Characterization of cyclic AMP phosphodiesterase isozymes in rat parotid gland

Cyclic AMP phosphodiesterase (PDE) isozymes were isolated and characterized from the soluble fraction of rat parotid gland. Four main peaks containing PDE activity were obtained by Q-Sepharose Fast Flow column chromatography. The four peaks were identified as PDEs I–IV by kinetic properties, molecular-weight analysis and their responses to effectors and inhibitors.