Radioactive measurement of 2' ,3'-cyclic nucleotide 3'-phosphodiesterase activity in the central and peripheral nervous system and in extraneural tissue.

This paper describes a new, sensitive, and reproducible method for the determination of 2′,3′-cyclic-nucleotide 3′-phosphodiesterase (EC 3.1.4.37) activity in both central and peripheral nervous system tissue, as well as in extraneural tissue. Radioactive [8-³H]adenosine 2′,3′-cyclic monophosphate was used as the substrate. The [8-³H]2′-AMP product formed was isolated by thin-layer chromatography, or, alternatively, the reaction was coupled with an excess of Escherichia coli alkaline phosphatase, and the [8-³H]adenosine formed was isolated by column chromatography on AG 1-X2 resin. The values obtained by the two methods were compared with those obtained using a spectrophotometric method. Hydrolysis rates of 0.50 nmol/min could be reproducibly measured in 18-day fetal rat spinal cord.