TABLE 2.

InsP₃ and ATP sensitivity of mammalian InsP₃R isoforms

	InsP3 dependence		ATP dependence
InsP3R	kInsP3 (μM)	nHill	kATP (mM)	nHill	(Pm + P0)/P0
RT1	0.27 ± 0.07	1.6	0.13 ± 0.04	1.3	5.26
RT2	0.10 ± 0.01	2.2	N/A	N/A	N/A
RT3	0.40 ± 0.05	1.4	2.0 ± 0.1	4.1	7.14

N/A, not applicable.

Parameters k_InsP3 and n_Hill (InsP₃ dependence) were determined from the best fit to the data shown on Fig. 6 using Eq. 1, parameters k_ATP, n_Hill, P0, and Pm (ATP dependence) were determined from the best fit to the data shown on Fig. 8 using Eq. 2.