyces dendrorhous (formerly Phaffia rhodozyma). 1185 6

Invertase from S. cerevisiae has been immobilized by ionic adsorption on Sepabeads fully coated with PEI. The enzyme was strongly adsorbed on the support (no desorption of the invertase was found under conditions in which all of the enzyme was released from conventional anionic exchanger supports (e.g., DEAE-agarose)). Nevertheless, the enzyme could still be desorbed after its inactivation, and new fresh enzyme could be adsorbed on the supports without detrimental effects on enzyme loading. This is a multimeric enzyme, its minimal oligomerization active state being the dimer, but under certain conditions of pH and concentration it may give larger multimers. Very interestingly, results suggested that the adsorption of the enzyme on this large and flexible polymeric bed was able to freeze some of the different oligomeric structures of the enzyme. Thus, we have found that the enzyme immobilized at certain pH values (pH 8.5) and high enzyme concentration, in which the main enzyme structure is the tetramer, was more stable than immobilized preparations produced in conditions under which oligomerization was not favorable (dimers at low enzyme concentration) or it was too high (e.g., hexamers-octamers at low pH value). The optimal enzyme preparation remained fully active after a 15-day incubation at 50 degrees C and pH 4.5 (conditions of standard industrial use) and presented an optimal temperature approximately 5 degrees C higher than that of soluble enzyme.
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PMID:Reversible immobilization of invertase on Sepabeads coated with polyethyleneimine: optimization of the biocatalyst's stability. 1246 55

Two isozymes (AIV I and AIV II) of soluble acid invertase (EC 3.2.1.26) were purified from Japanese pear fruit through procedures including (NH(4))(2)SO(4) precipitating, DEAE-Sephacel column chromatography, Concanavalin A (ConA)-Sepharose affinity chromatography, hydroxyapatite column chromatography and Mono Q HR 5/5 column chromatography. The specific activities of purified AIV I and AIV II were 2670 and 2340 (nkat/mg protein), respectively. AIV I was a monomeric enzyme of 80 kDa, while AIV II may be also a monomeric enzyme, which is easy to be cleaved to 52 kDa and 34 kDa polypeptide during preparation by SDS-PAGE. The Km values for sucrose of AIV I and AIV II were 3.33 and 4.58 mM, respectively, and optimum pH of both enzyme activities was pH 4.5.
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PMID:Purification and characterization of two soluble acid invertase isozymes from Japanese pear fruit. 1271 Nov 32

Acetyl esterase (AE) activity present in the culture filtrate of Termitomyces clypeatus was separated into lower molar mass (LMM) and higher molar mass (HMM) protein fractions during BioGel P-200 gel chromatography. AE was purified as a 30 kDa nonglycosylated protein from LMM fractions by CM-Sepharose ion exchange chromatography and HPGPLC. Although the HMM fraction had a number of enzyme activities (sucrase, beta-xylosidase, beta-glucosidase, and alpha-L-arabinofuranosidase) other than AE, protein present in the fraction was eluted as a single protein peak in HPGPLC and gave a single band in native PAGE. The fraction, subsequently purified by DEAE-Sephadex chromatography, was a SDS-PAGE homogeneous 80 kDa glycoprotein, but with both AE and cellobiase activities. The aggregate dissociated during ConA-Sepharose chromatography and 30 kDa AE and 56 kDa glycosylated cellobiase were purified separately. The dissociation caused significant loss of cellobiase activity but not that of AE. AE purified from both HMM and LMM fractions was characterized to be the same enzyme in terms of molar masses, pI (7.3), and other physicochemical properties. AE as an aggregate with cellobiase showed higher thermostability, temperature optimum, and resistance toward chemical denaturants than those of purified AE. Compared to cellobiase purified earlier from the same fungus, the enzyme present with AE in the aggregate also showed higher catalytic activity, thermostability, and temperature optimum. The study indicated that the formation of such SDS-resistant enzyme aggregate was associated with significant changes in the physicochemical properties of the enzymes, mainly toward improvement of rigidity of enzymes, and sometimes with the improvement of catalytic activity.
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PMID:Protein-protein interaction conferring stability to an extracellular acetyl (xylan) esterase produced by Termitomyces clypeatus. 1279 Jun 30

Two proteinaceous invertase inhibitors, designated ITI-L and ITI-R, were purified to electrophoretic homogeneity. ITI-L was purified from acetone powder of sweet potato leaves through sequential steps entailing buffer extraction, acid treatment, DEAE-Sephacel ion-exchange chromatography, and Sephacryl S-100 gel filtration. ITI-R was purified from sweet potato tuberous roots by sequentially applying buffer extraction, Con A-Sepharose affinity chromatography, DEAE-Sephacel ion-exchange chromatography, Sephacryl S-200, and Superose 12 gel filtration. The optimal pHs for interaction between ITI-L and ITI-R and acid invertase from sweet potato leaves were 5.5 and 5.0, respectively. The molecular masses of ITI-L and ITI-R were 10 and 22 kDa, respectively, as estimated by both gel filtration and SDS-PAGE. Both inhibitors were thermostable (90% of the activity remained after incubation at 100 degrees C for 20 min), and Western blotting showed them to be immunologically related.
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PMID:Invertase inhibitors from sweet potato (Ipomoea batatas): purification and biochemical characterization. 1470 16

A scheme has been developed for isolation and purification of the enzyme with alpha-N-acetylgalactosaminidase and alpha-galactosidase activities which included fractionation by ammonium sulphate and chromatography on TSK-gels Toyopearl HW-60 and Fractogel DEAE-650-s and Sepharose 6B. The enzyme was purified 600 times with the yield of 28%. The enzyme preparation did not contain fucosidase, invertase and proteolytic activities. Molecular mass of the enzyme from the data of gel-filtration on Sepharose 6B was 430 kDa, according to the data of electrophoresis in DS-PAAG--70 kDa. It is shown that acidic and hydrophobic aminoacids prevail in the enzyme molecule, the carbohydrate component containing galactose, mannose, glucosamine and two nonidentified hexosamines is also present there. The enzyme preparation is stable during 48 hours at 20 degrees C; its pH-optimum is at pH 3.5-4.1. Michaelis constants concerning n-nitrophenyl-alpha-N-acetylgalactopyranoside and n-nitrophenyl-alpha-D-galactopyranoside were 1.18 and 1.25 mM, respectively.
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PMID:[Purification and physico-chemical properties of glycosidase of Aspergillus niger 185sh]. 1507 44

The present study analyzed the existence of carbohydrases in camel pancreas compared to some other ruminants. Disaccharidases (maltase, cellobiase, lactase, trehalase and sucrase), glucoamylase and alpha-amylase were detected in pancreas of camel, sheep, cow and buffalo. Enzyme levels in sheep were lower than in the other ruminants. The highest level was detected for alpha-amylase (EC 3.2.1.2). Moderate activity levels were detected for glucoamylase (EC 3.2.1.3) and maltase (EC 3.2.1.20), while other disaccharidases showed very low activity. The results suggested that, in addition to alpha-amylase, glucoamylase and maltase may be synthesized and secreted from pancreas to the small intestine in ruminants. Camel pancreatic glucoamylase was purified and characterized. The purification procedure included glycogen precipitation and chromatography on DEAE-Sepharose and Sepharose 6B. The molecular mass was 58 kDa for native and denatured enzyme using gel filtration and SDS-PAGE, respectively. The enzyme had a pH optimum at 5.5 and a Km of 10 mg starch/mL with more affinity toward potato soluble starch than the other carbohydrates. Glucoamylase had a temperature optimum at 50 degrees C with heat stability up to 30 degrees C. The effect of different cations and inhibitors was examined. The camel pancreatic glucoamylase may possess an essential thiol.
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PMID:Carbohydrases in camel (Camelus dromedarius) pancreas. Purification and characterization of glucoamylase. 1562 12


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