Table 1. Apparent affinities for nucleotide binding of nvTRPM2 N- and C-terminal sites.

Ligand	Km for nvNUDT9-H (µM)	EC50 (IC50) for nvTRPM2(µM)	EC50 (IC50) for hsTRPM2 (µM)
ADPR	4.1 ± 0.6	2.3 ± 0.2	1.4 ± 0.1 (Tóth et al., 2015)
dADPR	5.7 ± 0.6	2.7 ± 0.3	n.d.
Br-ADPR	3.4 ± 0.4	31.9 ± 2.8	n.d.
ε-ADPR	19.6 ± 2.6	(IC50) 269 ± 91	(IC50) 112 ± 24 (Iordanov et al., 2016)
ADPR-2′-phosphate	14.9 ± 4.0	0.42 ± 0.04	13 ± 1 (Tóth et al., 2015)

K_m values of the isolated nvNUDT9-H domain for hydrolysis of various ADPR analogues (left column), and EC₅₀ for nvTRPM2 channel activation (for ε-ADPR IC₅₀ for inhibition) by the same nucleotides in the presence of 125 µM cytosolic Ca²⁺ (center column). Data represent mean ± SEM obtained from least-squares fits of the Michaelis–Menten (K_m) or Hill (EC₅₀) equation to the respective dose–response curves. Right column lists published EC₅₀ (IC₅₀) values for activation (inhibition) of hsTRPM2 by ADPR analogues; to allow meaningful comparison, only reports that were obtained in inside-out patches, in the presence of saturating cytosolic Ca²⁺, are listed. n.d., not determined.