scholarly journals Purification and characterization of a new endoglucanase from Clostridium thermocellum

1992 ◽  
Vol 283 (1) ◽  
pp. 69-73 ◽  
Author(s):  
M P M Romaniec ◽  
U Fauth ◽  
T Kobayashi ◽  
N S Huskisson ◽  
P J Barker ◽  
...  

An endoglucanase (1,4-beta-D-glucan glucanohydrolase, EC 3.2.1.4) from the thermophilic anaerobe Clostridium thermocellum was purified to apparent homogeneity without the use of denaturants. No carbohydrate is associated with the endoglucanase. A molecular mass of 76,000 Da was determined by SDS/PAGE. The optimal pH is 7.0 and the enzyme is isoelectric at pH 5.05. The enzyme has a temperature optimum of 70 degrees C and retains approx. 50% of its activity after 48 h at 60 degrees C. Hydrolysis of CM-cellulose takes place with a rapid decrease in viscosity but a slow liberation of reducing sugars, indicating an endoglucanase type of activity. The endoglucanase shows little ability to hydrolyse highly ordered cellulose. Cellobiose inhibits whereas Mg2+ and Ca2+ stimulate the activity. The enzyme is completely inactivated by 1 mM-Hg2+ and is inhibited by a thiol-blocking reagent.

1996 ◽  
Vol 316 (3) ◽  
pp. 841-846 ◽  
Author(s):  
Stuart M. PITSON ◽  
Robert J. SEVIOUR ◽  
Barbara M. McDOUGALL ◽  
Bruce A. STONE ◽  
Maruse SADEK

An endo-(1 → 6)-β-glucanase has been isolated from the culture filtrates of the filamentous fungus Acremonium persicinum and purified by (NH4)2SO4 precipitation followed by anion-exchange and gel-filtration chromatography. SDS/PAGE of the purified enzyme gave a single band with an apparent molecular mass of 42.7 kDa. The enzyme is a non-glycosylated, monomeric protein with a pI of 4.9 and pH optimum of 5.0. It hydrolysed (1 → 6)-β-glucans (pustulan and lutean), initially yielding a series of (1 → 6)-β-linked oligoglucosides, consistent with endo-hydrolytic action. Final hydrolysis products from these substrates were gentiobiose and gentiotriose, with all products released as β-anomers, indicating that the enzyme acts with retention of configuration. The purified enzyme also hydrolysed Eisenia bicyclis laminarin, liberating glucose, gentiobiose, and a range of larger oligoglucosides, through the apparent hydrolysis of (1 → 6)-β- and some (1 → 3)-β-linkages in this substrate. Km values for pustulan, lutean and laminarin were 1.28, 1.38, and 1.67 mg/ml respectively. The enzyme was inhibited by N-acetylimidazole, N-bromosuccinimide, dicyclohexylcarbodi-imide, Woodward's Regent K, 2-hydroxy-5-nitrobenzyl bromide, KMnO4 and some metal ions, whereas D-glucono-1,5-lactone and EDTA had no effect.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Imran Ali ◽  
Ali Akbar ◽  
Mohammad Anwar ◽  
Sehanat Prasongsuk ◽  
Pongtharin Lotrakul ◽  
...  

An extracellularα-amylase from the obligate halophilicAspergillus penicillioidesTISTR3639 strain was produced and enriched to apparent homogeneity by ammonium sulfate precipitation and Sephadex G100 gel filtration column chromatography. The mass of the purified amylase was estimated to be 42 kDa by SDS-PAGE. With soluble starch as the substrate it had a specific activity of 118.42 U·mg−1andVmax⁡andKmvalues of 1.05 µmol·min−1·mg−1and 5.41 mg·mL−1, respectively. The enzyme was found to have certain polyextremophilic characteristics, with an optimum activity at pH 9, 80°C, and 300 g·L−1NaCl. The addition of CaCl2at 2 mM was found to slightly enhance the amylase activity, while ZnCl2, FeCl2, or EDTA at 2 mM was strongly or moderately inhibitory, respectively, suggesting the requirement for a (non-Fe2+or Zn2+) divalent cation. The enzyme retained more than 80% of its activity when incubated with three different laundry detergents and had a better performance compared to a commercial amylase and three detergents in the presence of increasing NaCl concentrations up to 300 g·L−1. Accordingly, it has a good potential for use as anα-amylase in a low water activity (high salt concentration) and at high pH and temperatures.


1992 ◽  
Vol 288 (2) ◽  
pp. 637-642 ◽  
Author(s):  
N Divecha ◽  
C E L Brooksbank ◽  
R F Irvine

We detail the purification and characterization of three distinct isoforms of PtdIns4P 5-kinase present in bovine brain. One of these, PtdIns4P 5-kinase C, was purified to apparent homogeneity, and SDS/PAGE analysis demonstrated a single polypeptide and molecular mass 53 KDa. These three isoforms were shown to differ in their kinetic properties, and immunological characterization with an antibody raised to PtdIns4P 5-kinase C demonstrated that this isoform was unrelated to the other two. Furthermore, PtdIns4P 5-kinase C was shown to be the bovine brain homologue of the Type II PtdIns4P 5-kinase previously purified from human erythrocytes [Bazenet, Ruano, Brockman & Anderson (1990) J. Biol. Chem. 265, 18012-18022].


1999 ◽  
Vol 30 (2) ◽  
pp. 114-119 ◽  
Author(s):  
Claudio Henrique Cerri e Silva ◽  
Jurgen Puls ◽  
Marcelo Valle de Sousa ◽  
Edivaldo Ximenes Ferreira Filho

A xylan-degrading enzyme (xylanase II) was purified to apparent homogeneity from solid-state cultures of Aspergillus fumigatus Fresenius. The molecular weight of xylanase II was found to be 19 and 8.5 kDa, as estimated by SDS-PAGE and gel filtration on FPLC, respectively. The purified enzyme was most active at 55 °C and pH 5.5. It was specific to xylan. The apparent Km and Vmax values on soluble and insoluble xylans from oat spelt and birchwood showed that xylanase II was most active on soluble birchwood xylan. Studies on hydrolysis products of various xylans and xylooligomers by xylanase II on HPLC showed that the enzyme released a range of products from xylobiose to xylohexaose, with a small amount of xylose from xylooligomers, and presented transferase activity.


1980 ◽  
Vol 7 (2) ◽  
pp. 131 ◽  
Author(s):  
JB Caldwell ◽  
LG Sparrow

An aminopeptidase with specificity for N-terminal glutamic and aspartic acid residues has been purified to apparent homogeneity from pea seeds (Pisum sativum cv. Greenfeast). It also catalyses the hydrolysis of the glutaryl-phenylalanine bond of the synthetic chymotrypsin substrate glutaryl- L-phenylalanine p-nitroanilide. The native enzyme, which has a molecular weight of approximately 500 000, gives a single band on polyacrylamide gel electrophoresis but two major bands when subjected to electrophoresis in the presence of sodium dodecyl sulfate after reduction. Its behaviour with various inhibitors suggests that a sulfhydryl group is important for its activity.


1992 ◽  
Vol 281 (1) ◽  
pp. 231-237 ◽  
Author(s):  
J F Aparicio ◽  
C Hardisson ◽  
J Sánchez

Streptomyces glaucescens has a DNAase whose synthesis is under nutritional control. We have purified this enzyme to apparent homogeneity by phosphocellulose chromatography followed by heparin-agarose, Cibacron Blue F3-GA-Sepharose and Sephadex G-75 chromatography and MonoQ f.p.l.c. The enzyme had an apparent Mr of 39,600 and a pI of approx. 8.15. The Mr of the native enzyme estimated by gel chromatography was 49,000. The DNAase had a pH optimum of 7.5 and an absolute requirement for bivalent cations in the reaction buffer. It was inhibited by high salt concentrations, chelating agents or phosphate-containing compounds and was stimulated by dimethyl sulphoxide. The activity was greatly diminished unless dithiothreitol or 2-mercaptoethanol was included in the reaction mixture. Reagents such as Hg2+ or iodoacetate strongly inhibited the enzyme. The nuclease hydrolysed both double-stranded and single-stranded DNA, showing greater affinity for double-stranded DNA, and no detectable hydrolysis of RNA. The enzyme produced nicks in double-stranded DNA, generating 3′-hydroxy and 5′-phosphate termini, and degraded circular DNA.


1995 ◽  
Vol 309 (1) ◽  
pp. 315-320 ◽  
Author(s):  
R H Palmer ◽  
P J Parker

The recently described protein kinase C-related kinase (PRK) family is comprised of at least three members: PRK1, PRK2 and PRK3. Here the expression, purification and characterization of the ubiquitously expressed isoform, PRK1, is described. The enzyme was expressed in COS 7 cells and subsequently purified to apparent homogeneity by sequential column chromatography. The purified PRK1 protein migrates as a single 120 kDa polypeptide on SDS/PAGE. It displays a substrate specificity that in part resembles that of protein kinase C (PKC); however, unlike PKC, it is not activated by any combination of phorbol esters, diacylglycerol and Ca2+. Nevertheless, it can be activated by limited proteolysis, indicating a negative regulatory role for the N-terminal domain(s). PRK1 is also activated by phospholipids. The physiological relevance of this activation is discussed.


Crustaceana ◽  
2015 ◽  
Vol 88 (3) ◽  
pp. 259-272 ◽  
Author(s):  
X. W. Xiang ◽  
Y. F. Zhou ◽  
Y. B. Hao ◽  
H. C. Yang ◽  
H. W. Ma ◽  
...  

Polyphenoloxidase (PPO) from Solenocera crassicornis (H. Milne Edwards, 1837) was partially purified through ion-exchange and gel-filtration chromatography, and its enzymatic properties were also characterized using l-dihydroxyphenylalanine (L-DOPA) as the specific substrate. The molecular mass of PPO in SDS-PAGE is about 66.5 kDa, and the PPO molecule isolated by HPLC, is 133 kDa, implying it is a homodimeric protein. The optimal pH and temperature of PPO activity was 6.5 and 40°C, and the value was 3.80 and 8.12 on L-DOPA and on catechol, respectively. It was found that the purified PPO could only catalyse o-diphenol substrates, inferring that it belongs to the catechol-oxidase family. The PPO was very sensitive to phenylthiourea, ascorbic acid, citric acid and cysteine. The PPO activity was strongly inhibited by ethylenediaminetetraacetic acid (EDTA), Cu2+ and Zn2+, indicating that Solenocera crassicornis PPO is most probably a copper-containing metalloenzyme.


2021 ◽  
Vol 85 (3) ◽  
pp. 600-610
Author(s):  
Akihiro Fujita ◽  
Akira Kawashima ◽  
Yuuki Mitsukawa ◽  
Noriaki Kitagawa ◽  
Hikaru Watanabe ◽  
...  

ABSTRACT Glucanotransferases that can synthesize cyclo-{→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→} (CI4) from dextran were purified to homogeneity from the culture supernatant of Agreia sp. D1110 and Microbacterium trichothecenolyticum D2006. The molecular mass of both enzymes was estimated to be 86 kDa by SDS-PAGE. The glucanotransferase, named CI4-forming enzyme, from Agreia sp. exhibited the highest activity at pH 6.0 and 40 °C. The enzyme was stable on the pH range of 4.6-9.9 and up to 40 °C. On the other hand, the enzyme from M. trichothecenolyticum exhibited the highest activity at pH 5.7 and 40 °C. The enzyme was stable on the pH range of 5.0-6.9 and up to 35 °C. Both enzymes catalyzed 4 reactions, namely, intramolecular α-1,6-transglycosylation (cyclization), intermolecular α-1,6-transglycosylation, hydrolysis of CI4, and coupling reaction. Furthermore, the CI4-forming enzyme produced CI4 from α-1,6-linked glucan synthesized from starch by 6-α-glucosyltransferase. These findings will enable the production of CI4 from starch.


Parasitology ◽  
1992 ◽  
Vol 105 (2) ◽  
pp. 211-218 ◽  
Author(s):  
C. Chavez-Olortegui ◽  
M. Resende ◽  
C. A. P. Tavares

SUMMARYFractionation of Schistosoma mansoni cercariae gland secretion on a Sephadex G-150 column followed by a Superose-12 column in an FPLC system, isolated a 47 kDa protease which migrated as a single band on SDS–PAGE gels. A monoclonal antibody (MAb) was produced which recognizes only the 47 kDa protease, and an immuno-affinity column with the MAb was used to isolate the protease. The 47 kDa protease showed activity on several macromolecules such as elastin and collagen type VI besides gelatin and casein. This suggests that this enzyme can be one of the enzymes that might facilitate invasion of the cercariae through host skin. The optimal pH of the protease against the synthetic substrate, Ac-Phe-Arg-Nan, in Tris–HCI buffer was 10. Experiments with protease inhibitors indicate that the purified enzyme is a serine protease.


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