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

FEBS Letters

Smith, Julie A.¹  Long, Richard G.¹  Griffin, Martin²  Mireylees, Stewart E.² 

[1] Medical Research Centre, City Hospital, Nottingham, NG5 1PB, UK;Department of Life Sciences, Nottingham Trent University, Nottingham, NG11 8NS, UK

关键词: Adenylate cyclase;    Calcium;    EGTA;    Human duodenum;    GMP-PNP;    5'-guanylyl-imidodiphosphate;    Fura-2;    1(2(5-carboxyoxozol-2-yl)-6-ammobenzo-furan-5-oxy)-2-(2'-amino-5'-methylphenoxyl)-ethane-N;    N;    N';    N'-tetraacetic acid;   

DOI  :  10.1016/0014-5793(93)80157-P

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown