Evidence against the occurrence of adenosine-3':5'-cyclic monophosphate in higher plants.

Previous reports on the incorporation of [(14)C]adenine into adenosine-3':5'-cyclic monophosphate (cyclic AMP) in oat (Avena sativa L.) and maize (Zea mays L.) coleoptile sections, chick-pea (Cicer arietinum L.) embryos and barley (Hordeum vulgare L.) aleurone layers were reexamined. Separation of labelled nucleotides on DEAE-Sephadex A 25 showed that a peak of (14)C activity, previously considered to be cyclic AMP, is not identical with this compound. Attempts to detect the cyclic nucleotide by means of a highly specific protein-kinase assay in various plant tissues (Nicotiana tabacum L., tissue culture; Catharanthus roseus Don., tissue culture; Lycopersicon esculentum Mill, seedlings; Nicotiana tabacum, pith parenchyma; Avena sativa, coleoptiles) failed even though up to 100 g of plant material was extracted and a number of control experiments were carried out to insure that cyclic AMP, if present in the extracts, could be measured.