| 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) |
| 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) |
Km 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 (Km) 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.