2'- O- (2- Aminoethylcarbamoyl)adenosine- 3', 5'- cyclic monophosphate, immobilized on agarose gel (2'-AEC-cAMP-Agarose)[2'- O- (2- Aminoethylcarbamoyl)adenosine- 3', 5'- cyclic monophosphate, immobilized on agarose gel (2'-AEC-cAMP-Agarose)]