تنقیة أنزیم تحویل الأنجیوتنسینI) I ECA (من رئة الفأر من سلالة Wistar بإستخدام تقنیات الكروماتوغرافیا : دراسـة بیوكیمیائیة و أنزیمیة

Abstract

The angiotensin I - converting enzyme (ACE), or peptidyldipeptide hydrolase (EC. 3.4.15.1), is an enzyme, which plays an important role in the renine- angiotensin- aldosterone system. In other words, this enzyme transfers the angiotensin I to the angiotensin II. The latter has a high capacity and effeteness in the concentration of blood vessels and it contributes in the formation of angiotensin III. Angiotensin II stimulate also the production of aldosterone hormone. In addition, the previous enzyme has a number of other different functions. ECA I is a glycoprotein, contains one peptide chain and zinc element in its active site. This research aims to purify the angiotensin I-converting enzyme (ACE) from the lungs of Wistar rats using chromatography techniques on one hand, and to study its biochemical and enzymatic properties on the other. Starting from the lung extract : the purification was dependent on the extraction by a nonionic detergent (Nonidet P-40) and the utilization of DEAE- spherodex M in ion exchange chromatography. However, the sepharose was used in the affinity chromatography with lisinopril (MK-521) as a specific inhibitor, which was bounded to the MK-521 sepharose CL-4B. the result indicates that the specific enzyme activity and the yield was 11.97 u/mg and 214.643 u/mg respectively. On the other hand, the polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (PAGE-SDS) resulted in only a single band, which indicates for the purity of the enzyme and a few contaminants substances. The later can be excluded by the application of HPLC on gel filtration superose 12. In which there was an increase of specific enzyme activity and the yield in considerable quantity : 33.42u/mg and 596.96u/mg respectively and the appearance of one band by the polyacrylamide electrophoresis. In this investigation was also measured the effect of some inhibitors on enzyme activity. The findings indicated also that enalaprilate inhibitor has capacity four times of lisinopril whereas EDTA has a weak inhibition. In other words, EDTA is not a specific an inhibitor. The enzyme presents a molecular weight of 170000.