Table 2.

Model parameters and the ranges of model parameters used

Variable	Cellular Concentration	Kinetic Parameter	Subcellular Location	Reference No.
AC	7.06 nM	cAMP production:	Subplasmalemmal region	(21)*
		basal, 1.0 nM/s
		forskolin, 20 nM/s
PDE	2.95 nM	Km = 2 μM;	Subplasmalemmal, cytosolic, or perinuclear region, as indicated	(17, 32)*
		Kcat = 100 cAMP/s
cAMP	Basal [cAMP] ∼ 50 nM	Effective diffusion coefficient = 300, 30, 3, 0.3 μm2/s, as indicated	Diffusible	(7, 15, 61, 66, 71)*
cAMP buffers	0 to 100 μM, as indicated	KD =100 or 460 nM, as indicated	Uniformly distributed within cytosol	(7, 27, 71)*

AC, adenylyl cyclase; PDE, phosphodiesterase.

^*Indicated parameter was manually fit to describe data in Fig. 2 or published work, as described in text.