Biochemical Characterization of a Novel Myrosinase Rmyr fromRahnella inusitatafor High-Level Preparation of Sulforaphene and Sulforaphane

Abstract

Myrosinase is a biotechnological tool for the preparation of sulforaphane and sulforaphene with a variety of excellent biological activities. In this study, a gene encoding the novel glycoside hydrolase family 3 (GH3) myrosinase Rmyr from Rahnella inusitata was heterologously expressed in Escherichia coli BL21 (DE3). The purified Rmyr shows the highest activity at 40 °C and pH 7.0; meanwhile, its half-life at 30 °C reaches 12 days, indicating its excellent stability. Its sinigrin-, glucoraphenin-, and glucoraphanin-hydrolyzing activities were 12.73, 4.81, and 6.99 U/mg, respectively. Rmyr could efficiently degrade the radish seedderived glucoraphenin and the broccoli seed-derived glucoraphanin into sulforaphene and sulforaphane within 10 min with the highest yields of 5.07 mg/g radish seeds and 9.56 mg/g broccoli seeds, respectively. The highest conversion efficiencies of sulforaphane from glucoraphanin and sulforaphene from glucoraphenin reached up to 92.48 and 97.84%, respectively. Therefore, Rmyr is a promising and potent biocatalyst for efficient and large-scale preparation of sulforaphane and sulforaphene.

Characterization of a Novel Myrosinase with High Activity from Marine Bacterium Shewanella baltica Myr-37

“…For instance, the optimal pH for TGG1, Cmyr, and ArMY2 are 5.5, 6.0, and 5.0, respectively [ 23 , 28 , 29 ]. As shown in Figure 3 c, metal ions (1 mM), including Zn 2+ , Mg 2+ , Ag + , Fe 3+ , Cu 2+ , Ba 2+ , K + , Ca 2+ , Pd 2+ , and Co 2+ , inhibited Smyr37 activity, which was consistent with the characteristics of the plant myrosinase and bacterial myrosinase Rmyr [ 14 ]. These results indicated that Smyr37 is a novel myrosinase with certain enzymatic properties different from those of the identified myrosinases.…”

“…The R . inusitata myrosinase Rmyr (69 kDa) exhibited good glucoraphanin-hydrolysis activity, and the optimum temperature and pH for the myrosinase activity were 40 °C and 7.0, respectively [ 14 ]. 6-phospho-β-glucosidase from E .…”

“…Although the non-isothiocyanate metabolites of glucosinolates also show some antibacterial activity, the potent anticancer activity of isothiocyanates has attracted increasing attention from researchers [ 12 , 13 ]. The effects of sulforaphane (4-methylsulfinylbutyl isothiocyanate), one of the most active isothiocyanates, on various tumor types have been investigated in several studies [ 14 , 15 , 16 ]. Plant tissue endogenous myrosinases are often used to prepare sulforaphane.…”

“…Myrosinases from Leclercia adecarboxylata can produce allyl-isothiocyanate from sinigrin [ 24 ]. The gene encoding Rahnella inusitata myrosinase was heterologously expressed in Escherichia coli BL21 (DE3), and the purified myrosinase showed excellent catalytic efficiency for the preparation of sulforaphane [ 14 ]. Although some studies have shown that human gut bacteria can convert glucosinolates to sulforaphane, the corresponding bacteria have not yet been isolated [ 25 ].…”

Characterization of Salmonella endolysin XFII produced by recombinant Escherichia coli and its application combined with chitosan in lysing Gram-negative bacteria

“…The suitability of long-term storage of endolysin XFII was tested in accordance with the method described by Wang et al, with minor modifications [ 52 ]. It was frozen at 4 °C for a few days and the residual bactericidal activity was determined by regularly sampling according to the standard assay, and the lysis curve of the storage date was obtained.…”