Purification and characterization of azurin from the methylamine-utilizing obligate methylotroph Methylobacillus flagellatus KT

2012 ◽  
Vol 58 (4) ◽  
pp. 516-522 ◽  
Author(s):  
Tatiana Y. Dinarieva ◽  
Stanislav A. Trashin ◽  
Jörg Kahnt ◽  
Arkady A. Karyakin ◽  
Alexander I. Netrusov

Methylamine dehydrogenase (MADH) and azurin were purified from the periplasmic fraction of the methylamine-grown obligate methylotroph Methylobacillus flagellatus KT. The molecular mass of the purified azurin was 16.3 kDa, as measured by SDS–PAGE, or 13 920 Da as determined by MALDI–TOF mass spectrometry. Azurin of M. flagellatus KT contained 1 copper atom per molecule and had an absorption maximum at 620 nm in the oxidized state. The redox potential of azurin measured at pH 7.0 by square-wave voltammetry was +275 mV versus normal hydrogen electrode. MADH reduced azurin in the presence of methylamine, indicating that this cupredoxin is likely to be the physiological electron acceptor for MADH in the electron transport chain of the methylotroph. A scheme of electron transport functioning in M. flagellatus KТ during methylamine oxidation is proposed.


2006 ◽  
Vol 52 (7) ◽  
pp. 651-657 ◽  
Author(s):  
Luis Morales de la Vega ◽  
J Eleazar Barboza-Corona ◽  
Maria G Aguilar-Uscanga ◽  
Mario Ramírez-Lepe

A chitinolytic enzyme from Bacillus thuringiensis subsp. aizawai has been purified and its molecular mass was estimated ca. 66 kDa by sodium dodecyl sulfate – polyacryamide gel electrophoresis (SDS–PAGE). The enzyme was able to hydrolyze chitin to chitobiosides but not carboxymethylcellulose, cellulose, pullulan, and laminarin. Optimal pH and temperature were detected at 6 and 50 °C, respectively. Stability, in the absence of substrate, was observed at temperatures less than 60 °C and pH between 5 and 8. Enzyme activity was significantly inhibited by K+ and EDTA and completely inhibited by Hg2+. Purified chitinase showed lytic activity against cell walls from six phytopathogenic fungi and inhibited the mycelial growth of both Fusarium sp. and Sclerotium rolfsii. The biocontrol efficacy of the enzyme was tested in the protection of bean seeds infested with six phytopathogenic fungi.Key words: chitinase, Bacillus thuringiensis, purification, phytopathogenic fungi.



1997 ◽  
Vol 52 (11-12) ◽  
pp. 740-746 ◽  
Author(s):  
Röbbe Wünschiers ◽  
Thomas Zinn ◽  
Dietmar Linder ◽  
Rüdiger Schulz

Abstract Purification of a soluble cytochrome c6 from the unicellular green alga Scenedesmus obliquus by a simple and rapid method is described. The purification procedure includes ammonium sulfate precipitation and non-denaturating PAGE. The N-terminal sequence of the first 20 amino acids was determined and shows 85% similarity and 75% identity to the sequence of cytochrome c6 from the green alga Monoraphidium braunii. The ferrocyto-chrome shows typical UV/VIS absorption peaks at 552.9, 521.9 and 415.7 nm. The apparent molecular mass was estimated to be 12 kD a by SDS-PAGE. EPR-spectroscopy at 20K shows resonances indicative for two distinct low-spin heme forms.



1990 ◽  
Vol 267 (2) ◽  
pp. 509-515 ◽  
Author(s):  
N M Hooper ◽  
J Hryszko ◽  
A J Turner

Aminopeptidase P (EC 3.4.11.9) was solubilized from pig kidney membranes with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) and then purified by a combination of anion-exchange and hydrophobic-interaction chromatographies. Contaminating peptidase activities were removed by selective affinity chromatography. The purified enzyme was apparently homogeneous on SDS/PAGE with an Mr of 91,000. Enzymic deglycosylation revealed that aminopeptidase P is a glycoprotein, with up to 25% by weight of the protein being due to the presence of N-linked sugars. The phospholipase-solubilized aminopeptidase P was recognized by an antiserum to the cross-reacting determinant (CRD) characteristic of the glycosyl-phosphatidylinositol anchor. This recognition was abolished by mild acid treatment or deamination with HNO2, indicating that the CRD was due exclusively to the inositol 1,2-cyclic phosphate ring epitope generated by the action of PI-PLC. The activity of aminopeptidase P was inhibited by chelating agents and was stimulated by Mn2+ or Co2+ ions, confirming the metallo-enzyme nature of this peptidase. Selective inhibitors of other aminopeptidases (actinonin, amastatin, bestatin and puromycin) had little or no inhibitory effect.



1995 ◽  
Vol 308 (3) ◽  
pp. 983-989 ◽  
Author(s):  
I N Fleming ◽  
S J Yeaman

N-Ethylmaleimide-insensitive phosphatidic acid phosphohydrolase (PAP; EC 3.1.3.4) was purified 5900-fold from rat liver. The enzyme was solubilized from membranes with octylglucoside, fractionated with (NH4)2SO4, and purified in the presence of Triton X-100 by chromatography on Sephacryl S300, hydroxyapatite, heparin-Sepharose and Affi-Gel Blue. Silver-stained SDS/PAGE indicated that the enzyme was an 83 kDa polypeptide. Sephacryl S-300 gel filtration also produced a second peak of enzyme activity, which was eluted from all of the chromatography columns at a different position from the purified enzyme. SDS/PAGE indicated that it contained three polypeptides (83 kDa, 54 kDa and 34 kDa), and gel filtration suggested that it was not an aggregate of the purified enzyme. Both forms were sensitive to inhibition by amphiphilic amines, Mn2+ and Zn2+, but not by N-ethylmaleimide. Purified PAP required detergent for activity, but was not activated by Mg2+, fatty acids or phospholipids. The enzyme was able to dephosphorylate lysophosphatidic acid or phosphatidic acid, and was inhibited by diacylglycerol and monoacylglycerol. No evidence was obtained for regulation of PAP by reversible phosphorylation.



2012 ◽  
Vol 550-553 ◽  
pp. 1747-1754
Author(s):  
Ya Li Peng ◽  
Fei Hu

Limit dextrinase is one of three main amylases in malted barley, which plays a significant role during the mashing stage of brewing. Due to very low content and similar properties compared to other amylases in malted barley, limit dextrinase is hard to separate effectively. Our work had been directed towards the extraction and purification of limit dextrinase from malted barley. Final products were obtained through fraction precipitation with ammonium sulfate and column chromatography, and purified limit dextrinase acquired a high purity of 31.23 times as much as that of crude extracts. The previous results were also confirmed by sodiumdodecyl sulphate poly-acrylamide gel electrophoresis (SDS-PAGE) revealing a single band of protein (~97KDa). Effect of temperature, pH value, and metal ion on hydrolysis characterization of limit dextrinase was investigated. The results indicated that the maximum activity of purified samples changed significantly compared with that of crude extracts. The activity of purified limit dextrinase could be activated by lower concentration of Mg2+、Ca2+、Mn2+ and inhibited by the action of Zn2+、Fe2+. But this influence was not so obvious for K+.



1983 ◽  
Vol 29 (10) ◽  
pp. 1361-1368 ◽  
Author(s):  
Thomas P. Poirier ◽  
Stanley C. Holt

Capnocytophaga ochracea acid (AcP; EC 3.1.3.2) and alkaline (AlP; EC 3.1.3.1) phosphatase was isolated by Ribi cell disruption and purified by sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS–PAGE.) Both phosphatases eluted from Sephadex G-150 consistent with molecular weights (migration) of 140 000 and 110 000. SDS–PAGE demonstrated a 72 000 and 55 000 subunit molecular migration for AcP and AlP, respectively. The kinetics of activity of purified AcP and AIP on p-nitrophenol phosphate and phosphoseryl residues of the phosphoproteins are presented.



2006 ◽  
Vol 49 (6) ◽  
pp. 881-888 ◽  
Author(s):  
Felipe Almeida Vieira ◽  
Maura da Cunha ◽  
Denise Espellet Klein ◽  
André de Oliveira Carvalho ◽  
Valdirene Moreira Gomes

In this study, beta-1,3-glucanase was isolated from Simira glaziovii secretion. The purification process was achieved by a combination of chromatographic methods and was analyzed by SDS-PAGE. The purified enzyme presented an estimated molecular mass of 35 kDa. The optimum pH of enzyme was 5.2



2021 ◽  
Author(s):  
Ralph Bock ◽  
Deserah D Strand ◽  
Daniel Karcher ◽  
Stephanie Ruf ◽  
Anne Schadach ◽  
...  

Understanding the regulation of photosynthetic light harvesting and electron transfer is of great importance to efforts to improve the ability of the electron transport chain to supply downstream metabolism. The central regulator of the electron transport chain is the ATP synthase, the molecular motor that harnesses the chemiosmotic potential generated from proton coupled electron transport to synthesize ATP. The ATP synthase is regulated both thermodynamically and post-translationally, with proposed phosphorylation sites on multiple subunits. In this study we focused on two N-terminal serines on the catalytic subunit beta, previously proposed to be important for dark inactivation of the complex to avoid ATP hydrolysis at night. Here we show that there is no clear role for phosphorylation in the dark inactivation of ATP synthase. Instead, mutation of one of the two phosphorylated serine residues to aspartate strongly decreased ATP synthase abundance. We propose that the loss of N-terminal phosphorylation of ATP beta may be involved in proper ATP synthase accumulation during complex assembly.



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