과요오드산-산화전분으로 보리 $eta$-amylase(Bio-zyme ML, 일본 아마노제약)를 변형시켜서 인공당단백질을 만들었다. pH 8.0에서 변형한 효소는 비변형효소의 92%, pH 9.7에서 변형한 효소는 42%의 활성이 남았다. 6$0^{circ}C$에서의 열안정성은 $alpha$-cyclodextrin ( $alpha$-CD) 존재 시에 변형하여 $alpha$-CD존재시 분석한 효소는 10분 뒤에 비활성의 8%가 남은 반면 변형하지 않은 효소는 4.5%밖에 남지 않았다. pH안정성은 변형 시켜서 $alpha$-CD존재 하에 분석한 효소가 가장 높아서 pH 2~5와 7~12에서 안정성이 매우 증가하였다. HPLC분석 결과 효소는 두 개의 피크를 나타냈으며 변형시킨 것은 당결합으로 분자량이 커져서 유출시간이 약간 빨라졌다.
The stabilization of barley $eta$-amylase(Biozyme ML, Amano) was attained by modification with periodate-oxidized soluble starch. The specific activities of modified enzyme at pH 9.7 and pH 8.0 were 42% and 92%, respectively, compared with that of native enzyme. The pH stability of modified enzyme was increased at pH 2~5 and 7~12 in the presence of $alpha$-cyclodextrin( $alpha$ -CD) compared wish that of native enzyme. Thermal stability of the modified enzyme was increased. After treatment at 6$0^{circ}C$ for 10min. the activity remained 8% for the enzyme modified at pH 8.0 in the presence of $alpha$-CD, 4.5% for the native enzyme. The native enzyme and modified enzyme showed two peak in HPLC. The molecular weight of the modified enzyme was slightly increased in HPLC analysis.
