Enzymatic Properties of Pectin Esterase from Aspergillus sp.

Aspergillus속(屬)이 생성(生成)하는 Pectin Esterase의 효소학적(酵素學的) 성질(性質)

The enzymatic properties of pectin esterase from Aspergillus sp. were studied. The optimum conditions for the enzyme reaction were pH 4.2 and temperature of $45^{\circ}C$. The crude enzyme was very stable at pH range of $2.2{\sim}4.6$, but about 20 percent of activity was lost at the range of pH $5.4{\sim}8.0$. The crude enzyme was very stable at $50^{\circ}C$ for one hour, however almost 100 percent of enzyme activity was lost at $70^{\circ}C$ for 30 minutes. The pectin esterase activity of crude enzyme was greatly inhibited by addition of sodium chloride at lower pH range. That is, the inhibition rates of enzyme activity at pH 3.0 and 4.0 were 47% and 28% in concentration of 1M sodium chloride, respectively. The enzyme activity was not affected by sodium chloride at pH 7.0 at different concentration of sodium chloride. Although the enzyme activity was not affected by addition of sucrose, it was slightly inhibited at higher concentration of sucrose.

내산성(耐酸性) pectinase를 강하게 생성(生成)하는 Aspergillus속(屬)의 한 균주(菌株)에 대한 P.E.의 효소학적(酵素學的) 성질(性質)을 검토(檢討)하였다. 본효소(本酵素)의 최적반응(最適反應) pH는 4.2부근이며 최적반응온도最適反應溫度는 $45^{\circ}C$ 부근이고 PH $2.2{\sim}4.6$에서 안정(安定)하며 pH $5.4{\sim}8.0$에서도 비교적(比較的) 안정(安定)하여 20%정도의 효소실활(酵素失活)에 지나지 않았으므로 pH에 대해 비교적 안정(安定)한 것으로 나타났다. 열(熱)에 대한 안정성(安定性)은 $50^{\circ}C$에서 1시간 처리(處理)로 극히 안정(安定)하며 $70^{\circ}C$에서 30분(分)처리로 완전히 실활(失活)했다. 본효소(本酵素) 작용(作用)에 있어서 NaCl은 조해작용(阻害作用)을 나타냈으며 pH가 낮아질수록 조해(阻害)가 뚜렷해서 pH 7.0에서는 거의 영향이 없으나 1.0M NaCl농도일 때 pH 3.0에서는 47%, pH 4.0에서는 28%의 상대활성조해(相對活性阻害)를 나타내었다. sucrose에 대한 영향을 본 결과 본효소(本酵素)에 대하여 거의 영향이 없으나 고농도(高濃度)에서는 약간의 조해(阻害)를 보였다.