Differential susceptibility to biological detergents of the particulate cGMP-stimulated phosphodiesterase from rat heart: preservation of the allosteric properties of the solubilized enzyme.

The effects of various biological detergents on the particulate cGMP-stimulated cAMP phosphodiesterase activity from rat heart were investigated. When added to particulate fractions, anionic and non-ionic detergents diversely increased both cAMP and cGMP phosphodiesterase activities and slightly decreased the stimulatory effect of cGMP on cAMP hydrolysis whereas cationic detergents were rather inhibitory and drastically lowered the stimulatory effect of cGMP. Among the most efficient detergents, only sodium cholate was able to solubilize phosphodiesterase activity and preserve the stimulatory effect of cGMP on cAMP hydrolysis. Furthermore, the addition of glycerol significantly improved the conservation of the allosteric properties of the enzyme. Kinetic properties of the cholate-solubilized phosphodiesterase were quite identical to those of the membrane-bound enzyme.