과요오드산-산화전분으로 Aspergillus sp. α-amylase를 변형시켜서 인공당단백질을 만들었다. pH 8.0에서 변형한 효소는 비변형효소의 87%, pH 9.7에서 변형한 효소는 80%의 활성이 남았다. 60℃에서의 열안정성은 α-cyclodextrin (α-CD) 존재 하에 변형하고 α-CD 존재 하에 분석한 효소가 가장 높았다. pH 안정성은 변형시켜서 α-CD 존재하에 분석한 효소가 가장 높아서 pH 3∼4와 9∼11에서 안정성이 매우 증가하였다. HPLC 분석 결과 변형시킨 것은 당결합으로 분자량이 커져서 유출시간이 빨라졌다. 반응산물 분석 결과 기질 특이성의 변화는 나타나지 않았다.

The propose of this study was to investigate the antioxidant activity of 80% ethanol extracts and various solvent fractions of dandelion (Taraxacmn officinale) leaves and roots, Total phenolics and phenolic acid contents were also examined. The total phenol content of leaves and roots were and respectively. Eight phenolic acids were separated by GC, among which caffeic acid (113.7 mg%)and m-coumaric acid (152.6 mg) were the dominant phenolic acids in leaves and roots, respectively. Amongst solvent functions of leaves and roots, the ethyl acetate fraction showed the strongest radical scavenging activity. A strong correlation was found between total phenol content and electron-donating ability, and ABTS radical scavenging activity showed a similar trend as electron-donating ability. Hydroxyl-radical-scavenging activity and lipid peroxidation were significantly higher in the ethyl acetate fraction than other factions. In particular, the SOD-like activity was highest (43.6%) in the ethyl acetate fraction of dandelion leaves, and was higher than that of trolox. Thus, the ethyl acetate fraction of dandelion leaves exhibited significant phenol content, antioxidant activity, and free-radical-scavenging effects.