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International Journal of Current Microbiology and Applied Sciences (IJCMAS)
IJCMAS is now DOI (CrossRef) registered Research Journal. The DOIs are assigned to all published IJCMAS Articles.
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National Academy of Agricultural Sciences (NAAS)
NAAS Score: *5.38 (2017)
[Effective from January 1, 2017]
For more details click here

ICV 2016: 92.3
Index Copernicus ICI Journals Master List 2016 - IJCMAS--ICV 2016: 92.3
For more details click here
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706
Issues : 12 per year
Publisher : Excellent Publishers
Email : editorijcmas@gmail.com / submit@ijcmas.com
Editor-in-chief: Dr.M.Prakash
Index Copernicus ICV 2016: 92.30
NAAS RATING 2018: 5.38

Int.J.Curr.Microbiol.App.Sci.2016.5(2): 567-578
DOI: http://dx.doi.org/10.20546/ijcmas.2016.502.064


Activity of Purified Bacterial Myrosinase and its Essential Residues
Hamed M. El-Shora*, Ahmed M. El-Shobaky and Maissa M. El-Atrozy
Botany Department, Faculty of Science, Mansoura University, Egypt
*Corresponding author
Abstract:

Myrosinase (thioglucoside glucohydrolase or thioglucosidase) (EC 3.2.3.147) hydrolyzes the glucosinolate to thiocyanates, isothiocyanates, epithionitrile, nitriles, oxazolidine-thione. Myrosinase   was isolated from Bacillus thuringiensis. The enzyme was partially purified by ammonium sulfate and Sephadex G-200. The specific activity was 64 units mg-1 protein.  The optimal pH and temperature of the enzyme were 8.0 and 50 °C, respectively. The optimal incubation time was 40 min. The chelating agent α-α-dipyridyl inhibited the enzyme activity in concentration-dependent manner. Adding Triton X─100 at various concentrations resulted in an increase of the enzyme activity. Diethylpyrocarbonate (DEPC), N-ethylmaleimide (NEM), N-bromosuccinimide (NBS) and phenylglyoxal (PGO) inhibited the enzyme activity at the various tested concentrations and the inhibition was dependent on the concentration of each tested compound. Mercaptoethanol activated the enzyme activity at the tested concentrations 20, 40 and 60 mM then the activity declined with increasing the concentration. GA3 as phytohormone activated myrosinase continuously up to 80 μmol then declined at 100 µmol. The thiol compounds L-methionine, N-acetylcysteine, cysteine, thiourea and dithiothreitol (DTT) activated the enzyme and N-acetylcysteine was the best activator.


Keywords:  Bacillus thuringiensis, Myrosinase, Characterization, Essential residues, GA3
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How to cite this article:

Hamed M. El-Shora, Ahmed M. El-Shobaky and Maissa M. El-Atrozy. 2016. Activity of Purified Bacterial Myrosinase and its Essential Residues.Int.J.Curr.Microbiol.App.Sci. 5(2): 567-578. doi: http://dx.doi.org/10.20546/ijcmas.2016.502.064