Malate dehydrogenase from thermophilic Humicola lanuginosa and Mucor pusillus: purification and comparative properties of the enzymes with differing thermostabilities

1984 ◽  
Vol 62 (7) ◽  
pp. 559-565 ◽  
Author(s):  
Anupam S. Wali ◽  
Autar K. Mattoo
Keyword(s):  
Malate Dehydrogenase ◽  
Conformational Changes ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
The Other ◽  
Heat Inactivation ◽  
Ph Optimum ◽  
Molecular Weights ◽  
Other Hand ◽  
Humicola Lanuginosa

Malate dehydrogenase (L-malate:NAD+ oxidoreductase, EC 1.1.1.37) was purified from the thermophiles Humicola lanuginosa and Mucor pusillus. The H. lanuginosa enzyme was homogeneous on sodium dodecyl sulphate – polyacrylamide gels, while the M. pusillus enzyme was more than 95% pure. The two enzymes appeared to be composed of two subunits of equal size, each of 36 000 daltons (H. lanuginosa) or 33 000 daltons (M. pusillus). The native enzymes revealed molecular weights of 68 000 as determined by gel filtration. The isoelectric points of malate dehydrogenase from H. lanuginosa and M. pusillus were 3.9 and 4.2, respectively. The reduction of oxaloacetate by the H. lanuginosa enzyme was optimum at pH 8.5–9 with apparent Km's of 0.12 mM for oxaloacetate and 0.027 mM for NADH. On the other hand, M. pusillus enzyme snowed a pH optimum of 7.8–8.5 with apparent Km's of 0.075 mM for oxaloacetate and 0.1 mM for NADH. The L-malate oxidation reaction was catalyzed optimally at pH 10 by the H. lanuginosa enzyme with apparent Km's of 5.8 mM for malate and 0.1 mM for NAD, while the M. pusillus enzyme catalyzed it optimally between pH 9.5 and 10 with apparent Km's of 4.44 mM for malate and 0.16 mM for NAD. The optimum temperature for reduction of oxaloacetate was 50 °C for both the enzymes. The H. lanuginosa enzyme was resistant to heat inactivation at 40 °C, but lost 60% of its activity after 15 min at 50 °C. Mucor pusillus enzyme, on the other hand, retained 90% activity at 60 °C after 10 min. The two enzymes were protected from heat inactivation by monovalent cations (viz Na+, K+, and NH4+), as well as citrate, which may possibly involve conformational changes.

scholarly journals Characterization of an Inducible Chlorophenol O-Methyltransferase from Trichoderma longibrachiatum Involved in the Formation of Chloroanisoles and Determination of Its Role in Cork Taint of Wines

2003 ◽  
Vol 69 (9) ◽  
pp. 5089-5095 ◽  
Author(s):  
Juan-José R. Coque ◽  
María Luisa Álvarez-Rodríguez ◽  
Germán Larriba
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Competitive Inhibitor ◽  
Ph Optimum ◽  
Trichoderma Longibrachiatum ◽  
Molecular Weights ◽  
Apparent Homogeneity ◽  
Halogenated Phenols ◽  
Cork Taint

ABSTRACT A novel S-adenosyl-l-methionine (SAM)-dependent methyltransferase catalyzing the O methylation of several chlorophenols and other halogenated phenols was purified 220-fold to apparent homogeneity from mycelia of Trichoderma longibrachiatum CECT 20431. The enzyme could be identified in partially purified protein preparations by direct photolabeling with [methyl-3H]SAM, and this reaction was prevented by previous incubation with S-adenosylhomocysteine. Gel filtration indicated that the M r was 112,000, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme was composed of two subunits with molecular weights of approximately 52,500. The enzyme had a pH optimum between 8.2 and 8.5 and an optimum temperature of 28°C, with a pI of 4.9. The Km values for 2,4,6-trichlorophenol and SAM were 135.9 ± 12.8 and 284.1 ± 35.1 μM, respectively. S-Adenosylhomocysteine acted as a competitive inhibitor, with a Ki of 378.9 ± 45.4 μM. The methyltransferase was also strongly inhibited by low concentrations of several metal ions, such as Cu2+, Hg2+, Zn2+, and Ag+, and to a lesser extent by p-chloromercuribenzoic acid, but it was not significantly affected by several thiols or other thiol reagents. The methyltransferase was specifically induced by several chlorophenols, especially if they contained three or more chlorine atoms in their structures. Substrate specificity studies showed that the activity was also specific for halogenated phenols containing fluoro, chloro, or bromo substituents, whereas other hydroxylated compounds, such as hydroxylated benzoic acids, hydroxybenzaldehydes, phenol, 2-metoxyphenol, and dihydroxybenzene, were not methylated.

Functional Characterization of Four Thylakoid Membrane Polypeptides with Apparent Molecular Weights between 40 000 and 48 000

1978 ◽  
Vol 33 (3-4) ◽  
pp. 280-289 ◽  
Author(s):  
Wilhelm Menke ◽  
Friederike Koenig ◽  
Georg H. Schmid ◽  
Alfons Radunz
Keyword(s):  
Electron Donor ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
Functional Characterization ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Fluorescence Yield ◽  
Exchange Chromatography ◽  
The Other ◽  
Molecular Weights

Four polypeptides which exhibited apparent molecular weights from 40 000 to 48 000 were isolated from the thylakoid membrane. The isolation was achieved by gel filtration of polypeptides, solubilized by means of sodium dodecyl sulfate and, after removal of detergent by anion exchange chromatography in ethanolic solution. The polypeptide of the molecular weight 40000 was iden­tified as the y-component of the coupling factor of photophosphorylation via the effect of its antiserum and by its serological cross reactions. The antiserum not only inhibits photophosphory­lation reactions by 90% but also to the same extent the photoreduction of anthraquinone-2-sulfonate with tetramethyl benzidine as the electron donor, provided ADP, Pi and Mg2+ are present in the assay. The inhibition of electron transport is accompanied by a corresponding increase in the fluorescence yield. The other three antisera inhibit photosystem I reactions. In addition, the antiserum designated 45 000 PSI-1 inhibits phenazine methosulfate-mediated cyclic photophos­phorylation. This antiserum as well as the two other sera do not contain any detectable anti­coupling factor activity. Antiserum 45 000 PSI-4, in contrast to 45 000 PSI-1, does not inhibit cyclic photophosphorylation. Moreover, it is the only one of the four antisera which does not affect the ratio of the fluorescence yields measured at 735 and 685 nm (F 735/F 685) at 77 °K. Hence, the antigen 45 000 PSI-4 probably plays a role on the acceptor side of photosystem I. On the other hand, the antiserum 48 000 PSI-3 seems to exert its effect on the donor side of photosystem I, because it inhibits the photoreduction of anthraquinone-2-sulfonate with low con­centrations of the electron donor dichlorophenol indophenol. The prominent property of this anti­serum is that the photophosphorylation with fcrricyanide as the electron acceptor is stimulated more than two fold. This, however, it not accompanied by an apparent change of the electron flux between water and ferricyanide. The antiserum causes a decrease of fluorescence yield which is probably due to an increased energy spill-over. All antisera exert their activity only after an il­lumination of the chloroplast preparations for several minutes. The dosis-effect curve is hyperbolic for the antiserum 48 000 PSI-3 and is sigmoidal with the other three antisera.

scholarly journals OSMOTIC PRESSURE STUDY OF PROTEIN FRACTIONS IN NORMAL AND IN NEPHROTIC SUBJECTS

1939 ◽  
Vol 69 (6) ◽  
pp. 819-831 ◽  
Author(s):  
Jaques Bourdillon
Keyword(s):  
Osmotic Pressure ◽  
Normal Serum ◽  
The Other ◽  
Protein Fractions ◽  
Molecular Weights ◽  
Other Hand ◽  
Normal Albumin

In serum of patients with nephrosis both albumin and globulin showed by osmotic pressure nearly double the molecular weights of normal albumin and globulin. In the urines of such patients, on the other hand, both proteins showed molecular weights lower even than in normal serum. The colloidal osmotic pressures were measured by the author's method at such dilutions that the van't Hoff law relating pressures to molecular concentrations could be directly applied. For the albumin and globulin of normal serum the molecular weights found were 72,000 and 164,000 respectively, in agreement with the weights obtained by other methods.

Carboxymethylhydroxymuconic semialdehyde dehydrogenase in the 4-hydroxyphenylacetate catabolic pathway of Pseudomonas putida

1986 ◽  
Vol 64 (12) ◽  
pp. 1288-1293 ◽  
Author(s):  
Josefa M. Alonso ◽  
Amando Garrido-Pertierra
Keyword(s):  
Pseudomonas Putida ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Competitive Inhibitor ◽  
Catabolic Pathway ◽  
Ph Optimum ◽  
Semialdehyde Dehydrogenase ◽  
Standard Assay ◽  
Assay Conditions

5-Carboxymethyl-2-hydroxymuconic semialdehyde (CHMSA) dehydrogenase in the 4-hydroxyphenylacetate meta-cleavage pathway was purified from Pseudomonas putida by gel filtration, anion-exchange, and affinity chromatographies. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis analysis suggested an approximate tetrameric molecular weight of 200 000. The purified enzyme showed a pH optimum at 7.8. The temperature–activity relationship for the enzyme from 27 to 45 °C showed broken Arrhenius plots with an inflexion at 36–37 °C. Under standard assay conditions, the enzyme acted preferentially with NAD. It could also catalyze the reduction with NADP (which had a higher Km), at 18% of the rate observed for NAD. The following kinetic parameters were found: Km(NAD) = 20.0 ± 3.6 μM, Km(CHMSA) = 8.5 ± 1.8 μM, and Kd(enzyme–NAD complex) = 7.8 ± 2.0 μM. The product NADH acted as a competitive inhibitor against NAD.

scholarly journals Purification and Characterization of 2,6-β-d-Fructan 6-Levanbiohydrolase fromStreptomyces exfoliatus F3-2

2000 ◽  
Vol 66 (1) ◽  
pp. 252-256 ◽  
Author(s):  
Katsuichi Saito ◽  
Kazuya Kondo ◽  
Ichiro Kojima ◽  
Atsushi Yokota ◽  
Fusao Tomita
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Extracellular Enzyme ◽  
Molecular Weights ◽  
Sds Page ◽  
Monomeric Structure ◽  
Ph Range ◽  
Hydrolysis Of

ABSTRACT Streptomyces exfoliatus F3-2 produced an extracellular enzyme that converted levan, a β-2,6-linked fructan, into levanbiose. The enzyme was purified 50-fold from culture supernatant to give a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weights of this enzyme were 54,000 by SDS-PAGE and 60,000 by gel filtration, suggesting the monomeric structure of the enzyme. The isoelectric point of the enzyme was determined to be 4.7. The optimal pH and temperature of the enzyme for levan degradation were pH 5.5 and 60°C, respectively. The enzyme was stable in the pH range 3.5 to 8.0 and also up to 50°C. The enzyme gave levanbiose as a major degradation product from levan in an exo-acting manner. It was also found that this enzyme catalyzed hydrolysis of such fructooligosaccharides as 1-kestose, nystose, and 1-fructosylnystose by liberating fructose. Thus, this enzyme appeared to hydrolyze not only β-2,6-linkage of levan, but also β-2,1-linkage of fructooligosaccharides. From these data, the enzyme from S. exfoliatus F3-2 was identified as a novel 2,6-β-d-fructan 6-levanbiohydrolase (EC 3.2.1.64 ).

scholarly journals Characterization of proteins from the cytoskeleton of Giardia lamblia

1983 ◽  
Vol 59 (1) ◽  
pp. 81-103 ◽  
Author(s):  
R. Crossley ◽  
D.V. Holberton
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Giardia Lamblia ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Molecular Size ◽  
Molecular Weights

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.

Isomerization of Peroxidizing Thiadiazolidine Herbicides Is Catalyzed by Glutathione S-Transferase

1996 ◽  
Vol 51 (5-6) ◽  
pp. 342-354 ◽  
Author(s):  
Beate Nicolaus ◽  
Yukiharu Sato ◽  
Ko Wakabayashi ◽  
Peter Böger
Keyword(s):  
Protein Pattern ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Total Activity ◽  
Naphthalic Anhydride ◽  
Molecular Weights ◽  
Isomerase Activity ◽  
Ammonium Sulfate Precipitate ◽  
Catalyzed Reactions

Abstract Thiadiazolidine-converting activity (isomerase), detected in a 45-75% ammonium sulfate precipitate from corn seedlings extracts, was purified by chromatography on hydroxyapatite and by anion exchange on Mono Q Sepharose. Two fractions 1 and 2 with isomerase activity were separated on Mono Q by combination of a stepwise elution and continuous salt gradient; fraction 2 eluting at higher salt concentrations was found the most active. Total activity could be enhanced by treatment of seedlings with naphthalic anhydride. Both fractions containing isomerase activity were further purified by glutathione-(GSH) agarose affinity chromatography and characterized by their specificity for different thiadiazolidines. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration revealed that the isomerase of fraction 2 consists either of a homodimer or a heterodimer of two proteins with apparent molecular weights of 28 and 31 kDa, respectively. The protein pattern as well as the strict dependence of activity on thiol groups (GSH or dithiothreitol) suggested a glutathione Stransferase (GST) catalyzing the thiadiazolidine conversion. Further evidence was obtained by measuring reactions specific for GSTs in both purified fractions, namely the conjugating activity for l-chloro-2,4-dinitrobenzene (CDNB ). atrazine and metazachlor. While no atrazine turnover was found, metazachlor and CDNB conjugation occurred rapidly. Both fractions differed in their activities to several GST substrates with fraction 2 being more effective in metazachlor but less active in C DN B conjugation. Inhibitors specific for GST-catalyzed reactions also inhibited thiadiazolidine conversion confirming that isomerizing activity is attributed to a GST form. We conclude that GST isoforms with different affinities towards thiadiazolidines have been isolated. CDNB activity, molecular weight, the protein pattern on SDS-PAGE as well as the amino acid sequence of one of its polypeptides suggest that fraction 1, less active in thiadiazolidine isomerization, is identical to GST I. The second peptide of this fraction was resistant to Edman degradation probably due to N-terminal blockage. The properties of the high isomerase activity found in fraction 2 are in agreement with characteristics of a GST previously termed as isoform II.

SYNERGY OF TRANEXAMIC ACID AND FIBRIN IN THE ENHANCEMENT OF THE ACTIVATION OF GLU-PLASMINOGEN BY UROKINASE

1987 ◽  
Author(s):  
Y Sugawara ◽  
Y Takada ◽  
A Takada
Keyword(s):  
Tranexamic Acid ◽  
Conformational Changes ◽  
The Other ◽  
Catalytic Rate Constant ◽  
Kringle 5 ◽  
Other Hand ◽  
Activation Rate ◽  
The Uk ◽  
Similar Kinetic ◽  
Plateau Level

The activation rate of Glu-plasminogen (Glu-plg) by urokinase (UK) was enhanced in the presence of either tranexamic acid or fibrin with increase in catalytic rate constant (kcat) without change in Km. The values of kcat increased almost linearly up to 0.5 mM of tranexamic acid concentration and reached a plateau. On the other hand, the presence of increasing concentrations of fibrin resulted in almost hyperbolic increase in kcat values, reaching the plateau level at 0.04 μM. The values of kcat increased three fold at 0.5 mM of tranexamic acid and at 0.04 μM of fibrin. Fibrinogen was less effective and kcat increased two fold in the presence of 1 μM of fibrinogen. Similar kinetic parameters suggest that basic mechanisms underlying the enhanced activation of Glu-plg by UK may be similar between in the presence of tranexamic acid and fibrin. Possibly conformational changes of Glu-plg upon interaction of its lysine binding sites (LBS)< with tranexamic acid or fibrin may be reasons for the enhanced activation. The addition of fibrin to 1 mM tranexamic acid resulted in further increase in kcat of the UK activation of Glu-plg. On the other hand, the addition of tranexamic acid to 0.1 μM of fibrin further increased kcat of the UK activation of Glu-plg. Thus synergy was observed in the activation of Glu-plg by UK between tranexamic acid and fibrin. Fibrin binding site on kringle 5 of Glu-plg may be involved in further increase in the activation rate of Glu-plg by UK in the presence of both fibrin and tranexamic acid in comparison to that in the presence of tranexamic acid alone. Possibly, Glu-plg bound with both tranexamic acid and fibrin (at kringle 5) may be most effectively activated by UK. From the concentrations of fibrin to show 50 % changes of kcat, it is also suggested that two molecules of Glu-plg should bind to one molecule of fibrin monomer.

scholarly journals Purification and characterization of two human erythrocyte arylamidases preferentially hydrolysing N-terminal arginine or lysine residues

1978 ◽  
Vol 175 (3) ◽  
pp. 1051-1067 ◽  
Author(s):  
K K Mäkinen ◽  
P L Mäkinen
Keyword(s):  
Substrate Inhibition ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Gel Permeation Chromatography ◽  
Ph Optimum ◽  
Preparative Scale ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Lysine Residues ◽  
Enzyme I

Two arylamidases (I and II) were purified from human erythrocytes by a procedure that comprised removal of haemoglobin from disrupted cells with CM-Sephadex D-50, followed by treatment of the haemoglobin-free preparation subsequently with DEAE-cellulose, gel-permeation chromatography on Sephadex G-200, gradient solubilization on Celite, isoelectric focusing in a pH gradient from 4 to 6, gel-permeation chromatography on Sephadex G-100 (superfine), and finally affinity chromatography on Sepharose 4B covalently coupled to L-arginine. In preparative-scale purifications, enzymes I and II were separated at the second gel-permeation chromatography. Enzyme II was obtained as a homogeneous protein, as shown by several criteria. Enzyme I hydrolysed, with decreasing rates, the L-amino acid 2-naphtylamides of lysine, arginine, alanine, methionine, phenylalanine and leucine, and the reactions were slightly inhibited by 0.2 M-NaCl. Enzyme II hydrolysed most rapidly the corresponding derivatives of arginine, leucine, valine, methionine, proline and alanine, in that order, and the hydrolyses were strongly dependent on Cl-. The hydrolysis of these substrates proceeded rapidly at physiological Cl- concentration (0.15 M). The molecular weights (by gel filtration) of enzymes I and II were 85 000 and 52 500 respectively. The pH optimum was approx. 7.2 for both enzymes. The isoelectric point of enzyme II was approx. 4.8. Enzyme I was activated by Co2+, which did not affect enzyme II to any noticeable extent. The kinetics of reactions catalysed by enzyme I were characterized by strong substrate inhibition, but enzyme II was not inhibited by high substrate concentrations. The Cl- activated enzyme II also showed endopeptidase activity in hydrolysing bradykinin.

scholarly journals Purification, characterization and inhibition of human skin collagenase

1978 ◽  
Vol 169 (2) ◽  
pp. 265-276 ◽  
Author(s):  
David E. Woolley ◽  
Robert W. Glanville ◽  
Dennis R. Roberts ◽  
John M. Evanson
Keyword(s):  
Human Skin ◽  
Culture Medium ◽  
Serum Proteins ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Polyacrylamide Gel ◽  
Collagen Fibrils ◽  
Ph Optimum

1. The neutral collagenase released into the culture medium by explants of human skin tissue was purified by ultrafiltration and column chromatography. The final enzyme preparation had a specific activity against thermally reconstituted collagen fibrils of 32μg of collagen degraded/min per mg of enzyme protein, representing a 266-fold increase over that of the culture medium. Electrophoresis in polyacrylamide disc gels showed it to migrate as a single protein band from which enzyme activity could be eluted. Chromatographic and polyacrylamide-gel-elution experiments provided no evidence for the existence of more than one active collagenase. 2. The molecular weight of the enzyme estimated from gel filtration and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis was approx. 60000. The purified collagenase, having a pH optimum of 7.5–8.5, did not hydrolyse the synthetic collagen peptide 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-d-Arg-OH and had no non-specific proteinase activity when examined against non-collagenous proteins. 3. It attacked undenatured collagen in solution at 25°C, producing the two characteristic products TCA(¾) and TCB(¼). Collagen types I, II and III were all cleaved in a similar manner by the enzyme at 25°C, but under similar conditions basement-membrane collagen appeared not to be susceptible to collagenase attack. At 37°C the enzyme attacked gelatin, producing initially three-quarter and one-quarter fragments of the α-chains, which were degraded further at a lower rate. As judged by the release of soluble hydroxyproline peptides and electron microscopy, the purified enzyme degraded insoluble collagen derived from human skin at 37°C, but at a rate much lower than that for reconstituted collagen fibrils. 4. Inhibition of the skin collagenase was obtained with EDTA, 1,10-phenanthroline, cysteine, dithiothreitol and sodium aurothiomaleate. Cartilage proteoglycans did not inhibit the enzyme. The serum proteins α2-macroglobulin and β1-anti-collagenase both inhibited the enzyme, but α1-anti-trypsin did not. 5. The physicochemical and enzymic properties of the skin enzyme are discussed in relation to those of other human collagenases.

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