Study On Purification And Enzymatic Properties Of Alliinase From Garlic Plant

The extremely unstable allicin and other sulfer-containing compounds is suggest as functional active compounds in garlic plant, which is liberated from the more stable alliin by the alliinase if fresh garlic plant is crunched. The garlic plant is raw materials, the alliinase in garlic plants were extracted by Na+/K+phosphate buffer, and purified by Polyethylene Glycol8000precipitation, ultrafiltration, Sephadex G-75column. SDS-PAGE was use for verify its purity. The enzymatic properties of alliinase from garlic plant were studied by raw alliin as substrate.antioxidant capability and antibacterial activities of enzyme treatment products of alliin were studied. The results show:The alliinase in garlic plant was extracted using Na+/K+phosphate buffer (pH7.0), add PEG8000into alliinase solution to the concentration of15%(m/v) in order to precipitate a part of impurity protein, centrifuge, the PEG8000was add to the supernatant to the concentration of25%(m/v), collect the precipitation. Purified by ultrafiltration membrane (30K) under0.1MPa for two times, and Sephadex G-75column was used separate alliinase from protein. SDS-PAGE showed that the unpurposed propein was decreased.The enzymatic properties of alliinase:The optimum reactive temperature was50℃and the optimum pH was6.5, Under the optimum conditions, the values of Km and Vmax were2.38mmol·L-1and0.05μmol·min-1. The activity of alliinase was steady relatively at30℃, near neutral pH (pH6-9) was more favorable to keep the activity of alliinase. Mg2+, EDTA-Na, Fe3+, glycerin, PLP and glucose activate the activity of the alliinase, while Ba2+, Ca2+, Co2+, Cu2+and L-cystein inhibit the enzyme activity. The carbohydrate content of alliinase was7.65%and the glycopeptide linkage was inferred to be N-type.The DPPH scavenging activities, the OH-scavenging activities and the total antioxidant ability was significantly enhanced by different of enzyme treatment products of alliin. The DPPH·scavenging activities and OH·scavenging activities varied inversely with enzyme treatment time.The influence on the total antioxidant ability was not obvious.Enzyme treatment products of alliin had all inhibitory action to Escherichia coli, Salmonella, Staphylococcus aureus and proteusbacillus vulgaris. The inhibitory effects to Escherichia coli and Salmonella were prominent while they had less activity against proteusbacillus vulgaris, and The inhibitory effects to Staphylococcus aureus was weakest.