scholarly journals Partial purification and properties of a β-N-acetylglucosaminidase from the fungus Sclerotinia fructigena

1973 ◽  
Vol 131 (2) ◽  
pp. 381-388 ◽  
Author(s):  
F. Reyes ◽  
R. J. W. Byrde

1. As cultures of the fungus Sclerotinia fructigena autolysed, the filtrates contained increasing quantities of a β-N-acetylglucosaminidase. 2. The enzyme was purified up to 42-fold by a combination of isoelectric focusing and gel filtration. 3. It ran as a single band in cellulose acetate strip electrophoresis and in isoelectric focusing (pI3.76). 4. The enzyme did not readily hydrolyse chitin or a glycopeptide with terminal N-acetylglucosamine residues, but rapidly degraded the N-acetylglucosamine dimer NN′-diacetylchitobiose; the monomer was readily utilized by the fungus as a nitrogen source. The Km value for hydrolysis of p-nitrophenyl β-2-acetamido-2-deoxy-d-glucopyranoside at 37°C was 2.0mm. The Sclerotinia enzyme was generally less susceptible to inhibition by 2-acetamido-2-deoxygluconolactone and other related sugars than the corresponding enzyme from other sources. Inhibition by excess of substrate was observed. 5. The culture filtrate also contained N-acetylgalactosaminidase activity; conflicting evidence was obtained as to whether the same enzyme was responsible for both hexosaminidase activities.

1993 ◽  
Vol 289 (2) ◽  
pp. 453-461 ◽  
Author(s):  
M Hrmova ◽  
G B Fincher

Three (1->3)-beta-D-glucan glucanohydrolase (EC 3.2.1.39) isoenzymes GI, GII and GIII were purified from young leaves of barley (Hordeum vulgare) using (NH4)2SO4 fractional precipitation, ion-exchange chromatography, chromatofocusing and gel-filtration chromatography. The three (1->3)-beta-D-glucanases are monomeric proteins of apparent M(r)32,000 with pI values in the range 8.8-10.3. N-terminal amino-acid-sequence analyses confirmed that the three isoenzymes represent the products of separate genes. Isoenzymes GI and GII are less stable at elevated temperatures and are active over a narrower pH range than is isoenzyme GIII, which is a glycoprotein containing 20-30 mol of hexose equivalents/mol of enzyme. The preferred substrate for the enzymes is laminarin from the brown alga Laminaria digitata, an essentially linear (1->3)-beta-D-glucan with a low degree of glucosyl substitution at 0-6 and a degree of polymerization of approx. 25. The three enzymes are classified as endohydrolases, because they yield (1->3)-beta-D-oligoglucosides with degrees of polymerization of 3-8 in the initial stages of hydrolysis of laminarin. Kinetic analyses indicate apparent Km values in the range 172-208 microM, kcat. constants of 36-155 s-1 and pH optima of 4.8. Substrate specificity studies show that the three isoenzymes hydrolyse substituted (1->3)-beta-D-glucans with degrees of polymerization of 25-31 and various high-M(r), substituted and side-branched fungal (1->3;1->6)-beta-D-glucans. However, the isoenzymes differ in their rates of hydrolysis of a (1->3;1->6)-beta-D-glucan from baker's yeast and their specific activities against laminarin vary significantly. The enzymes do not hydrolyse (1->3;1->4)-beta-D-glucans, (1->6)-beta-D-glucan, CM-cellulose, insoluble (1->3)-beta-D-glucans or aryl beta-D-glycosides.


1983 ◽  
Vol 29 (2) ◽  
pp. 242-246 ◽  
Author(s):  
Norman J. Novick ◽  
Max E. Tyler

An L-arabino-aldose dehydrogenase responsible for the oxidation of L-arabinose to L-arabino-γ-lactone has been purified 59-fold from L-arabinose grown cells of Azospirillum brasiliense. The dehydrogenase was found to be specific for substrates with the L-arabino-configuration at carbons 2, 3, and 4. Km values for L-arabinose of 75 and 140 μM were found with NADP and NAD as coenzymes, respectively. The enzyme had a pH optimum of 9.5 in glycine buffer and was stable when heated to 55 °C for 5 min. No enhancement of activity in the presence of any divalent cation or reducing agent tested was found. L-Arabinose dehydrogenase had a molecular weight of 175 000 as measured by the gel filtration technique.


1984 ◽  
Vol 224 (1) ◽  
pp. 171-179 ◽  
Author(s):  
I R Cottingham ◽  
A L Moore

The external NADH dehydrogenase has been purified from Arum maculatum (cuckoo-pint) mitochondria by phosphate washing, extraction with deoxycholate, ion-exchange and gel-filtration chromatography. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis shows, when the gel is silver-stained, that the purified enzyme contains two major bands of Mr 78 000 and 65 000 and a minor one of Mr about 76 000. It is not possible at present to determine which of these, or which combination, constitutes the dehydrogenase. The enzyme contains non-covalently bound FAD and a small amount of FMN. Since the conditions of purification lead to considerable loss of flavin and possibly iron-sulphur centres, it is not possible to decide with certainty whether the enzyme is a flavo- or ferroflavo-protein. The enzyme has been distinguished from the other NADH dehydrogenases on the basis of its substrate specificity, its capability of reducing electron acceptors such as ubiquinone-1 and 2,6-dichlorophenol-indophenol and its sensitivity towards Ca2+, EGTA and dicoumarol.


1977 ◽  
Vol 37 (03) ◽  
pp. 556-565 ◽  
Author(s):  
S. E Papaioannou ◽  
W. J Marsheck

SummaryAn extracellular protease SN 687, secreted by the soil bacterium isolate WM 122, has been purified by means of gel filtration, ammonium sulfate precipitation, DEAE-Sephadex and hydroxylapatite chromatography. Apparent homogeneity was ascertained by Polyacrylamide gel electrophoresis. The protease was inactivated by ethylenediamine tetracetic acid (EDTA) but not by diisopropylfluorophosphate (DFP), and it was partially inhibited by serum inhibitors. SN 687 was shown to be of high specific activity against casein and fibrin, but it did not hydrolyze L- lysine -methyl ester dihydrochloride (LME), p-tosyl-L-arginine-methyl ester hydrochloride (TAME) and N-benzoyl-L-tyrosine-ethyl ester hydrochloride (BTEE) synthetic substrates. The optimum pH for hydrolysis of casein was 7.5 and the molecular weight, as determined by gel filtration, was 31,000.


1979 ◽  
Vol 34 (9-10) ◽  
pp. 709-714 ◽  
Author(s):  
Joseph Veser ◽  
Peter Geywitz ◽  
Helmut Thomas

Abstract In an effort to investigate catechol methyltransferase activity in sources other than mammalian tissues and cells, a high level of enzyme activity was found in the yeast fungus Candida tropicalis CBS 94. Partial purification of the enzyme (approx. 550 fold with a recovery of 7%) could be achieved by using ion-exchange and gel filtration techniques. The molecular weight was estimated at 32,000 ± 2,000 by gel filtration on Sephadex G-100. In isoelectric focusing experiments on Sephadex G-75 the enzyme exhibited a pl-value o f 5.0 ± 0.1. In contrast to catechol methyltransferase from various mammalian tissues the enzyme activity was prepared from the pH 5-sediment. The substrate specifity is comparable to other catechol methyltransferases.


1970 ◽  
Vol 48 (5) ◽  
pp. 613-622 ◽  
Author(s):  
A. V. Emes ◽  
L. C. Vining

Phenylalanine ammonia-lyase (EC 4.3.1.5) was purified 40-fold from a cell homogenate of Streptomyces verticillatus. In many respects the enzyme was similar to phenylalanine ammonia-lyases isolated from plants and fungi. It was most active at pH 9.0 and the Km for L-phenylalanine was 1.6 × 10−4 M. It showed no requirement for metal ions but was inhibited by heavy metals, some sulfhydryl reagents, and carbonyl reagents. The Stokes' radius was estimated by gel filtration to be 5.45 nm. Sucrose gradient centrifugation gave an s20,w of 10.0, leading to calculated values of 226 000 and 1.61 for the molecular weight and frictional ratio, respectively, if a partial specific volume of 0.725 ml/g is assumed. The enzyme deaminated o-, m-, and p-fluoro-, p-chloro-, and p-methyl-phenylalanine but was without action on L-tyrosine. It was inhibited by trans-cinnamic acid and certain phenylalanine derivatives, as well as by some less closely related aromatic compounds, but not by trans-cinnamamide.


1988 ◽  
Vol 255 (3) ◽  
pp. 833-841 ◽  
Author(s):  
J D Erfle ◽  
R M Teather ◽  
P J Wood ◽  
J E Irvin

A 1,3-1,4-beta-D-glucanase (lichenase, 1,3-1,4-beta-D-glucan 4-glucanohydrolase, EC 3.2.1.73) from Bacteroides succinogenes cloned in Escherichia coli was purified 600-fold by chromatography on Q-Sepharose and hydroxyapatite. The cloned enzyme hydrolysed lichenin and oat beta-D-glucan but not starch, CM(carboxymethyl)-cellulose, CM-pachyman, laminarin or xylan. The enzyme had a broad pH optimum with maximum activity at approx. pH 6.0 and a temperature optimum of 50 degrees C. The pH of elution from a chromatofocusing column for the cloned enzyme was 4.7 (purified) and 4.9 (crude) compared with 4.8 for the mixed-linkage beta-D-glucanase activity in B. succinogenes. The Mr of the cloned enzyme was estimated to be 37,200 by gel filtration and 35,200 by electrophoresis. The Km values estimated for lichenin and oat beta-D-glucan were 0.35 and 0.71 mg/ml respectively. The major hydrolytic products with lichenin as substrate were a trisaccharide (82%) and a pentasaccharide (9.5%). Hydrolysis of oat beta-D-glucan yielded a trisaccharide (63.5%) and a tetrasaccharide (29.6%) as the major products. The chromatographic patterns of the products from the cloned enzyme appear to be similar to those reported for the mixed-linkage beta-D-glucanase isolated from Bacillus subtilis. The data presented illustrate the similarity in properties of the cloned mixed-linkage enzyme and the 1,3-1,4-beta-D-glucanase from B. subtilis and the similarity with the 1,4-beta-glucanase in B. succinogenes.


1977 ◽  
Vol 167 (3) ◽  
pp. 693-701 ◽  
Author(s):  
Peter Hechtman ◽  
Dorothy LeBlanc

Human liver extracts contain an activating protein which is required for hexosaminidase A-catalysed hydrolysis of the N-acetylgalactosaminyl linkage of GM2 ganglioside [N-acetylgalactosaminyl-(N-acetylneuraminyl) galactosylglucosylceramide]. A partially purified preparation of human liver hexosaminidase A that is substantially free of GM2 ganglioside hydrolase activity is used to assay the activating protein. The proceudres of heat and alcohol denaturation, ion-exchange chromatography and gel filtration were used to purify the activating protein over 100-fold from crude human liver extracts. When the purified activating protein is analysed by polyacrylamide-gel disc electrophoresis, two closely migrating protein bands are seen. When purified activating protein is used to reconstitute the GM2 ganglioside hydrolase activity, the rate of reaction is proportional to the amount of hexosaminidase A used. The activation is specific for GM2 ganglioside and and hexosaminidase A. The activating protein did not stimulate hydrolysis of asialo-GM2 ganglioside by either hexosaminidase A or B. Hexosaminidase B did not catalyse hydrolysis of GM2 ganglioside with or without the activator. Kinetic experiments suggest the presence of an enzyme–activator complex. The dissociation constant of this complex is decreased when higher concentrations of substrate are used, suggesting the formation of a ternary complex between enzyme, activator and substrate. Determination of the molecular weight of the activating protein by gel-filtration and sedimentation-velocity methods gave values of 36000 and 39000 respectively.


1982 ◽  
Vol 47 (4) ◽  
pp. 1139-1148 ◽  
Author(s):  
Karel Hauzer ◽  
Linda Servítová ◽  
Tomislav Barth ◽  
Karel Jošt

Post-proline endopeptidase was isolated from pig kidneys and partially purified. The procedure consisted of fractionation with ammonium sulphate, ion exchange chromatography on DEAE-Sephadex A-50, gel filtration on Sephadex G-200 and rechromatography on DEAE-Sephadex A-50. The preparation had 55 times higher specific activity than the crude extract and did not contain any contaminating enzymic activities. The enzyme cleaved a number of proline-containing peptides and was strictly specific in catalyzing the hydrolysis of the peptide bond on the carboxyl side of the proline residue. The optimum pH for the hydrolysis of the synthetic peptides benzyl-oxycarbonylglycyl-prolyl-leucyl-glycinamide and benzyloxycarbonyl-glycyl-proline β-naphtylamide was 7.8-8.0 and, in the case of benzyloxycarbonylglycyl-proline p-nitroanilide, 7.2 to 7.5. For the hydrolysis of the tetrapeptide benzyloxycarbonylglycyl-prolyl-leucyl-glycinamide, the Km value of 75 μ mol l-1 was obtained.


2016 ◽  
Vol 13 (2) ◽  
pp. 392-398
Author(s):  
Baghdad Science Journal

Catalase (EC 1.11.1.6) is a well known enzyme which exists in almost all living creatures exposing to oxygen (such as plants, bacteria, and animals). It is a very necessary enzyme to protect the cell from oxidative detriment by reactive oxygen species (ROS). The aim of this study is the partial purification and characterization of Catalase enzyme from Banana peels. In this study, fresh banana peels are treated with 70 % ethanol ,further separated with chloroform ,water and ethyl acetate respectively .The supernatant of the enzymatic sample which is treated with chloroform is loaded into gel filtration column with Sephadex G-100 (1.0 x 90 cm) equilibrated with pH7 buffer media (phosphate buffer 0.1 M). Kinetic studies of the purified enzyme activity are measured and characterized .The maximal activity (26.04 units/mg) of catalase is observed with chloroform buffer extraction. The kinetics of catalase; Michalis constant Km and maximum velocity Vmax is determined using Linweaver- Burk plot, The Km value for catalase (434.7mM), Vmax (100 m mole min -1). Characterization results demonstrate that the optimal pH for activity is (7.6). And the optimal temperature for activity is 30?C .The present study indicates that Banana peels is a good source of catalase enzyme.


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