本研究乃探討綠豆於發芽過程中脂氧合酶之變化及其特性。將綠豆浸水4～5小時後，於自動培育機中發芽4天，於發芽第1.5天之脂氧合活性達到最高，約為原來酵素活性之5倍。將發芽1.5天之綠豆芽製備為粗抽出液再經20-50％硫銨分劃、Hydroxyapatite管柱層析及Superdex pg 200膠過濾分離後，脂氧合活性(LOX)純化了18倍，回收率為 4.3％。該部分純化的LOX之最適溫度及pH分別為40℃及pH 6.4，於溫度40℃以下及pH5.5～7.5下綠豆芽LOX之活性穩定。該LOX對於不同脂肪酸之反應性以18：2最高，其次為20：5、18：3、20：4、22：6。利用正相高效液相層析分析得知，綠豆芽LOX對18：2之氧化產物為9-及13-HODE，比率為6.3：1；對18：3為13-HOTE (100%)。綠豆芽酵素抽出液與不同過氧化物反應後，可形成濃厚之green, cucumber, melon等風味。 Lipoxygenase (LOX) (linoleate:oxygen oxidoreductase, E.C. 1.13.11.12) activity of mung bean during germinating process was studied. The mung bean seedlings were cultivated over a period of 4 days and LOX activity increased and reached a maximum about 5-folds at dat 1.5. LOX from mung bean seedlings was further isolated and purified using 20-50% saturation of ammonium sulfate fractionation, hydroxyapatite column chromatography and gelfiltration on Superdex pg 200. The optimal pH of the partially purified LOX was 6.4, and optimal temperature was 40 oC. At pH ranged 5.5 to 7.5 and temperature below 40 oC, the LOX activity was stable. The LOX from mung bean seedlings showed the highest reactivity toward 18:2 followed by 20:5, 18:3, 20:4 and 22:6. Based on retention time in normal phase HPLC, the products of 18:2 reacting with LOX of mung bean seedlings were 9- and 13-HpODE (hydroperoxyoctadecadienoic acid) at a ratio of 6.3:1, that from 18:3 was 13-HpOTE (hydroperoxyoctadecatrienoic acid). Mung bean extract treated with 13-HpODE or 13-HpOTE developed strong green odor, while those treated with 9-HpODE or 9-HpOTE produced sweet, cucumber or melon-like aroma.
