scholarly journals Trichomonas vaginalis: characterization of ornithine decarboxylase

1993 ◽  
Vol 293 (2) ◽  
pp. 487-493 ◽  
Author(s):  
N Yarlett ◽  
B Goldberg ◽  
M A Moharrami ◽  
C J Bacchi
Keyword(s):  
Ornithine Decarboxylase ◽  
Trichomonas Vaginalis ◽  
Gel Filtration ◽  
Kinetic Properties ◽  
Ph Optimum ◽  
Polyamine Biosynthesis ◽  
Arginine Dihydrolase ◽  
Sds Page ◽  
A Subunit

Ornithine decarboxylase (ODC), the lead enzyme in polyamine biosynthesis, was partially purified from Trichomonas vaginalis and its kinetic properties were studied. The enzyme appears to be of special significance in this anaerobic parasite, since the arginine dihydrolase pathway generates ATP as well as putrescine from arginine. ODC from T. vaginalis had a broad substrate specificity, decarboxylating ornithine (100%), lysine (1.0%) and arginine (0.1%). The enzyme had a pH optimum of 6.5, a temperature optimum of 37 degrees C and was pyridoxal 5′-phosphate-dependent. Attempts to separate ornithine- from lysine-decarboxylating activity by thermal-stability and pH-optima curves were not successful. Although Km values for ornithine and lysine were 109 and 91 microM respectively, and the Vmax values for these substrates were 1282 and 13 nmol/min per mg of protein respectively, the most important intracellular substrate is ornithine, since intracellular ornithine levels are 3.5 times those of lysine and extracellular putrescine levels are 7.5 times those of cadaverine. Ornithine was also an effective inhibitor of lysine-decarboxylating activity (Ki 150 microM), whereas lysine was relatively ineffective as inhibitor of ornithine-decarboxylating activity (Ki 14.5 mM). Crude ODC activity was localized (86%) in the 43,000 g supernatant and 3303-fold purification was obtained by (NH4)2SO4 salting and DEAE-Sephacel, agarose-gel and hydroxyapatite chromatography steps. The enzyme bound difluoro[3H]methylornithine ([3H]DFMO) with a ratio of drug bound to activity of 2500 fmol/unit, where 1 unit corresponds to 1 nmol of CO2 released from ornithine/min. The enzyme had a native M(r) of 210000 (gel filtration), with a subunit M(r) of 55,000 (by SDS/PAGE), suggesting that the trichomonad enzyme is a tetramer. From the subunit M(r) and binding ratio of DFMO, there is about 137 ng of ODC per mg of T. vaginalis protein (0.013%). The significant amount of ODC protein present supports the view that putrescine synthesis in T. vaginalis plays an important role in the metabolism of the parasite.

scholarly journals Purification and characterization of cytosolic pyruvate kinase from banana fruit

2000 ◽  
Vol 352 (3) ◽  
pp. 875-882 ◽  
Author(s):  
William L. TURNER ◽  
William C. PLAXTON
Keyword(s):  
Pyruvate Kinase ◽  
Specific Activity ◽  
Gel Filtration ◽  
Banana Fruit ◽  
Ph Optimum ◽  
Cytosolic Ph ◽  
Pep Carboxylase ◽  
Sds Page ◽  
Optimal Efficiency

Cytosolic pyruvate kinase (PKc) from ripened banana (Musa cavendishii L.) fruits has been purified 543-fold to electrophoretic homogeneity and a final specific activity of 59.7µmol of pyruvate produced/min per mg of protein. SDS/PAGE and gel-filtration FPLC of the final preparation indicated that this enzyme exists as a 240kDa homotetramer composed of subunits of 57kDa. Although the enzyme displayed a pH optimum of 6.9, optimal efficiency in substrate utilization [in terms of Vmax/Km for phosphoenolpyruvate (PEP) or ADP] was equivalent at pH6.9 and 7.5. PKc activity was absolutely dependent upon the presence of a bivalent and a univalent cation, with Mg2+ and K+ respectively fulfilling this requirement. Hyperbolic saturation kinetics were observed for the binding of PEP, ADP, Mg2+ and K+ (Km values of 0.098, 0.12, 0.27 and 0.91mM respectively). Although the enzyme utilized UDP, IDP, GDP and CDP as alternative nucleotides, ADP was the preferred substrate. L-Glutamate and MgATP were the most effective inhibitors, whereas L-aspartate functioned as an activator by reversing the inhibition of PKc by L-glutamate. The allosteric features of banana PKc are compared with those of banana PEP carboxylase [Law and Plaxton (1995) Biochem. J. 307, 807Ő816]. A model is presented which highlights the roles of cytosolic pH, MgATP, L-glutamate and L-aspartate in the co-ordinate control of the PEP branchpoint in ripening bananas.

scholarly journals Purification and characterization of three extracellular (1→3)-β-d-glucan glucohydrolases from the filamentous fungus Acremonium persicinum

1995 ◽  
Vol 308 (3) ◽  
pp. 733-741 ◽  
Author(s):  
S M Pitson ◽  
R J Seviour ◽  
B M McDougall ◽  
J R Woodward ◽  
B A Stone
Keyword(s):  
Filamentous Fungus ◽  
Gel Filtration ◽  
High Specificity ◽  
Major Product ◽  
Ph Optimum ◽  
Sds Page ◽  
Molecular Masses ◽  
Monomeric Proteins ◽  
Ph Range

Three (1-->3)-beta-D-glucanases (GNs) were 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. Homogeneity of the purified proteins was confirmed by SDS/PAGE, isoelectric focusing and N-terminal amino acid sequencing. All three GNs (GN I, II and III) are non-glycosylated, monomeric proteins with apparent molecular masses, estimated by SDS/PAGE, of 81, 85 and 89 kDa respectively. pI values for the three enzymes are 5.3, 5.1, and 4.4 respectively. The pH optimum for GN I is 6.5, and 5.0 for GN II and III. All three purified enzymes displayed stability over the pH range 4.5-10.0. Optimum activities for GN I, II and III were recorded at 65, 55 and 60 degrees C respectively, with both GN II and III having short-term stability up to 50 degrees C and GN I up to 55 degrees C. The purified GNs have high specificity for (1-->3)-beta-linkages and hydrolysed a range of (1-->3)-beta- and (1-->3)(1-->6)-beta-D-glucans, with laminarin from Laminaria digitata being the most rapidly hydrolysed substrate of those tested. K(m) values for GN I, II, and III against L. digitata laminarin were 0.1, 0.23 and 0.22 mg/ml respectively. D-Glucono-1,5-lactone does not inhibit any of the three GNs, some metals ions are mild inhibitors, and N-bromosuccinimide and KMnO4 are strong inhibitors. All three GNs acted in an exo-hydrolytic manner, determined by the release of alpha-glucose as the initial and major product of hydrolysis of (1-->3)-beta-D-glucans, and confirmed by viscometric analysis and the inability to cleave periodate-oxidized laminarin, and may be classified as (1-->3)-beta-D-glucan glucohydrolases (EC 3.2.1.58).

scholarly journals Purification and characterization of an extracellular (1 → 6)-β-glucanase from the filamentous fungus Acremonium persicinum

1996 ◽  
Vol 316 (3) ◽  
pp. 841-846 ◽  
Author(s):  
Stuart M. PITSON ◽  
Robert J. SEVIOUR ◽  
Barbara M. McDOUGALL ◽  
Bruce A. STONE ◽  
Maruse SADEK
Keyword(s):  
Molecular Mass ◽  
Filamentous Fungus ◽  
Gel Filtration ◽  
Purification And Characterization ◽  
Eisenia Bicyclis ◽  
Ph Optimum ◽  
Hydrolysis Products ◽  
Sds Page ◽  
Hydrolysis Of

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.

scholarly journals Characterization of the hydroxymethylglutaryl-CoA lyase precursor, a protein targeted to peroxisomes and mitochondria

1996 ◽  
Vol 315 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Lyudmila I. ASHMARINA ◽  
Marie-France ROBERT ◽  
Marc-André ELSLIGER ◽  
Grant A. MITCHELL
Keyword(s):  
Molecular Mass ◽  
Gel Filtration ◽  
Leader Peptide ◽  
Mitochondrial Targeting ◽  
Ph Optimum ◽  
Sds Page ◽  
Peroxisomal Targeting ◽  
Quaternary Structures ◽  
Hydroxymethylglutaryl Coa Lyase

We previously showed that human liver hydroxymethylglutaryl-CoA (HMG-CoA) lyase (HL; EC 4.1.3.4) is found in both mitochondria and peroxisomes. HL contains a 27-residue N-terminal mitochondrial targeting sequence which is cleaved on mitochondrial entry, as well as a C-terminal Cys-Lys-Leu peroxisomal targeting motif. Because peroxisomal HL has a greater molecular mass and more basic pI value than mitochondrial HL, we predicted that peroxisomal HL retains the mitochondrial leader. To test this hypothesis, we expressed both the precursor (pHL) and mature (mHL) peptides in Escherichia coli and studied their properties. pHL purified by ion-exchange and hydrophobic chromatography had a pI of 7.6 on FPLC chromatofocusing and a molecular mass of 34.5 kDa on SDS/PAGE, similar to our findings for peroxisomal HL. For purified mHL, pI (6.2) and molecular mass (32 kDa) values resemble those of mitochondrial HL. Purified pHL is similar to mHL in Km for HMG-CoA (44.8 μM), kcat (6.3 min-1) and pH optimum (9.0–9.5). However, the quaternary structures of pHL and mHL differ. On Superose 12 FPLC gel filtration and also on ultrafiltration, both in the presence and in the absence of HMG-CoA, pHL behaves as a monomer whereas mHL migrates as a dimer. We conclude that the HL precursor is probably identical to peroxisomal HL, that its catalytic properties resemble those of mature mitochondrial HL, and that the mitochondrial leader peptide prevents dimerization of pHL.

scholarly journals Characterization of 6-phosphofructo-2-kinase from foetal-rat liver

1992 ◽  
Vol 281 (2) ◽  
pp. 457-463 ◽  
Author(s):  
P Martín-Sanz ◽  
M Cascales ◽  
L Boscá
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Gel Filtration ◽  
Kinetic Properties ◽  
Dependent Protein Kinase ◽  
Kinase C ◽  
Sds Page ◽  
Dependent Protein ◽  
Molecular Masses

Foetal and adult liver 6-phosphofructo-2-kinase (PFK-2) were purified by identical protocols. The native molecular masses of both enzymes were determined by gel filtration and were 89.1 and 100.0 kDa respectively. No differences were found in SDS/PAGE in 10%-acrylamide gel (55 kDa per subunit). The kinetic properties displayed by both enzymes were similar, except for the sensitivity to inhibition by sn-glycerol 3-phosphate. Foetal PFK-2 was a good substrate for phosphorylation by cyclic AMP-dependent protein kinase and protein kinase C, whereas the adult enzyme was phosphorylated only by cyclic AMP-dependent protein kinase. However, the phosphorylation affected only the kinetic properties of the adult enzyme, suggesting the presence in both enzymes of different sites of phosphorylation by cyclic AMP-dependent protein kinase. These differences in primary structure were consistent with the distinct chromatographic profiles of the phosphopeptides after digestion of the protein with CNBr. Western-blot analysis with antibodies specific for the N-terminal region of the liver-type PFK-2 poorly recognized the foetal enzyme, suggesting that both enzymes differ at least in the N-terminal sequence.

scholarly journals Isolation and partial characterization of protease from Pseudomonas aeruginosa ATCC 27853

2010 ◽  
Vol 75 (8) ◽  
pp. 1041-1052 ◽  
Author(s):  
Lidija Izrael-Zivkovic ◽  
Gordana Gojgic-Cvijovic ◽  
Ivanka Karadzic
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Molecular Mass ◽  
Gel Filtration ◽  
Zinc Ion ◽  
Metal Chelators ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sds Page ◽  
Potential Use

Enzymatic characteristics of a protease from medically important, referent strain of Pseudomonas aeruginosa ATCC 27853 were determined. According to SDS PAGE and gel filtration it was estimated that molecular mass of the purified enzyme was about 15 kDa. Other enzymatic properties were found to be: pH optimum 7.1, pH stability between pH 6.5 and pH 10; temperature optimum around 60?C while the enzyme was stable at 60?C for 30 min. The inhibition of the enzyme was observed with the metal chelators such as EDTA and 1,10- phenanthroline, suggesting that the protease is a metalloenzyme. Further more it was determined that enzyme contains one mole of zinc ion per mole of enzyme. The protease is stable in the presence of different organic solvents, which enable potential use for synthesis of peptides.

scholarly journals Panagrellus redivivus ornithine decarboxylase: structure of the gene, expression in Escherichia coli and characterization of the recombinant protein

1996 ◽  
Vol 317 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Gabriele NIEMANN ◽  
Hans von BESSER ◽  
Rolf D. WALTER
Keyword(s):  
Ornithine Decarboxylase ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Single Copy ◽  
Ecori Fragment ◽  
Nucleotide Sequence Analysis ◽  
Panagrellus Redivivus ◽  
Sds Page ◽  
Km Value

A Southern blot analysis of the Panagrellus redivivus ornithine decarboxylase (ODC) gene suggests that it is a single-copy gene that resides on a genomic 3.2 kb EcoRI fragment. Phage clones possessing ODC gene sequences were isolated from a genomic EMBL-4 library and purified. The phage DNA inserts were analysed and a 3.2 kb EcoRI fragment containing the entire ODC gene was isolated. The nucleotide sequence analysis of this fragment reveals that the gene is interrupted by two introns of 47 and 49 bp. In the 5´ non-translated region of the gene, putative AP1, VPE2 and c-Myc binding sites were identified. The ODC cDNA was expressed in a bacterial system as a His-fusion protein and the enzyme was purified by Ni2+-chelating affinity chromatography. The subunit molecular mass, as deduced from the cDNA and shown by SDS/PAGE, is 47.1 kDa. On the basis of gel filtration analyses it is shown that the active enzyme is a dimer. The specific enzyme activity was determined to be 4.2 μmol CO2/min/mg protein. The enzyme is dependent on pyridoxal 5-phosphate as a cofactor, and the presence of dithioerythritol or other thiol-reducing agents is essential for maximal activity. The Km value for l-ornithine was determined as 44 μM. The Ki values for putrescine, α-difluoromethylornithine, α-hydrazino-ornithine and α-methylornithine were calculated as 51, 34, 0.34 and 42 μM respectively.

scholarly journals Purification and characterization of cysteine-S-conjugate N-acetyltransferase from pig kidney

1996 ◽  
Vol 317 (1) ◽  
pp. 213-218 ◽  
Author(s):  
Achim AIGNER ◽  
Martina JÄGER ◽  
Ralf PASTERNACK ◽  
Peter WEBER ◽  
Dirk WIENKE ◽  
...  
Keyword(s):  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Gel Filtration ◽  
Protein Band ◽  
Exchange Chromatography ◽  
Polyclonal Antiserum ◽  
Partial Purification ◽  
Ph Optimum ◽  
Sds Page

Microsomal cysteine-S-conjugate N-acetyltransferase catalyses the N-acetylation of various S-substituted cysteines in liver and kidney. We describe here the purification and more detailed characterization of this enzyme catalysing the final reaction of mercapturic acid biosynthesis, and thus playing a crucial role in the detoxicating metabolism of many xenobiotics. The solubilization of cysteine-S-conjugate N-acetyltransferase by deoxy-BIGCHAP [N,N´-bis-(3-d-gluconamidopropyl)deoxycholamide] was the prerequisite for partial purification by means of anion-exchange chromatography. The molecular mass of the enzyme was determined by gel filtration. A polyclonal antiserum was raised against the excised protein band from SDS/PAGE and purified antibodies were used for the complete purification of native cysteine-S-conjugate N-acetyltransferase by immunoaffinity chromatography. A dimeric form of the enzyme was sometimes detected on SDS/PAGE, depending on the degree of purification. For further characterization of cysteine-S-conjugate N-acetyltransferase, the stability of catalytic activity, the pH optimum and Km values were determined. The inhibitory effects of various agents were tested, revealing a substantial, yet not complete, loss of cysteine-S-conjugate N-acetyltransferase activity after treatment with cysteine proteinase inhibitors or probenecid under various conditions.

Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Ph Optimum ◽  
Isolation And Characterization ◽  
Ph Range ◽  
Inhibition Studies ◽  
Final Purification

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.

scholarly journals Identification and characterization of Sulfolobus solfataricusD-gluconate dehydratase: a key enzyme in the non-phosphorylated Entner–Doudoroff pathway

2005 ◽  
Vol 387 (1) ◽  
pp. 271-280 ◽  
Author(s):  
Seonghun KIM ◽  
Sun Bok LEE
Keyword(s):  
Molecular Mass ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Genome Database ◽  
Sds Page ◽  
Key Enzyme ◽  
Bivalent Metal Ions ◽  
Ammonium Sulphate Fractionation ◽  
Identification And Characterization

The extremely thermoacidophilic archaeon Sulfolobus solfataricus utilizes D-glucose as a sole carbon and energy source through the non-phosphorylated Entner–Doudoroff pathway. It has been suggested that this micro-organism metabolizes D-gluconate, the oxidized form of D-glucose, to pyruvate and D-glyceraldehyde by using two unique enzymes, D-gluconate dehydratase and 2-keto-3-deoxy-D-gluconate aldolase. In the present study, we report the purification and characterization of D-gluconate dehydratase from S. solfataricus, which catalyses the conversion of D-gluconate into 2-keto-3-deoxy-D-gluconate. D-Gluconate dehydratase was purified 400-fold from extracts of S. solfataricus by ammonium sulphate fractionation and chromatography on DEAE-Sepharose, Q-Sepharose, phenyl-Sepharose and Mono Q. The native protein showed a molecular mass of 350 kDa by gel filtration, whereas SDS/PAGE analysis provided a molecular mass of 44 kDa, indicating that D-gluconate dehydratase is an octameric protein. The enzyme showed maximal activity at temperatures between 80 and 90 °C and pH values between 6.5 and 7.5, and a half-life of 40 min at 100 °C. Bivalent metal ions such as Co2+, Mg2+, Mn2+ and Ni2+ activated, whereas EDTA inhibited the enzyme. A metal analysis of the purified protein revealed the presence of one Co2+ ion per enzyme monomer. Of the 22 aldonic acids tested, only D-gluconate served as a substrate, with Km=0.45 mM and Vmax=0.15 unit/mg of enzyme. From N-terminal sequences of the purified enzyme, it was found that the gene product of SSO3198 in the S. solfataricus genome database corresponded to D-gluconate dehydratase (gnaD). We also found that the D-gluconate dehydratase of S. solfataricus is a phosphoprotein and that its catalytic activity is regulated by a phosphorylation–dephosphorylation mechanism. This is the first report on biochemical and genetic characterization of D-gluconate dehydratase involved in the non-phosphorylated Entner–Doudoroff pathway.

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