Table 1. R_max and EC₅₀ for 4-cmc and caffeine activation of calcium release from control and RyR1 carrying the indicated amino acid substitutions.

Results are means±S.E.M. (n=4–19 for 4-cmc measurements or 4–15 for caffeine measurements).

Cell type	Rmax 4-cmc	EC50 4-cmc (μM)	Rmax caffeine	EC50 caffeine (mM)
WT	0.36±0.03	136±33	0.33±0.03	1.08±0.33
Heterozygous R999H	0.37±0.14	191±27	0.34±0.02	1.40±0.27
Homozygous P3527S	0.23±0.04*	75±18	0.43±0.04	1.21±0.18
Heterozygous P3527S	0.34±0.04	157±21	0.40±0.03	1.56±0.47
Homozygous V4849I	0.36±0.05	184±23	0.36±0.03	1.39±0.31
Heterozygous V4849I	0.47±0.05	204±36	0.43±0.03	1.94±0.29

*, P<0.009 (Student's t test).