Abstract
For the production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (ascorbic acid-2-g1ucoside, AA-2G) from ascorbic acid, the usability of spinach seed as the source of ${\alpha}-glucosidase$ having transglucosylation activity was studied. The optimum conditions for the production of AA-2G from ascorbic acid and glucose donor were investigated by using crude extract of Spinachia oleracea L. Woosung, the selected source of enzyme. The production of AA-2G was the highest with 1.053 mM when spinach seeds were grown for 2 days after germination. Maltose was the most effective glucose donor, and the optimum concentration of ascorbic acid and maltose were 175 mM and 225 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 60 units. The most effective buffer was sodium acetate and its optimum concentration was 175 mM. The optimum pH and temperature were 5.0 and $65^{\circ}C$, respectively. Under the optimum condition, 2.14 mM of AA-2G was produced from ascorbic acid after 50 minutes of reaction.
Ascorbic acid로부터 $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid(ascorbic acid-2-glucoside, AA-2G)를 생산하기 위하여, transglucosylation 활성을 가지는 시금치 종자의 ${\alpha}-glucosidase$를 효소원으로 이용하였다. 시금치 종자로 사용한 Spinachia oleracea L. WooSung의 조효소액의 ${\alpha}-glucosidase$ 활성은 발아 후 3일 째에 가장 높게 나타났으며, AA-2G의 생산은 2일 키운 시금치의 조효소액을 이용하였을 때, 생산량이 1.053 mM로 가장 높았다. 조효소액을 이용한 AA-2G 생산에 있어서 glucose 공여체로는 maltose가 가장 좋았으며, maltose와 ascorbic acid의 최적 농도는 각각 225 mM과 175 mM이었다. ${\alpha}-glucosidase$는 60 unit를 사용했을 때 생산량이 가장 좋았다. 효과적인 반응완충용액은 sodium acetate 완충액이었으며, 최적 농도는 175 mM이었다. 최적 pH및 반응온도는 각각 5.0과 $65^{\circ}C$였고, 최적 반응조건 하에서 50분 반응 후에 ascorbic acid로부터 2.30 mM의 AA-2G가 생산되었다.
