Open AccessEvidence for a Guanosine‐3′: 5′‐Monophosphate‐Binding Protein from Rat Cerebellum
Author(s) -
Sold Guido,
Hofmann Franz
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03467.x
Subject(s) - guanosine , trypsin , adenosine , chemistry , nucleotide , binding site , biochemistry , ammonium sulfate , chromatography , enzyme , gene
Guo‐3′:5′‐ P and Ado‐3′:5′‐ P (guanosine and adenosine 3′: 5′‐monophosphate) are bound by a supernatant fraction of homogenates from rat cerebellum. Treatment of the supernatant fraction with trypsin destroyed the ability of the supernatant fraction to bind either of the cyclic nucleotides. For Ado‐3′:5′‐ P a hyperbolic saturation curve was obtained and an apparent K d of 8.5 nM was estimated. At a saturating concentration of 0.1 μM between 6 and 8 pmol per mg extracted protein was bound. For Guo‐3′: 5′‐ P two different types of binding sites were observed; one nonspecific site from which Guo‐3′: 5′‐ P could be displayed by low concentrations of Ado‐ 3′:5′‐ P and one, which was specific for Guo‐3′: 5′‐ P . The apparent K d of the specific site for Guo‐3′:5′‐ P was 12 nM and at a saturating concentration of 0.1 μM 1.5 pmol per mg extracted protein were bound. The Guo‐3′:5′‐ P binding protein was partially separated from an Ado‐3′: 5′‐ P ‐dependent protein kinase by ammonium sulfate precipitation.