洋紫荊(Bauhinia purpurea)種子中胰蛋白酶抑制劑之純化及其特性

Purification and Characterization of a Trypsin Inhibitor from Bauhinia purpurea Seeds

洪志宏(Chih-Hung Hung) ； 董陳峰(Chen-Feng Dong) ； 陳韻帆(Yun-Fan Chen) ； 周孝怡(Hsiao-Yi Chou) ； 黃靖晏(Chin-Yen Huang) ； 王海龍(Hai-Lung Wang)

《元培學報》 17期 (2010/12) Pp. 17-28

https://doi.org/10.30171/JYUST.201012.0002

摘要

利用硫酸銨分割，Sephadex G-50凝膠過濾色層分析法，DE-52 cellulose陰離子交換樹脂及trypsin-Sepharose 4B親和性管柱，可以從洋紫荊(Bauhinia purpurea)種子中純化出一種胰蛋白酶抑制劑(Bauhinia purpurea trypsin inhibitor)，簡稱BPTI。洋紫荊屬於豆目(Leguminosae)、蘇木科(Caesalpiniaceae)，學名：Bauhinia purpurea Linn.，利用SDS-PAGE分析所純化之BPTI，得知其分子量約20 kDa，由單一條多胜鏈所組成，是屬於Kunitz-type蛋白酶抑制劑。進一步對此蛋白的性質研究，發現BPTI在60℃ 30分鐘仍保有大於50%的活性，但如果到80及100℃，則活性僅殘留27及17%左右。在廣泛的pH範圍及還原劑DTT處理，BPTI其抑制胰蛋白酶的活性仍然非常穩定，故BPTI結構的穩定與雙硫鍵的存在沒有明顯的相關性。

關鍵字

洋紫荊 ； 胰蛋白酶抑制劑 ； Kunitz-type蛋白酶抑制劑

並列摘要

A trypsin inhibitor (BPTI) was purified from seeds of Bauhinia purpurea by 70-90% ammonium sulfate precipitation, Sephadex G-50 column, DE-52 ion-exchange column and trypsin-Sepharose 4B affinity chromatography. A molecular weight of 20 kDa and single polypeptide chain was estimated by SDS-PAGE. The BPTI was found to be a thermostable Kunitztype TI that inhibits trypsin at molar ratio 1:1. The stability of BPTI was studied by exposing it to altered conditions of temperature, and measuring the residual inhibitor activity. The inhibitory activity retained at least 50% activity after being heated to 60℃ for 30 mm, but there were 73 and 83% losses of activity at 80 and 100℃ respectively. The inhibitory activity was stable over a wide p1-1 range and in the presence of DTT. The stability of RPTI is apparently not related to the presence of disulfide bridge.

並列關鍵字

Kunitz-type trypsin inhibitor ； Bauhinia purpurea ； BPTI