Purification and characterization of an enzyme from a strain ofOchrobactrum anthropithat degrades condensation products of urea and formaldehyde (ureaform)

1997 ◽  
Vol 43 (12) ◽  
pp. 1111-1117 ◽  
Author(s):  
Thomas Jahns ◽  
Roswitha Schepp ◽  
Heinrich Kaltwasser

An enzyme hydrolyzing the condensation products of urea and formaldehyde (ureaform) was purified and characterized from a bacterium isolated from soil and described as Ochrobactrum anthropi UF4. The enzyme designated as methylenediurea amidinohydrolase (methylenediurea deiminase) hydrolyzed ureaform condensation products of different length (methylenediurea, dimethylenetriurea, trimethylenetetraurea) to ammonium, formaldehyde, and urea at molar ratios of 2:1:1 (methylenediurea), 4:2:1 (dimethylenetriurea), and 6:3:1 (trimethylenetetraurea). Two other substrates, ureidoglycolate and allantoate, were also hydrolyzed, yielding glyoxylate and urea (ureidoglycolate) and glyoxylate, urea, and ammonium (allantoate), respectively. The molecular mass of the enzyme was determined by size exclusion chromatography to be 140 ± 25 kDa; the enzyme was composed of identical subunits of 38 ± 5 kDa, indicating that the native enzyme has a tetrameric structure. Growth of the bacterium in the presence of ureaform specifically induced the methylenediurea deiminase and no complete repression of enzyme synthesis by ammonium was observed.Key words: ureaformaldehyde, methylenediurea deiminase, fertilizer, Ochrobactrum anthropi.

1995 ◽  
Vol 311 (1) ◽  
pp. 307-315 ◽  
Author(s):  
P Schneider ◽  
A Nikolaev ◽  
M A Ferguson

GDP-D-arabinopyranose (GDP-D-Ara) is the precursor of the uncommon D-arabinopyranose residues present in the glycoconjugates of a few trypanosomatid parasites. Biosynthetic labelling experiments with Crithidia fasciculata showed that GDP-D-Ara could be labelled with [3H]D-Ara, [2-3H]D-Glc and [6-3H]D-Glc, but not with [1-3H]D-Glc, suggesting that D-Ara can be either taken up directly by the parasite or derived from D-Glc through a pathway involving the loss of carbon C-1. In vivo pulse-chase experiments indicated that D-Ara was sequentially incorporated into D-Ara-1-PO4 and GDP-D-Ara prior to transfer to the acceptor glycoconjugate, lipoarabinogalactan. An MgATP-dependent D-arabino-1-kinase activity present in soluble extracts of C. fasciculata was purified away from phosphatase activities by size-exclusion chromatography. The D-arabino-1-kinase had an apparent molecular mass of 600 kDa, a neutral optimum pH, and displayed substrate inhibition at D-Ara concentrations above 100 microM. It had a KmATP of 1.7 mM and a KmAra of 24 microM. Competition studies indicated that the orientation of every single hydroxyl residue was important for D-Ara recognition by the enzyme, but that methyl or hydroxymethyl groups could be tolerated as equatorial substituents on C-5 of D-Ara. The partially purified D-arabino-1-kinase activity was used in the chemico-enzymic synthesis of GDP-[5-3H]D-Ara from [6-3H]D-GlcN.


Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2272
Author(s):  
Hussein Kaddour ◽  
Malik Tranquille ◽  
Chioma M. Okeoma

Extracellular vesicles (EVs) are cell-derived membranous particles secreted by all cell types (including virus infected and uninfected cells) into the extracellular milieu. EVs carry, protect, and transport a wide array of bioactive cargoes to recipient/target cells. EVs regulate physiological and pathophysiological processes in recipient cells and are important in therapeutics/drug delivery. Despite these great attributes of EVs, an efficient protocol for EV separation from biofluids is lacking. Numerous techniques have been adapted for the separation of EVs with size exclusion chromatography (SEC)-based methods being the most promising. Here, we review the SEC protocols used for EV separation, and discuss opportunities for significant improvements, such as the development of novel particle purification liquid chromatography (PPLC) system capable of tandem purification and characterization of biological and synthetic particles with near-single vesicle resolution. Finally, we identify future perspectives and current issues to make PPLC a tool capable of providing a unified, automated, adaptable, yet simple and affordable particle separation resource.


Author(s):  
Lia Siti Nur'amaliyah ◽  
Dewi Seswita Zilda ◽  
Nisa Rachmania Mubarik

Streptomyces sp. TTA 02 SDS 14 is a transglutaminase producing bacteria which previously had been  screened along with more than one hundred isolates. This research aimed to purify and characterize transglutaminase from this strain. Transglutaminase was purified from crude enzyme by ultrafiltration, Q-Sepharose ion exchange chromatography and Sepacryl S200 size exclusion chromatography sequentially, obtaining yield and purification fold of  1.36%  and 27 folds, respectively. The molecular weight of the purified transglutaminase was 72 kDa detected by zymogram gel electrophoresis. The optimum temperature and pH were 50°C and 6. The transglutaminase was stable at 45°C and could be activated in the presence of 5 mM and 10 mM of Na+, K+, Li+,Ca2+, Mg2+, BPB (4-bromo-phenacyl bromide), and IAA (iodo acetamide acid), but the activity was inhibited by  the presence of Cu+, Zn2+, and PMSF (phenyl methyl sulfonyl fluoride).


e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Hayet Bendaikha ◽  
Gérald Clisson ◽  
Abdelouahad Khoukh ◽  
Jeanne François ◽  
Seghier Ould Kada

AbstractMethacrylate-terminated Poly(1,3 dioxolane) (PDXL) macromonomers were synthesized by cationic ring-opening polymerization in the presence of 2- hydroxypropyl methacrylate (2-HPMA) as transfer agent. Molecular weights, polydispersity index and functionality of the PDXL macromonomers were evaluated by size exclusion chromatography (SEC) and 1H nuclear magnetic resonance spectroscopy (1H-NMR). Copolymerizations of PDXL macromonomers, of different molecular weights, with styrene (St) and methyl methacrylate (MMA) were carried out using various feed molar ratios. The resulting polymers confirmed the grafting of PDXL with PS and PMMA by SEC and 1H-NMR Monomer reactivity ratios between the macromonomers and the comonomers were estimated from the copolymerization results. Macromonomer reactivity depends on the comonomer considered. Glass transition temperatures of the copolymers were found to decrease with an increase in the amount of PDXL in the copolymers. The values of Tg depend on the composition and the size of the PDXL grafts.


2009 ◽  
Vol 44 (4) ◽  
pp. 906-923 ◽  
Author(s):  
Anayla S. Sousa ◽  
Artemízia P. Guimarães ◽  
Caroline V. Gonçalves ◽  
Ivanildo J. Silva ◽  
Celio L. Cavalcante ◽  
...  

1990 ◽  
Vol 272 (3) ◽  
pp. 721-726 ◽  
Author(s):  
V L Koshte ◽  
W van Dijk ◽  
M E van der Stelt ◽  
R C Aalberse

A lectin (BanLec-I) from banana (Musa paradisiac) with a binding specificity for oligomannosidic glycans of size classes higher than (Man)6GlcNAc was isolated and purified by affinity chromatography on a Sephadex G-75 column. It did not agglutinate untreated human or sheep erythrocytes, but it did agglutinate rabbit erythrocytes. BanLec-I stimulated T-cell proliferation. On size-exclusion chromatography, BanLec-I has a molecular mass of approx. 27 kDa, and on SDS/PAGE the molecular mass is approx. 13 kDa. The isoelectric point is 7.2-7.5. BanLec-I was found to be very effective as a probe in detecting glycoproteins, e.g. on nitrocellulose blots.


2021 ◽  
Vol 224 (2) ◽  
pp. S92-S93
Author(s):  
Kendra Sylvester ◽  
Callie Reeder ◽  
Matthew W. Becker ◽  
Fatima Zahra Aly ◽  
Clive Wasserfall ◽  
...  

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