A light‐stimulated increase of cyclic GMP in squid photoreceptors

FEBS Letters

Saibil, Helen R.¹ 

[1] King's College London, Biophysics Department, 26–29 Drury Lane, London WC2, England

关键词: Invertebrate photoreceptor;    GTP-binding protein;    Cyclic nucleotide;    Visual transduction;   

DOI  :  10.1016/0014-5793(84)80248-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Photoreceptor outer segments isolated from squid retina are known to contain a light-activated GTP-binding protein. Here it is shown that these photoreceptors contain around 0.01 mol cyclic GMP per mol rhodopsin. Adding GTP in the dark stimulates the production of 0.0003–0.001 mol cyclic GMP/mol rhodopsin per min. GTP and light cause a 2-fold faster increase in cyclic GMP. These results show that either (1) squid rhodopsin activates a guanylate cyclase, or (2) there is a constant guanylate cyclase activity and photoexcited rhodopsin inhibits a cyclic GMP phosphodiesterase.

【 授权许可】

Unknown