Purification and Characterization of a Novel Redox-Regulated Isoform of Myrosinase (尾-Thioglucoside Glucohydrolase) from Lepidium latifolium L.
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- 作者：Rohini Bhat ; Tarandeep Kaur ; Manu Khajuria ; Ruchika Vyas ; Dhiraj Vyas
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2015
- 出版时间：December 2, 2015
- 年：2015
- 卷：63
- 期：47
- 页码：10218-10226
- 全文大小：496K
- ISSN：1520-5118
文摘
Myrosinase (ExPASy entry EC 3.2.1.147) is involved in the hydrolysis of glucosinolates to isothiocyanates, nitriles, and thiocyanates that are responsible for various ecological and health benefits. Myrosinase was purified from the leaves of Lepidium latifolium, a high-altitude plant, to homogeneity in a three-step purification process. Purified enzyme exists as dimer in native form (鈭?60 kDa) with a subunit size of 鈭?0 kDa. The enzyme exhibited maximum activity at pH 6.0 and 50 掳C. With sinigrin as substrate, the enzyme showed K<sub>msub> and V<sub>maxsub> values of 171 卤 23 渭M and 0.302 渭mol min<sup>鈥?sup> mg<sup>鈥?sup>, respectively. The enzyme was found to be redox-regulated, with an increase in V<sub>maxsub> and K<sub>catsub> in the presence of GSH. Reduced forms of the enzyme were found to be more active. This thiol-regulated kinetic behavior of myrosinase signifies enzyme鈥檚 strategy to fine-tune its activity in different redox environments, thus regulating its biological effects.