National Academy of Agricultural Sciences (NAAS)
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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 2018: 95.39 NAAS RATING 2020: 5.38 |
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.
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