Qualitative and quantitative mass spectrometric analysis of cyclic nucleotides and related enzymes

Abstract The application of fast atom bombardment mass spectrometry (MS) and collisionally induced dissociation with mass-analysed kinetic energy spectrum scanning to biochemical studies of cyclic nucleotides is reviewed. MS analysis of partially purified tissue extracts has enabled the demonstration of the natural occurrence in mammals and higher plants of five cyclic nucleotides in addition to the previously established adenosine 3′,5′-cyclic monophosphate; analysis of the products of a putative cytidylate cyclase enzyme-catalyzed reaction has demonstrated the biosynthesis of cytidine 3′,5′-cyclic monophosphate and four novel analogues as side products, thereby enabling the development of specific assays. Quantitative applications have included kinetic analysis of phosphodiesterase and cyclic nucleotide-responsive protein kinase activity, while further quantitative applications have included the structural elucidation of synthetic cyclic nucleotide derivatives used in pharmacological studies. The impact of MS upon cyclic nucleotide research and its future potential are discussed.