Premium
Separation and characterization of a novel isoenzyme of cyclic nucleotide phosphodiesterase from rat cerebrum
Author(s) -
Mukai Jun,
Asai Tomoko,
Naka Michiko,
Tanaka Toshio
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb14745.x
Subject(s) - phosphodiesterase , rolipram , cyclic nucleotide , isozyme , zaprinast , chemistry , cyclic nucleotide phosphodiesterase , nucleotide , biochemistry , enzyme , gene
Anion‐exchange chromatography on a Mono‐Q column of the supernatant fraction, after ultracentrifugation, from a homogenate of rat cerebrum, prepared under isotonic conditions in the presence of protease inhibitors, yielded a novel isoenzyme of cyclic nucleotide phosphodiesterase (PDE) with properties unlike those of known PDEs. The isoenzyme was insensitive to stimulation by Ca 2+ /calmodulin and cyclic GMP, and it hydrolyzed both cyclic AMP and cyclic GMP with K M values of 0.109 ± 0.008 μ m and 1.78 ± 0.04 μ m , respectively. The ratio of V max of hydrolysis of cyclic GMP to that of cyclic AMP was 1.90 ± 0.07. Nicardipine (PDE I inhibitor), SK&F 94120 (PDE III inhibitor), rolipram (PDE IV inhibitor) and zaprinast (PDE V inhibitor) had very weak inhibitory effects on the PDE activity of the isoenzyme. These results suggest that the isoenzyme is a novel and previously unreported species of PDE, which we tentatively designate PDE VIII.