ISSN:
1432-1017
Keywords:
Cyclic GMP
;
Phosphodiesterase
;
Rhodopsin
;
Iodopsin
;
Retinal analogues
;
Rod outer segment
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract Activation of guanosine 3′,5′-cyclic monophosphate (cGMP) phosphodiesterase (EC 3.1.4.35.) in frog rod outer segment membrane by rhodopsin and its analogues was investigated. The Schiff-base linkage between opsin and retinal in rhodopsin was not always necessary for the phosphodiesterase activation. The binding of Β-ionone ring of retinal to a hydrophobic region of opsin was not enough to induce the enzyme activation. A striking photo-activation of the enzyme was induced by photo-isomerization of rhodopsin analogues from cis to trans form. It seems probable that an “expanded” conformation of opsin around the retinylidene chromophore induced by the cis to trans isomerization may be the trigger for the activation of phosphodiesterase. On the other hand, the phosphodiesterase in frog rod outer segment was activated by warming of bathorhodopsin to −12
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00535660
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