• 1 January 1979
    • journal article
    • research article
    • Vol. 5  (1) , 65-74
Abstract
A rapid, simple, and direct assay for rat brain 3'',5''-cyclic nucleotide phosphodiesterase activity is based on the effective separation of cyclic(c)AMP, cGMP or cCMP from their corresponding 5''-nucleotides and nucleosides by chromatography on a polyacrylamide-boronate gel. The affinity of the boronate residue for cis-diols results in the retention of 5''-nucleotides and nucleosides while 3'',5''-cyclic nucleotides are not retained. The coelution of all 5''-nucleotides and nucleosides allows for the accurate assessment of phosphodiesterase activity in preparations contaminated by other purine metabolizing enzymes such as 5''-nucleotidases and nucleotide and nucleoside deaminases. Phosphodiesterase activity assayed by this means yields linear reaction kinetics with respect to time and amount of enzyme protein. Low blank values obtained allow for detection of as little as 2-3% conversion of substrate to product.