Novel bacterial myrosinases to be used in the preparation of isothiocyanates.
學生姓名:
許芷菱
指導教授:
林泓廷
學期:
111下
摘 要:
Myrosinase can hydrolyze glucosinolates to generate isothiocyanates, which have a variety of excellent biological activities. To further improve the efficiency of isothiocyanates preparation, it is necessary to explore novel sources of myrosinases. It is reported that Shewanella baltica Myr-37, isolated from marine mud, was capable of producing a novel myrosinase (Smyr37), with a molecular weight of 100 kDa. Another study indicated that a novel myrosinase Rmyr (69 kDa) originally from Rahnella inusitata was heterologously expressed in Escherichia coli. Smyr37 showed the highest activity at 50°C and pH 8.0. The sinigrin- and glucoraphanin-hydrolyzing activities of Smyr37 were determined to be 6.95 and 5.87 U/mg, respectively. Additionally, the purified Rmyr showed the highest activity at 40°C and pH 7.0, and has a half-life of 12 days at 30°C. The sinigrin-, glucoraphenin-, and glucoraphanin-hydrolyzing activities of Rmyr were 12.73, 4.81, and 6.99 U/mg, respectively. Moreover, the crude enzyme of Smyr37 could efficiently degrade glucoraphanin into sulforaphane within 25 min and its corresponding conversion efficiency was 89%. And Rmyr could efficiently degrade the radish seed-derived glucoraphenin and the broccoli seed-derived glucoraphanin into sulforaphene and sulforaphane within 10 min. The highest conversion efficiencies of sulforaphane from glucoraphanin and sulforaphene from glucoraphenin reached up to 92.48 and 97.84%, respectively. Therefore, Smyr-37 and Rmyr are novel biocatalysts for efficient and large-scale preparation the products of glucosinolates
1112專題討論摘要_許芷菱.pdf