Studies on Esterase of Pieris rapae L. II. Biochemical Properties and Immunological Studies

배추흰나비(Pieris rapae L.)의 esterase에 관한 연구 II. 생화학적 특성 및 면역학적 연구

The properties of three esterases (E2, E6 and E11) which were previously purified from Pieris rapae L. were determined and physiological role of E6 was inferred using immunological methods. Based on inhibitor study, all of the purified esterases were found to be carboxylesterases (EC 3.1.1.1). The Km values for E2, E6 and E11 were determined to be 6.89 X 10-$^4$M. 3.19 $\times$ l0-$^4$M and 3.69 X 10-$^4$M, respectively. The molecular weights of E2, E6 and E11 were estimated to be 42 KD, 81 KD and 174 KD, respectively. The isoelectric points of E2, E6 and E11 were estimated to be pH 5.54, pH 5.89 and pH 6.50, respectively. The concentration of E6 during development was highest at the late 5th instar larval stage and that according to organs at the same stage was highest in midgut. These results suggest that E6 might be a hydrolase involved in the digestion of dietary lipids.

배추흰나비로부터 정제된 3개의 esterase의 특성을 조사하였으며 면역학적 연구를 통해 E6의 생리적 역할을 추정하였다. 억제제의 연구결과, E2, E6, E11 모두 carboxylesterase임이 밝혀졌다. Km 값은 E2, E6 및 E11이 각각 6.89 X 10-$^4$M. 3.19 $\times$ l0-$^4$M, 3.69 X 10-$^4$M이었다. 분자량은 E2, E6 및 E11이 각각 42 KD, 81 KD, 174 KD이었고 등전점은 각각 pH 5.54, pH 5.89, pH 6.50이었다. 변태에 따른 E6의 농도는 5령 말기에서 가장 높았으며 특히 중장조직에서 높게 나타났다. 따라서 E6은 소화효소로 사료된다.