PURIFICATION AND PHARMACOLOGICAL STUDY OF ENDOTHELIN CONVERTING ENZYME

1. 内皮素-1（ET1）的测定是评价内皮素转换酶（ECE）活性的基础。我们采用放射免疫法结合反相高效液相色谱法开发了ET-1的精确测量方法。我们检测了ET-1和大ET-1对肾脏作用的影响，以研究大ET-1是否转化为ET-1。肾内输注ET-1可降低肾血流量（RBF）、尿量和肾小球滤过率（GFR），而输注大ET-1对肾血流量、尿量和肾小球滤过率（GFR）无显著影响，提示大ET-1不能转化为成熟的et。（1992）为了表征大鼠主动脉内皮素转换酶（ECE），我们制备了大鼠主动脉匀浆离心后得到的粗膜组分。我们观察了两个最佳pH值的粗膜组分的ECE活性；中性和酸性。酸性酶活性被胃抑素A、天冬氨酸蛋白酶抑制剂抑制，而中性酶活性被EDTA、EGTA或磷酰胺阻断。进一步的表征和纯化正在研究中。

1. It is essential for the assessment of endothelin converting enzyme (ECE) activity to measure endothelin-1(ET1). We developed the precise measurement for ET-1 using radioimmunoassay combined with reverse phase HPLC.2. We examined the effects of ET-1 and big ET-1 on the renal action to study whether or not big ET-1 is converted to ET-1. Intrarenal infusion of ET-1 decreased renal blood flow(RBF), urine output and glomerular filtration rate (GFR), whereas infusion of big ET-1 did not significantly affect RBF, GFR, and urine output, suggesting that big ET-1 could not be converted to mature ET-1.1992To characterize the endothelin converting enzyme (ECE) in rat aorta, we prepared the crude membrane fractions obtained by homogenization and centrifugation of homogenate of rat aorta. We observed the ECE activities in the crude membrane fractions which had two optimal pH ; neutral and acidic. Acidic enzyme activity was inhibited by pepstatin A, aspartic protease inhibitor, whereas neutral enzyme was blocked by EDTA, EGTA or phosphoramidon. Further characterization and purification are under investigation.