Abstract: Alliinase (EC 4.4.1.4) was isolated from stalks of chive (Allium schoenoprasum L.), and its enzymatic properties were investigated. The enzyme was purified to apparent homogeneity using various steps, including homogenizing, centrifuging, ammonium sulfate precipitating, dialyzing, DEAE-52 ion exchange chromatography and Sephadex G200 gel filtration chromatography. SDS-PAGE electrophoresis was used to analyze the purity of alliinase. The results showed that the purity of alliinase was high and reached up to electrophoresis purity. The molecular weight of the subunit was 54.5 ku. The specific activity of the pure alliinase was 11.44 U/mg, and the activity recovery rate was 32.1%, which exhibited 19.6-fold enhancement in purity. The optimal reaction temperature and pH of purified alliinase were 45 ℃ and 7.0, respectively. Kinetic studies showed that Km and Vmax of alliinase using S-methyl-L-cysteine sulfoxide as the substrate were 45.31 mmol/L and 40.32 μmol/(mg·min), respectively.

Key words: chive (Allium schoenoprasum L.), alliinase, isolation and purification, enzymatic properties