鲜食玉米脂氧合酶的酶学性质

Lipoxygenase Activity of Fresh Corn

本实验研究鲜食玉米脂氧合酶(lipoxygenase,LOX)的酶学性质。以新鲜甜玉米、糯玉米籽粒及其胚为试材,采用紫外分光光度法,以亚油酸为底物,探讨了酶提取部位、酶促反应温度、pH值及底物浓度对LOX活性的影响。结果表明,鲜食玉米胚中LOX活性显著高于鲜食玉米籽粒,其最适反应温度为55℃,最适反应pH值为6.0,最适底物浓度为8.0mmol/L,提高温度和延长处理时间能有效地钝化LOX。

The factors for fresh corn lipoxygenase （LOX） were investigated by using spectrophotometric assay. Using linoleic acid as the substrate and fresh sweet corn and waxy corn as samples, LOX activity was determined in reaction system with different extraction positions, enzymatic reaction pH levels and reaction temperatures and substrate concentrations. The results indicated that LOX activity in the germ was significantly higher than that in the whole kernel, and the enzyme had optimal temperature of 55 ℃, optimal pH of 6.0, and optimal substrate concentration of 8.0 mmol/L. The thermal stability of LOX was significantly inhibited by increasing temperature and prolonging heat treatment.