Mechanism of activation of light-activated phosphodiesterase and evidence for homology with hormone-activated adenylate cyclase

Conference · Sat Jan 01 00:00:00 EST 1983

OSTI ID:5922659

Bitensky, M W; Yamazaki, A; Wheeler, M A; George, J S; Rasenick, M M

Light-activated cGMP phosphodiesterase (PDE) is one of the effector proteins in the rod outer segments in vertebrate retina. The hydrolysis of cGMP in rod occurs with a speed and light sensitivity which suggests a role for this hydrolysis in visual transduction. In fact, there is electrophysiological data which supports the possibility that cGMP could regulate rod membrane voltage. PDE shows very rapid activation in the presence of photons and GTP. We have called attention to the intriguing analogy between light activated rod phosphodiesterase and hormone activated adenylate cyclase. A number of studies have implicated the binding of GTP to a GTP binding protein as a factor in the hormone dependent activation of adenylate cyclase. Moreover, Cassel and Selinger have shown that hydrolysis of GTP is a component in the inactivation of the hormone dependent adenylate cyclase. We review here recent additional data which provide specific molecular details of the mechanism of light activation of rod PDE as well as demonstrate the exchange of components between light activated PDE and hormone activated cyclase.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5922659
• Report Number(s): LA-UR-83-1855; CONF-830678-1; ON: DE83014141
• Resource Relation: Conference: 5. international conference on cyclic nucleotides and protein phosphorylation, Milan, Italy, 27 Jun 1983; Other Information: Portions are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOSPHODIESTERASES
CHEMICAL ACTIVATION
BIOCHEMISTRY
CYCLASES
HORMONES
HYDROLYSIS
PHOTOCHEMICAL REACTIONS
RETINA
BODY
BODY AREAS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ENZYMES
ESTERASES
EYES
FACE
HEAD
HYDROLASES
LYASES
LYSIS
ORGANS
SENSE ORGANS
SOLVOLYSIS
550200* - Biochemistry