钙离子对人十二指肠腺苷酸环化酶活性的抑制作用及乙二醇双四乙酸（EGTA）的影响。

The inhibition of human duodenal adenylate cyclase activity by Ca2+ and the effects of EGTA.

作者信息

Smith J A, Griffin M, Mireylees S E, Long R G

机构信息

Medical Research Centre, City Hospital, Nottingham, UK.

出版信息

FEBS Lett. 1993 Jul 26;327(2):137-40. doi: 10.1016/0014-5793(93)80157-p.

DOI:10.1016/0014-5793(93)80157-p

PMID:8335102

Abstract

This study demonstrates that the inhibition of adenylate cyclase activity by Ca2+ is enhanced in the presence of increasing [EGTA] (0, 0.3, 1, 2.5 mM) by 2 orders of magnitude. It has been established that this effect is not because of poor Ca2+ buffering by low [EGTA] or high Ca2+ binding by the membrane preparation. It is present irrespective of stimulus. We suggest the enhanced sensitivity of adenylate cyclase to Ca2+ induced by EGTA is caused by the Ca-EGTA complex being a more inhibitory species than Ca2+. Thus consideration of the effects of the Ca-EGTA complex should be made when interpreting the results from experiments involving Ca2+ and EGTA.

摘要

本研究表明，在[乙二醇双（2-氨基乙基醚）四乙酸]（EGTA）浓度增加（0、0.3、1、2.5 mM）时，Ca2+对腺苷酸环化酶活性的抑制作用增强了2个数量级。已经确定，这种效应并非由于低浓度[EGTA]对Ca2+的缓冲能力差或膜制剂对Ca2+的高结合能力所致。无论刺激如何，这种效应都存在。我们认为，EGTA诱导的腺苷酸环化酶对Ca2+敏感性增强是由于Ca-EGTA复合物比Ca2+更具抑制性。因此，在解释涉及Ca2+和EGTA的实验结果时，应考虑Ca-EGTA复合物的影响。