降钙素基因相关肽衍生物的制备及降血压功能研究

用PCR法将人的降钙素基因相关肽(calcitonin gene related—peptide，CGRP)基因克隆到表达载体pGEX-4T-2的GST基因后，构建成一个新的表达质粒pGEX—CGRP．另外分别将2个有降压功能的小肽HHL和RPLKPW的基因克隆到CGRP基因后，构建成2个表达质粒pGEX—CGRP-3AA和pGEX—CGRP-6AA．将此3个表达质粒转化到大肠杆菌TG1中，获得3个高表达的融合蛋白：GST—CGRP，GST—CGRP—HHL，GST—CGRP—RPLKPW；通过G1utathione Sepharose 4B亲和层析纯化融合蛋白，测定蛋白浓度，利用自发性高血压大鼠(spontaneously hypertensive rat，SHR)来检测蛋白的降血压功能，发现融合蛋白GST—CGRP—HHL具有显著的降压效果，能使舒张压下降8．0kPa，且降压维持时间延长，达到70min以上．

The Design of Calcitonin Gene Related-peptide Derivants and the Study of Anti-hypertensive Activity

A new expression vector,pGEX-CGRP,was constructed by PCR,in which a Calcitonin gene related-peptide (CGRP) gene was cloned into pGEX-4T-2 under GST gene. Other two expression vectors,pGEX-CGRP-3AA and pGEX-CGRP-6AA,were cloned respectively by inserting small peptides HHL and RPLKPW behind the CGRP gene. After transforming these vectors into E.coli TG1,three highly expressed fusion proteins: GST-CGRP,GST-CGRP-HHL,GST-CGRP-RPLKPW were obtained. By running through Glutathion Sepharose 4B affinity chromatography,the fusion proteins were purified. After measuring the protein concentration,each fusion protein was studied by intramuscular injection into a spontaneous hypertensive rat (SHR). The result indicated that fusion protein GST-CGRP-HHL has a significant anti-hypertensive effect. It can decrease the diastolic pressure for 8.0 kPa and extend the anti-hypertensive time for 70 minutes.